Testing and Treatment Options for your Private Well

Where can I get my well water tested?

Drinking water from private wells is at risk of contamination.  It is estimated that up to 30% of private wells may be contaminated  occasionally with E. coli (an indicator of recent pollution by human or animal waste).

As private wells are not regulated, it is up to the well owner to arrange to have their well tested.

To ensure that your drinking water is safe you should get it tested.  Test it preferably at least once a year for bacterial contamination and once every three years for chemical contamination, especially after heavy rain.  Remember, a test can only tell you about the quality of the water at the time of the test - the quality may change at different times.  If concerned arrange for a retest of  your water.

At a minimum, test for E. coli and coliform Bacteria.  The need for other tests depends on the location of your well and the appearance of your well water.  For example, if your well is in an agricultural area you may need to get it tested for nitrate or if it is slightly discoloured you may want to get it tested for iron and manganese.   You should consider testing the well if there is a vomiting or a diarrhoeal infection in the family.  When making arrangements with the laboratory you should describe any concerns you have about your well water and they will be able to advise on what specific tests should be carried out.

A number of private laboratories are available to carry out the analysis.  Your local authority Environment Section or Environmental Health Officer will be able to advise on a suitable laboratory.  Alternatively, you can get the name of a suitable private laboratory from the Goldenpages. 

The Irish National Accreditation Board (INAB) publish a list of laboratories that it has accredited to the ISO 17025 standard in recognition that they comply with testing in accordance with international and European standards. INAB’s Directory of Accredited Bodies for laboratory testing can be found at this link http://www.inab.ie/Directory-of-Accredited-Bodies/Laboratory-Accreditation/Testing/
The directory lists the “Company Name”, “Activity” (note: Microbiological and Chemical testing activities applies to drinking water) and the “Download Schedule” of tests the laboratory is accredited for.
Click on the pdf in the “Download Schedule” column to determine if that laboratory is accredited for the microbiological or chemical parameters you want to test for in your water supply. Also, check that the Annex to the laboratory’s Accreditation Certificate states it facilitates a public testing service.

To determine if a laboratory is accredited for chemical testing of drinking (potable) water, look for the code “766.01 Waters for potable and domestic purposes” in the Schedule of Accreditation under the column “INAB Classification Number (P9) Materials / Products tested”. The column next to this “Type of test/properties measured” will list the chemical parameters that this laboratory is accredited to test for (e.g. nitrite, nitrate, ammonia, pH, iron, manganese, lead, colour, etc.)
Similarly, to determine if a laboratory is accredited for microbiological testing of drinking (potable) water look for the code “870.11 Bacteriological condition of potable water” in the Schedule of Accreditation under the column “INAB Classification Number (P9) Materials / Products tested”. The column next to this “Type of test/properties measured” will list the microbiological parameters that that laboratory is accredited to test for (e.g. faecal coliforms, E. coli, Enterococci, etc.)

The United Kingdom also have an Accreditation Service, called UKAS. UKAS is similar to INAB in that they are both accreditation bodies which are signatory to the European Co-operation for Accreditation (EA) multi-lateral agreement for testing.
Both UKAS and INAB have signed up to the EA Multilateral Agreement (EA MLA) which is a signed agreement between the EA Full Members. This means the signatories recognise and accept the equivalence of the accreditation systems operated by the members. There are some UKAS accredited testing laboratories  in Ireland and they can be found at this link; https://www.ukas.com/list-all-organisations/?org_type=2&parent=Testing%20Laboratories&org_cat . You can browse the laboratories  that test drinking water by clicking the “Testing Laboratories” link, then “Environmental Samples” and  select “Water, Drinking / potable”.
It is important to follow the instructions of the laboratory when taking and handling the water sample as this may affect the reliability of the results.

Do I need to treat my well water?

If test results indicate that your well is contaminated, you should take action to protect it.  Also, if it is contaminated with infectious organisms (bugs, bacteria, germs), the water should be boiled until the well water is safe to drink.

You may need to install some type of treatment if your well is located too close to a polluting activity or if the water is still contaminated after you have taken steps to protect the well.  There is no “one size fits all” solution.  The type of treatment depends on the quality of your well water.  Remember that any treatment system must be properly maintained and operated to do its job properly, otherwise it could pose a health risk.

Below is a list of the main treatment types used in private wells:

  • Chlorination – chlorine is the most commonly used disinfectant in Ireland however; it may not be suitable for on-going disinfection in private wells due to the low doses required. It is suitable for disinfecting a well on an intermittent rather than on-going basis.   It protects against pathogens but not against Cryptosporidium.
  • UV treatment – Ultraviolet light is a very effective disinfectant at killing pathogens and Cryptosporidium, if used correctly. UV will only work properly if the water is clear and contains low levels of iron and manganese (which can cause fouling of the lamp).
  • Jug filters/cartridge filters – these types of filters can remove certain substances, which can lead to improved taste and acceptability of water but while most will generally not remove infectious organisms, certain specialised filters will.
  • Water softener – these are used to reduce the hardness of your water to prevent damage to your appliances.  These are ion exchange units where, in most cases salt is added to remove the hardness.  Water softened in this way  can have high levels of sodium (Na) in it.  It is not suitable for drinking, cooking or preparing babies bottles but it can be used for other purposes such as showering or washing.
  • Reverse osmosis (RO) – RO is a membrane based treatment where water is moved across a membrane (using pressure) to remove ions and other impurities.   It may be necessary to re-mineralise water produced by RO.

The type of treatment suitable for your well depends on the results of appropriate testing.  You can get a list of suppliers of water treatment systems in the Goldenpages.  You should advise any potential suppliers of water treatment systems of these results so that they can advise you on the most suitable treatment for the problem.

Any treatment system installed must be maintained and operated in accordance with the manufacturers specifications or it may not do the job it is intended to do and could pose a risk to your health.

Alternatively you should check with Irish Water or your local group water scheme to see if you can connect to a nearby public or group water scheme.