Frequently Asked Questions (FAQ’s)

Wastewater treatment systems for single houses

The following provide answers to the frequently asked questions about wastewater treatment systems for single houses in general and questions on the EPA’s guidance document – Code of Practice: Wastewater Treatment and Disposal Systems Serving Single Houses (p.e. <10).

If your query is not answered below and if it relates to a site-specific question then you should contact your local authority in the first instance. Local authorities can contact the EPA for advice and assistance if they have specific technical questions about the wastewater treatment code of practice. If your question is about planning permission then you should contact your local authority, as this is an area that is not dealt with by the EPA.

The EPA wish to acknowledge the input and work from Ms. Martina Smith and the Clean Water Team at Monaghan County Council in preparing these questions.


General Wastewater

What is included in the term domestic wastewater?
Domestic wastewater includes grey water and sewage from domestic dwellings.  Grey water is defined as wastewater that comes from sinks and washing machines, i.e. the wastewater that contains some bleach and detergents.  The grey water from your household is treated in the same way as sewage whereby it is collected in a septic tank and undergoes treatment either in a percolation area or in a secondary treatment unit prior to being discharged via a polishing filter to ground. Rainwater is not classified as grey water and therefore should not be discharged into your wastewater treatment unit.

What happens to wastewater from my home?
When houses are not served by a public sewerage system, the wastewater from a house should be treated by a septic tank and percolation area or advanced wastewater treatment system. With new houses the type of system used is determined by testing ground/soil conditions at planning stage.
How should a septic tank wastewater treatment system work?

A modern septic tank system includes a double chamber tank and percolation area. Wastewater is partially digested by bacteria in the septic tank and the effluent then passes through a percolation area where effluent is further treated.

Typical layout of a septic tank and percolation area

Typical layout of a septic tank and percolation area

Typical layout of a septic tank and percolation area

Should ‘grey water’ from dishwashers, sinks and washing machines be directed to my wastewater treatment system?
YES - grey water should in all circumstances be directed to the wastewater treatment system. Grey water is also a pollutant and if directed to the rain water system may cause contamination of waters. Take care with house extensions or alterations – don’t connect any wastewater pipes to the rain water disposal system.
Should water from roofs and yards be connected to my wastewater treatment system?
NO - Roof and yard waters should not be connected to your wastewater treatment system. Clean water should be collected and discharged separately to a local watercourse or soakaway.
How do I dispose of the rainwater and clean surface runoff from my site?
Uncontaminated water should be disposed of by means of a soak pit/soakaway.  The soakaway should be designed in accordance with the guidance provided in BS8301 and in BRE Soakaway Design (1991). It should not be located within 5m of any dwelling and as far away as possible from the percolation area (at least a minimum of 5m separation distances should be used).
How do I know if my wastewater treatment system is not working properly?

Some signs that your wastewater treatment system may not be working include the following:

  • Smell of sewage from the general area of the tank and percolation area.
  • Slow draining toilets, sinks or drains or backing up of sewage at the inlet.
  • Overflow of wastewater from the tank or ponding of sewage on the percolation area.
  • Discolouration of nearby watercourses (greyish slime growths).

Discharge from a defective septic tank

Discharge from a defective septic tank
My house is over 20 years old – how do I know if it is working effectively?
Septic tanks prior to the 1990’s may not be built to current standards and performance should be checked. You should check tank structure, provide access points for maintenance and de-sludging, replace soak-pits and pipes to drains (if present) with a properly designed percolation area or other approved polishing system, exclude roof and yard water from the system.
I have noticed ponding in my garden close to my wastewater treatment system, what should I do?

First of all you should arrange to have your system de-sludged. If it is an advanced wastewater treatment system you should contact the supplier/installer of your system and have your system serviced.

Ponding of sewage effluent

Ponding of Sewage Effluent 
Could my wastewater treatment system pollute my well?

Yes it is possible. If you suspect that your wastewater treatment system is affecting your well you should have it checked.  If you are concerned you should contact your local authority’s Environmental Section or local Environmental Health Officer for advice. 

If you suspect contamination of your well you need to have a full assessment of your wastewater treatment system carried out by a suitably qualified person.

Contamination from soak pit entering the household well

Contamination from soak pit entering the household well 

New Sites or Houses

When buying a house what do I need to do?

Before buying a house you should have the septic tank or wastewater treatment system inspected by a suitability qualified person. You should ask for installation and maintenance records for the system. You should check that the treatment system will adequately serve the anticipated number of occupants of the house.

If the house is served by a DWWTS, the seller of the house should provide you with a copy of the certificate of registration for the domestic waste water treatment system as provided for in Section 70 D of the Water Services (Amendment) Act 2012.

http://www.irishstatuebook.ie/2012/en/act/pub/2002/print.html

The new homeowner is obliged to inform the local authority of the change of ownership and such that the register can be updated.

I want to extend – can I build over my septic tank system and percolation area?

Under no circumstances should you build over a septic tank or percolation area. Access to the tank is needed for regular maintenance and the percolation area should not be compacted.

Even with a hard standing area located above a percolation area traffic may damage percolation pipes and result in ponding or escape of untreated effluent.

Can I place a car park or driveway over the percolation area or polishing filter?
Roads, driveways or paved areas or any underground services must not be located within the disposal area.  This is due to the need to have easy access to the site for maintenance and also to prevent problems with the system due to the potential for damage to the pipework and compaction of the filter materials.
Are all sites suitable for septic tanks and other individual wastewater treatment systems?
 NO– not all sites are suitable. The following are possible reasons for site unsuitability:
  • A high water table.
  • A slow percolation rate of the soil which would result in ponding on the surface because effluent cannot get away
  • A fast percolation rate of the soil, which would result in effluent moving through the soil too quickly without effective treatment.
  • Site restriction issues i.e., not enough space to achieve the minimum separation distances between the treatment system and domestic wells, watercourses, other houses etc.

The site suitability assessment process will determine the suitability of a site but the ultimate decision will rest with the local authority or planning authority


Maintenance

Why do I need to de-sludge my domestic wastewater treatment system?

If the level of sludge builds up in the tank it may make its way out of the tank and block the distribution box and the percolation area or polishing filter. And if the percolation area or polishing filter becomes blocked it is very difficult to clean and may require replacement – an expensive option!

The minister has published new regulations (Performance Standards S.I. No 223 of 2012) governing the operation and maintenance for domestic wastewater treatment systems (DWWTSs).  These require owners of DWWTS to operate and maintain their systems and this includes de-sludging.

How do I care for my domesitc wastewater treatment system?
You should visually check your system at least every six months and note any ponding of effluent, bad smells or discoloration of nearby drains. If you have an advanced treatment system check the electrical components (pump, blower etc) are operational. 

Don’t be tempted to turn off the power to save electricity - If there is no air going to the system it becomes an undersized septic tank and treatment is ineffective. You should also check the distribution box i.e. the manhole between the wastewater treatment system and the percolation area to ensure even distribution of effluent and ensure there are no blockages.

How often do I have to de-sludge the septic tank?

It is recommended to de-sludge a septic tank at least once a year but this varies with the system’s capacity and use.  You must de-sludge the septic tank if scum is present in the second chamber or if the sludge comes up to about 400mm from the bottom of the tank. A minimum of 75mm of sludge should remain in the tank to assist in the re-seeding of the new sludge.  Regular maintenance is required to ensure that the septic tank operates effectively and that solids do not enter the percolation area and clog the distribution pipe work.

What effects will oils and greases have on my wastewater treatment system?
Oils and grease from cooking that escape down the drain can damage your system. Food waste and cooking oils can be recycled (see information below) and avoid the use of food macerators or “in-sink disposal units” Excess amount of food, grease or oils will cause blockages, smells, overload your treatment system and damage you percolation area.
What are grease traps and what do they do?

Grease traps capture the oil and grease from the flow of wastewater by slowing down the flow of hot greasy water through the trap and allowing it to cool.  As it cools, the grease and oil separate out of the water and float to the top of the trap.  The cooler water then flows to the septic tank where it is treated.  Grease traps are usually not included in the design of a domestic wastewater system but are mandatory in systems treating water from restaurants, hotels and any other businesses that supply food.  

Due to the absence of these systems in single dwellings it is highly important that people do not allow any fats, grease or oils to enter their septic tank systems.  The inlet pipes can become clogged up by the fats and grease and therefore can reduce the treatment rate of the septic tank system.  To insure that this doesn’t happen to your system, all fats, grease and oils must not be disposed down the sink or drains.

What effects could using a macerator or in-sink disposal unit have on my wastewater treatment system?
Adding macerated food waste to your wastewater increases the organic strength of the wastewater. This in turn could result in inadequate treatment, blocked pipes and smells arising from the tank or percolation area.
Will bleach or disinfectants harm the domestic wastewater treatment system?
Normal amounts of household bleach, disinfectants and detergents will not harm the domestic wastewater treatment system.  However, excessive amounts of bleach will temporarily reduce the treatment capacity, as the microorganisms needed to treat the biological waste will be killed off.  In saying this, the system should return to full performance capacity within a short period of time. It is important to be aware of potential effects that excessive use of these chemicals will have on your wastewater treatment system.
Do I really need to renew my maintenance agreements?
Yes.  All on-site wastewater treatment systems require ongoing maintenance to ensure that the system is providing adequate treatment of the wastewater.  An on-going maintenance agreement should be made and renewed with an appropriately qualified person to ensure that your wastewater treatment system is working effectively at all times.
How often do I need to empty my domestic waste water treatment system (DWWTS)?

The frequency of de-sludging is dependent on the size of the tank and the number of persons living in the house.

Best practice for the management of DWWTS indicates that de-sludging should be undertaken when the level of sludge on the bottom of the tank is greater than approximately 400 mm. A minimum of 75mm of sludge should remain in the tank to assist in the re-seeding of the new sludge. Regular maintenance is required to ensure that the septic tank operates effectively and that solids do not enter the percolation area and clog the distribution pipe work.

What volume of Septage (includes effluent, sludge and scum) will be arising from domestic waste water treatment systems?

In Ireland, there are approximately 440,000 houses with domestic waste water treatment systems and on the basis of US figures the annual septage volume can be estimated at 0.372 x 109 litres /year or 372,000 m3/year.

Who can take the DWWTS sludges?

It is recommended that a waste contractor that has an appropriate waste collection permit be employed to de-sludge a septic tank or DWWTS.  A list of approved permit holders is available from the Environment Section of your Local Authority.

What records do I need to keep?

Householders having their septic tanks de-sludged should ensure that they retain a receipt from the permitted waste undertaker who de-sludges the tank. 

The receipt should include the following information: 

  • Name, address and Permit Number of the waste collector.
  • Date of desludging.
  • Quantity removed and destination to where the sludge is to be taken for treatment and disposal/recovery.
Can sludges from DWWTS be landspread?

Individual landowners can dispose of sludges from their own DWWT system by land spreading, strictly in accordance with the requirements of the Waste Management (Use of Sewage Sludge in Agriculture) Regulation, S.I. No. 148/1998, as amended.


Permitted waste collectors can also dispose of sludge’s by  landspreading  where their Waste Collection Permit allows them to do so strictly in accordance with the requirements of the Waste Management  (Use of Sewage Sludge in Agriculture) Regulation, S.I. No. 148/1998, as amended.

Where should the sludge go?

The Permitted Waste collector must ensure that sludges are treated and disposed/recovered in accordance with legislative requirements. 


Septic Tank Flooding

What should I do if my septic tank is flooded?

If possible, the system should not be used until flooding subsides below the level of the tank, but this is more to prevent water backing up into a property than any other reason.

In short, many systems will be robust, they will be recovered and will be usable after a flood.

Where electrical components are used or damage is suspected - then a professional assessment (and repair) is necessary.

There is no significant environmental concern above and beyond that posed by the wider flooding event.

Septic Tanks - What to do after flooding?
  1. Due to the potential for toxic gases in all septic systems, any servicing, cleaning, repairs, internal damage assessments and emptying/pumping must be carried out by trained and experienced specialists.
  2. After the flooding subsides, replace any dislodged manhole covers and check the system for any external signs of damage such as settlement, ponding of waste water, overflowing, blocked drains or not accepting water from the house.
  3. If you suspect damage, or if your system relies on electrical components such as pumps, have the entire system assessed by a professional service engineer.
  4. Ensure that any nearby private wells are checked and disinfected prior to use by following the EPA advice (available on www.epa.ie) for private well owners on what to do after flooding. (See https://www.epa.ie/newsandevents/news/)

As always, do not enter flood waters as manholes may have been dislodged and the flood water will be contaminated and may pose a risk to health.


Complaints

I am concerned that my neighbours’ treatment system is contaminating my well. What can be done about this?

In the first instance, you are advised to contact the local authority.  In relation to the concern that the wastewater treatment system is potentially contaminating the well, advice should be sought from the environment section and the local Environmental Health Officer (EHO).

In addition to the above, Section 70 of the Water Services Act 2007  (Water Services Act 2007) sets out the general duties on an owner of a domestic wastewater treatment system.  It provides that the local authority or 'any other person affected by the failure...' may complain to the District Court if there is a failure by the owner of the domestic waste water treatment system (DWWTS) to comply with the general duties set out.  See provisions below in subsection 6 and 7.

“(6) A water services authority or any person affected by a failure, or alleged failure of a third party to comply with a duty of care provided for under this section may complain to the District Court, and the Court may order the third party to take the measures necessary to effect a cessation of the activity which is the subject of the complaint, or to take specified measures to effect compliance with their obligations under this section.

(7) Before a complaint is made to the District Court under subsection (6), the water services authority or the person concerned, as the case may be, shall serve a notice in the prescribed form of the intention to make such a complaint, within such time as may be specified in the notice, on the said third party.”

The Water Services Act was amended in 2012 Water Services (Amendment) Act 2012) and provides additional requirements on the owner of domestic waste water treatment systems (DWWTSs) in terms of performance of their systems.  New regulations (Performance Standards S.I. 223 of 2012) have been published in relation to the operation and maintenance of DWWTS.   

 

There is a problem with my neighbours’ treatment system, which is impacting on my property. What can be done to get this resolved?

In the first instance, you should contact the environment section of the local authority for advice.

However, Section 70 of the Water Services Act 2007 (Water Services Act 2007)  sets out the general duties on an owner of a domestic wastewater treatment system.  It provides that the local authority or ‘any other person affected by the failure…’ may complain to the District Court if there is a failure by the owner of the domestic waste water treatment system (DWWTS) to comply with the general duties set out.  See provisions below in subsection 6 and 7.

“(6) A water services authority or any person affected by a failure, or alleged failure of a third party to comply with a duty of care provided for under this section may complain to the District Court, and the Court may order the third party to take the measures necessary to effect a cessation of the activity which is the subject of the complaint, or to take specified measures to effect compliance with their obligations under this section.

(7) Before a complaint is made to the District Court under subsection (6), the water services authority or the person concerned, as the case may be, shall serve a notice in the prescribed form of the intention to make such a complaint, within such time as may be specified in the notice, on the said third party.”

The Water Services Act was amended in 2012 (Water Services (Amendment) Act 2012)  and provides additional requirements on the owner of domestic waste water treatment systems (DWWTSs) in terms of the performance of their systems.  New regulations (Performance Standards S.I. 223 of 2012) have been published in relation to the operation and maintenance of DWWTS.   

 

What role does the EPA have in relation to checking that a treatment system is suitable and installed properly?
The EPA does not have a role in assessing compliance with planning conditions.  It does however, provide advice to local authorities in relation to wastewater treatment through the publication of guidance manuals and advice where requested. It is the responsibility of the local authority through its planning section to enforce the conditions of planning and the environment section enforces water pollution legislation.

Legal Position

What are my rights in relation to site assessment or wastewater treatment services?
Contact the National Consumer Agency, Telephone Number: 01 402 5500.
What laws are in place in relation to my wastewater treatment system?
Section 70 of the Water Services Act, 2007 places a Duty of Care on owners of premises and states the following

“The owner of a premises shall ensure that all drains, manholes, gullytraps and storage and treatment systems for wastewater, including related accessories, not in charge of a water services provider, which serve that premises are kept so as not to:-

(a)   cause, or be likely to cause, a risk to human health or the environment, including to waters, the atmosphere, land, soil, plants or animals, or

(b)   create a nuisance through odours.”

For new builds site characterisation must be carried out in accordance with the EPA Code of Practice for Wastewater Treatment and Disposal Systems Serving Single Houses (p.e≤10), 2009. The EPA Code of Practice can be downloaded at the following location http://www.epa.ie/downloads/advice/water/wastewater/

Section 3 of the Local Government, (Water Pollution) Act, 1977 as amended by the Local Government, (Water Pollution) Amendment, Act, 1990 prohibits the entry of polluting matters to waters.

If using a contractor to de-sludge you wastewater treatment system you must ensure that the contractor holds an appropriate Waste Collection Permit for European waste code 20 03 04. You may be breaking the law if you use an unlicensed contractor to de-sludge your system. A list of licensed contractors operating in is available from your local authority.

What are the legal standards that I must comply with in relation to the installation of a wastewater system for a single house?
Septic tanks installed on or after 1 June 1992 must comply with Part H of the National Building Regulations.  The relevant Technical Guidance Document (TGD) - H (Drainage and Waste Water Disposal) calls up the following standards in the revised document published in 2010:
  • The design and installation of wastewater treatment systems for single houses should comply with the relevant parts of the Environmental Protection Agency’s (EPA) Code of Practice 2009 Wastewater Treatment and Disposal Systems Serving Single Houses; and
  • Guidance on the design and installation of wastewater treatment systems capable of serving larger buildings or more than one house is contained in I.S. EN 12566 Parts 1- 4, BS 6297: 2007 Code of Practice for the design and installation of drainage fields for use in wastewater treatment and the EPA’s Wastewater treatment manual – Treatment systems for small communities, business, leisure centres and hotels: 1999.

EPA Guidance and Training Information

What guidance is available from the EPA on installing a treatment system for a single house?
The Code of Practice Wastewater Treatment and Disposal Systems serving Single Houses (p.e. £10) published by the EPA in 2009 replaces previous guidance issued in 2000 and provides guidance on installation of on-site wastewater treatment systems.  It is designed to help planning authorities, builders and others to deal with this issue.
Where can I purchase a copy of the Code of Practice Wastewater Treatment and Disposal Systems serving Single Houses (p.e. 10) ?

There are a variety of ways to obtain a copy of the Code of Practice Wastewater Treatment and Disposal Systems serving Single Houses (p.e. £10)  

The Wastewater Treatment Manual for Single houses can be downloaded from www.epa.ie

It is also possible to purchase the Wastewater Treatment Manual by writing to:

Publications Office
Environmental Protection Agency,
PO Box 3000,
Johnstown Castle Estate,
Wexford

Or calling Publications Office at 053 9160642

Payments may be made by cheque, postal order or bank draft made out the Environmental Protection Agency or by credit card for web and telephone sales.

How can I apply for the ‘Site Suitability Assessments for On-Site Wastewater Management’ training course?

This course is no longer being run by FAS.  However, you are advised to contact the Water Services Training Group for information on when this course will be run.

 

Water Services Training Group,

Monastery Road, Roscrea, Co. Tipperary
Phone: (0505)24688 | Fax: (0505) 23427 | E-mail: wsntg@eircom.net


Site Characterisation

What is involved in carrying out a Site Characterisation?
Site characterisation involves the characterisation of the ground conditions of the site and then the selection of an appropriate wastewater treatment system. The objective of site characterisation is
  • to determine if the site can adequately treat the wastewater;
  • to check that  the treated wastewater can get away; and
  • to check that the minimum site separation distance can be achieved.

Detail of how to carry out site characterisation for a wastewater treatment system for single houses can be obtained in Section 6 and Annex C of the Code of Practice Wastewater Treatment and Disposal Systems serving Single Houses (p.e. £10) (2009).

Where can I find a qualified person to carry out a Site Suitability Assessment as part of a planning application for a single house?
Local authorities are responsible for determining who is qualified to carry out site suitability assessments within their functional area.  In some cases local authorities have a list of designated persons who may carry out the assessment; these can be found on their websites or by contacting the Planning or Environment Section of the local authority.  In cases where a list is not drawn up then contact the Planning or Environment Sections directly for information on their minimum requirements.

A list of persons having successfully completed the FAS training course may be available from FAS at 01 6070500.  Otherwise prior to employing a site suitability assessor ask to see a copy of their FAS certificate as proof of completion of the course.

What is a percolation test?

A percolation test is a method of assessing the ability of the subsoil to allow water to percolate to the water table (i.e. how water can pass through the soil). In the test a small hole is excavated and the time taken for the water to drop in minutes is recorded.  It is recommended that a suitably qualified person carry out percolation tests.  Contact your local authority to obtain a list of qualified persons.  For more information on these tests, see Annex C of the CoP.

Percolation test

Percolation test
What is the minimum recommended distance between two percolation test holes?
Test holes should be located at either side of the proposed percolation area (but not within it), to ensure that the percolation characteristics are assessed across the percolation area.
What is the difference between “T” and “P” tests?
Both of these are percolation tests that assess the ability of the subsoil to allow water to percolate to the water table. The main difference is that they are carried out at different levels. A “T” test is used to test the suitability of the subsoil at depths greater than 400mm below the ground level. A “P” test is carried out at ground level where there are limiting factors such as high water table or shallow rock.
Which percolation test method should I use?
Flow Diagram for Carrying out Percolation Tests 
Flow diagram for carrying out Percolation test

 Ϯ or as far as possible for the more slowly draining subsoils

* if the water fully percolates within 10 minutes then proceed to Step 3

What is the modified test method? When is it to be used?
The modified percolation test is a new test that will reduce the amount of time required to be spent on-site to obtain a percolation test result in areas with low permeability soils/subsoils.  The modified test should be used in the case the initial drop T100 >210 minutes or where the site assessor expects that the result will be above 75.
I have got very different percolation test values from my site – what do I do?
Three percolation test holes are required for all sites.  Where there is a high degree of variability in the subsoil characteristics then additional tests could be carried out.  The results of these tests should be examined in light of the other three test results.  A detailed examination of the subsoil types within the trial hole and the individual test holes should be undertaken to determine the dominant site conditions.  The dominant subsoil type in the test holes and trial hole should be taken, as representative of the site conditions and therefore the percolation test results that equate to that should be used.
What can I do if the T test fails?

If a T test fails; a P test should be carried out only where the T test result is less than 90. If the percolation test result is greater than 90 then discharge to ground is not recommended as ponding will occur. 

The P-test will establish if it is possible to install a constructed percolation area or a polishing filter. It determines whether the upper layers of the subsoil are permeable enough to allow percolation of the treated wastewater into the ground. 

If the P test passes it may be possible to install a secondary treatment unit with a polishing filter – see Sections 8, 9 and 10 of the CoP for more details.

If both the P and T test fail, it is only permitted to discharge the effluent to surface waters.  A water pollution licence must be obtained from your local authority.  See Section 6 and Annex C of the CoP for more information on P and T tests.

How can I tell if I have a high water table?
A high water table can be determined by constructing a trial hole and leaving it open for 48 hours during the site assessment.  The water level should be measured from ground level.
What can I do if I have a high water table?
A depth of 1.2m of free draining subsoil (1£ T £ 50) to the bedrock must exist at all times for a septic tank system.  If this is not the case, the use of a septic tank system is not recommended but a suitable secondary treatment system may be installed if the subsoil has a percolation rate (T/P test result) between 1- 75 and there is a minimum of 900mm unsaturated subsoil (i.e. water table is at least 900mm below the ground surface) so that a polishing filter may be constructed.
Is it permissible to have more than one house sharing a septic tank and well?
This is a matter for the planning authority.
What information can a local authority request in relation to the suitability of a site?

A planning authority is currently entitled to request any information on site suitability for an on-site wastewater disposal system from the applicant that it considers necessary to make a decision on an application for planning permission.  Under Article 22 (2)(c) of the Planning and Development Regulations 2006, where it is proposed to dispose of wastewater other than to a public sewer, the applicant must submit information on the type of on-site wastewater treatment system proposed and evidence as to the suitability of the site for the system proposed as part of the planning application.

How can I go about selecting a wastewater treatment system?
Details of the different on-site wastewater treatment systems, both septic tank systems and package treatment systems, can be found in the Agency’s Code of Practice Wastewater Treatment and Disposal Systems serving Single Houses (p.e. £10) (2009).  This code outlines each of the requirements for wastewater treatment systems.

Selecting and Designing a System

How do you determine what type of wastewater treatment system is required for a single house?

Firstly, a suitably qualified person must carry out a site assessment in accordance with the guidance set out in the Code of Practice Wastewater Treatment and Disposal Systems serving Single Houses (p.e. £10) (2009).  This is then followed by the selection of a suitable wastewater treatment system, which is dependent on the site conditions determined during the site assessment.

The choices of on-site wastewater treatment and disposal systems are;

  • Septic tank systems – septic tank and a properly constructed percolation area
  • Secondary Treatment System: Constructed On-site – septic tank, filter system (including constructed wetlands) followed by a polishing filter for discharge to ground.
  • Secondary Treatment: Packaged Wastewater Systems – package system followed by a polishing filter for discharge to ground.
  • Tertiary Treatment Systems – polishing filters, constructed wetlands or package tertiary systems.

It may be required to discharge effluent to surface waters if the percolation tests fail, in which case a discharge licence from your local authority is required.

What is an acceptable housing density?
The CoP sets out minimum separation distances between wastewater treatment systems and vulnerable features including houses, wells and watercourses. However, the planning authority may increase these distances where it is deemed appropriate. One of the limiting factors for the siting of a wastewater treatment system is the existing level of nitrates in the groundwater.  If the nitrate levels in the groundwater in a particular area are elevated due to the high density of wastewater treatment systems in that area, then the Local Authority may seek additional information (including dilution calculations) to assess any potential impact on the groundwater quality from any proposed development. Section 6.4 and Annex D.2 of the CoP provides more details.
Why and how is a dilution calculation performed?

A dilution calculation is carried out to estimate the potential impact on the groundwater quality of allowing a wastewater treatment system to be installed. The only parameter that Local Authorities would need to vary is recharge, which could be reduced in the drier counties. Recharge rates may be obtained from Met Eireann. Details on carrying out dilution calculations may be found in Annex D.2 of the CoP.

Who certifies the design of Wastewater Treatment Systems?
A treatment system should meet the requirements of the EN 12566 series of standards developed by the European Committee for Standardisation TC 165.  Innovative products and technologies, not specifically covered by national or European harmonised standards should be certified, be fit for the purpose for which they are intended, the conditions in which they are used and meet the performance requirements of the CoP. 

The Irish Agrément Board is part of the National Standards Authority of Ireland (NSAI) and is the national certifying body. Its function is to assess, test, and where appropriate, issue Agrément Certificates in respect of materials, products, systems and technicques used in the construction industry, particularly those used of an innovative nature, in order to facilitate their ready acceptance and their safe and effective use. Agrément Certificates provide the Board's opinion of the fitness for specified purposes of materials, products, systems and techniques, taking into account the context in which they are to be used.

Do I need a licence to discharge directly from a wastewater treatment system to surface water or groundwater?

A water pollution discharge licence is required from the local authority

  • If the treated effluent is discharged to surface waters

Or

  • If the quantity of treated wastewater is greater than 5m3/day and is being discharged to groundwater. 
Contact your Local Authority’s Environment Section for more information or to apply for a water pollution licence. Application forms may be downloaded from the local authority’s website. Most local authorities do not allow discharges from a single house to surface waters.

Protection of Wells and Water Courses

How far away from a wastewater treatment system is it safe to locate a well so as to prevent contamination?
The minimum recommended distance between a water well and a wastewater treatment system (including percolation area or polishing filter) septic tank is set out in the Groundwater Protection Responses[1] (amended 2009 – Annex B), where zoning for groundwater protection schemes outlines the aquifer classification in the general area and the vulnerability of the groundwater. The minimum distance of wells from wastewater treatment systems and percolation areas/polishing filters are set out in Table 1.

[1] Groundwater Protection Schemes 1999 EPA/DEHLG/GSI can be purchased from the EPA Publications Office or from the EPA website.

Is the density of rural housing an issue for water quality?

Yes in some cases – a clustering of wastewater treatment systems in areas with poor soil percolation properties may pose a risk to local surface waters while a clustering of wastewater treatment systems in areas with very shallow soil and high percolation rates may pose a risk to local ground waters. The use of soakpits significantly increases the risk factor and households using soakpits should consider upgrading their systems. It is likely that the use of soakpits will be targeted in new legislation and in measures adopted to protect surface and ground waters.

Recommended Minimum Distance between a Receptor and a Percolation Area or Polishing Filter

Recommended Minimum Distance between a Receptor and a Percolation Area or Polishing Filter


What are the minimum separation distances to rivers, beaches, lakes, etc?

The minimum recommended distances for the above are set out in Table below.

Minimum Separation Distances in metres

Minimum Separation Distances in metres  

What is a percolation area?
A percolation area typically consists of a system of sub-surface perforated pipes which allow the liquid waste to be absorbed and filtered by the soil.
Is it possible to disinfect a contaminated well?

To disinfect a well you must:

1.     Obtain 9 litres (2 gallons) of 3% strength or 4.5 litres (1 gallon) of 5% strength e.g. Parazone) bleach. 

2.     Make up to 22.5 litres (5 gallons) by adding water and mix thoroughly. 

3.     If sampling during a pumping test, on the day before the test starts pour half of the solution into the well.

4.     Start the pump and let it run briefly until water with a distinct smell of chlorine pours from the outlet pipe.

5.     Turn off the pump immediately. Add the remainder of the solution and leave overnight.

6.     Pump to waste until the smell of chlorine disappears before taking a sample for analysis. 

If sampling from a well that is connected to a house, pour half of the solution into the well, start the pump and open all taps until water from each tap has a distinct smell of chlorine. Stop the pump and add the rest of the solution. Allow this to stand for 12-24 hours and then pump to waste until the smell of chlorine disappears.       

In addition you should try to determine what is causing the contamination. What activities are taking place within 50m radius of the well?  Is there adequate protection around the top of the well?

For more information on disinfecting wells, see the GSI website. http://www.gsi.ie/everyone/faqs/water/faqwater.htm#gw8


Septic Tanks, Percolation Areas and other Filter Systems

Is a reserve percolation area required?
The Agency’s CoP does not require a reserve percolation area but requires a rigorous site assessment, correct installation and proper maintenance of the wastewater treatment system. In addition, minimum separation distances must always be achieved.
What is an individual or an advanced wastewater treatment system?
Individual or advanced wastewater treatment systems consist of mechanical aeration or filtration units that enhance the treatment of domestic wastewater. A polishing filter is installed after these systems to allow further treatment of the wastewater. These systems may be suitable in some areas where a septic tank system is not acceptable.  The EPA 2009, Code of Practice: Wastewater Treatment and Disposal Systems Serving Single Houses (p.e.≤10) provides general guidance on the location, design, installation and maintenance of both secondary treatment filter systems and packaged wastewater systems. 
What is a polishing filter?
Polishing filters consist of either soil or sand and are employed to reduce micro-organisms from wastewater. They are used to treat wastewater from intermittent filters, constructed wetlands and packaged treatment systems and to allow for the discharge of treated wastewater to ground. See the Section 10 of the CoP for more information.

What is the difference between a soil polishing filter and a sand polishing filter?
Soil polishing filters comprise in-situ or improved or imported soil, whereas sand polishing filters are comprised of layers of sand. See the Section 8 Secondary Treatment: Systems Constructed On-site for more information. 
I want to use a constructed wetland as my wastewater treatment system. What should I do?

A site suitability assessment is required to be completed prior to selecting any system.  If the site is suitable for a constructed wetland then the following should be noted.

Any discharge from a constructed wetland to surface water requires a water pollution discharge licence in accordance with the Water Pollution Acts 1977-1990. Specific information can be obtained from the local authorities.

If discharging from the constructed wetland to ground, a polishing filter will be required.  If the discharge is greater than 5m3/day, then a water pollution discharge licence is required as well as additional prior investigations. 

It should also be noted that constructed wetlands should be inspected weekly to ensure that there is no evidence of varying flow distribution or blockage, that the sidewalls are maintained and that the reeds have not been damaged. See the Wastewater Treatment Manual for Single Houses or contact the Environment Section of your local authority for more information.

Who installs Wastewater Treatment Systems? What are the requirements?
A suitably qualified installer should install on-site wastewater treatment systems; this includes septic tank systems, secondary treatment: systems constructed on-site and secondary treatment: packaged systems.  The secondary treatment systems are required to be followed by polishing filters.  Usually, the manufacturer will recommend a person who is suitable to install the system or may install it themselves.  This person is then responsible for the testing of the system after installation, to ensure that it is working effectively. In all cases the installation of the on-site wastewater treatment system should be certified.  Contact the local authority for more details as to their specific requirements.
Can I have trench widths greater than 500mm in my percolation area?
 The recommended trench width is 500mm.  The percolation trench lengths given in Section 7 of the Agency’s CoP is dependant on this trench width of 500mm.

How do I construct a percolation area on a sloping site?
Mound systems can be constructed on a sloping site, if the slope of the site does not exceed 12%. They must be constructed carefully along the contour to ensure that minimum installation thickness is maintained and to assist the even distribution of wastewater.
What are the key installation requirements for SOIL filters?
See Table 8.1 on page 28 of CoP
What are the key installation requirements for SAND filters?
See Table 8.2 on page 30 of CoP.
Who supplies sand filters in Ireland?
Unfortunately we do not have a list of suppliers for the materials used in the construction of sand filters but refer to the specifications set out below. 

Legislation

Why has legislation on domestic wastewater treatment systems been changed?

The European Court of Justice has ruled that countries must comply with certain standards and procedures, such as inspections, to ensure that public health and the environment are protected.

Poorly constructed or operated on-site wastewater treatment systems (including septic tanks) for single houses can result in sewage contaminating drinking water supplies or ponding on land, presenting a risk to human health as well as the environment.

Who has to register under the domestic wastewater treatment systems legislation?

All homeowners that have domestic wastewater treatment systems (DWWTS) are required to register their systems with the local authority where the DWWTS are located.

 

However, owners of properties connected to larger on-site systems where the discharge is in excess of 5 cubic metres per day do not need to register (i.e sports clubs, pubs, hotels, guesthouses and other businesses).  Instead such systems may require a licence from the relevant local authority under Section 4 of the Water Pollution Act 1997. 

 

To register please go to www.protectourwater.ie

 

If my house shares a domestic waste water treatment system with one or more houses, who is required to register?

In the situation where more than one house shares a domestic waste water treatment system, each individual household must register.

How do I register and with whom?

Owners of domestic waste water treatment systems are required to register their systems with their water services authority.  They can register online, by post or at your local authority office.

Online - www.protectourwater.ie - by credit card/debit card.

By Post:Registration forms are available online; from City/County Councils; Libraries; Citizen Information Centres or Lo Call 1890 800 800.

Payment can be made by cheque, postal order or bank draft and made payable to “Protect Our Water". Send your form with payment to: Protect Our Water, P.O Box 12204, Dublin 7.

Local Authority Offices:Payment by credit or debit card or by cheque, postal order, bank draft or cash can be made in your City or County Council office (no administration fee will be charged by the Council for this).

Do I have to pay anything to register?

A once off registration fee of €50.00 is payable to cover the costs of administration by the WSA and of the risk based inspection.

Having registered and paid my fee, is my septic tank going to be inspected?

The legislation requires the EPA to develop a ‘National Inspection Plan’.   A risk based approach is beiing used to select sites for inspection.  What that means is that the areas at most risk of contamination of groundwater, surface water or human health are more likely to be inspected first.  The risk maps are available to view at http://gis.epa.ie/myenvironment#/search.

 

What will happen if I don’t register or pay?
A person who fails to produce a valid certificate of registration commits an offence and can be fined.
Is there a deadline for registration?

All existing DWWTS should have registered by the 1st February 2013, if you have not registered already you may still do so, see www.protectourwater.ie for more information.

All new developments where a DWWTS is constructed or installed shall ensure that the system is registered with the WSA within 90 days of connection of the premises to the DWWTS (S.I. 180 of 2013).

If my septic tank is to be inspected who will carry out the inspection?

An appropriately qualified and EPA registered inspector. A list of authorised inspectors will be made available in due course. The local authority will inform you in advance if you have been selected for inspection. Inspections are due to commence in July 2013.

What will the inspector be looking for?
The inspector will carry out a visual inspection of the domestic wastewater treatment system. They will be checking to see that the system is being operated and maintained properly and is not posing a risk to human health or the environment.
Do I have to be there when the inspection is being carried out?

No access to the house itself will be required. The local authority will advise you of the inspection in advance.

Will I know if my septic tank has been inspected?
The inspector will be required to inform you of the findings of their inspection.
What happens if the inspection shows that there is a problem with my septic tank?
You are required to maintain and operate your septic tank or domestic wastewater treatment system in a manner that does not cause a risk to human health or the environment. If problems are found during the inspection the local authority may require you to carry out specific improvements to your system. 
If improvement works are required, who will pay?

The Minister for the Environment, Community and Local Government has announced a grant scheme for those who fail an inspection.  More details may be obtained for the DECLG's website - grant information.

How do I become an inspector?

The Minister has made regulations regarding the appointment of inspectors (S.I. No. 384 of 2012).  The regulations state tha the EPA shall appoint a person to inspect DWWTS if:

  • the applicant has attained a qualification at level 8 in the National Framework of Qualifications or equivalent, such qualification to be in construction, engineering or science disciplines, or, where such qualification is not attained, the Agency, having considered the qualifications and professional experience of the person by reference to the functions to be performed by an inspector for the purposes of the Act is satisfied that the person is suitably competent for appointment as an inspector, and
  • it is satisfied that the applicant has successfully completed a training course provided by the Local Authority Services National Training Group in relation to the inspection of domestic waste water treatment systems,
  • the applicant is indemnified by the relevant water services authority in accordance with Section 29 of the Act.
What are the performance standards that septic tanks and domestic wastewater treatment systems have to meet?

The Minister has published new regulations (Performance Standards S.I. No 223 of 2012) governing the operation and maintenance for domestic wastewater treatment systems.   

What role does the EPA Code of Practice 2009 have to play in relation to existing houses?

The standards in the Code of Practice: Wastewater Treatment and Disposal Systems Serving Single Houses 2009 (CoP) apply to all new developments. They do not strictly apply to existing houses, however, where problems arise improvements may be necessary in line with best practice as outlined in the code. The local authority may allow variations to the CoP when it is satisfied that the proposed improvements will reduce the impact on human health and the environment.

The Code of Practice is available to download at http://www.epa.ie/downloads/advice/water/wastewater/code%20of%20practice%20for%20single%20houses/#d.en.27967.

Do I have to register my domestic waste water treatment system (DWWTS) if the discharge is subject to a discharge licence under the Water Pollution Acts?

All homeowners that have domestic wastewater treatment systems (DWWTS) are required to register their systems with the local authority where the DWWTS are located.

However, owners of properties connected to larger on-site systems where the discharge is in excess of 5 cubic metres per day do not need to register (i.e sports clubs, pubs, hotels, guesthouses and other businesses).  Instead such systems require a licence from the relevant local authority under Section 4 of the Water Pollution Act 1997.