Drinking water

This method is for the disinfection of a well water supply, water storage tank, water carrying pipe work and hot and cold-water cylinders. Approximately 1,100 litres of water will be used.

Caution: if you have a filter or any other type of water treatment on any part of your system, consult your supplier before following this procedure. Heavily chlorinated water may affect the filter or the chlorine may be absorbed by the filter rendering the procedure ineffective.

1. To 25 litres of water add 5 litres of a 1% w/v solution of Sodium Hypochlorite. While we do not endorse any individual products, any one of the following products may be used diluted in 25 litres of water.

(a) 2.5 litres of Milton fluid (or 50 tablets) or similar products with 2% w/v Sodium Hypochlorite.

or

(b) 0.5 litres of Sterichlor or similar products with 10/11% Sodium Hypochlorite.

Disinfection products sold for use on the farm will be acceptable for use in disinfecting wells. However, it is important to seek advice about their use and it is advisable to always use the products in about 25 litres of water.

2. Pour half of the solution into the well.

3. Turn on the drinking water tap in the kitchen and let the water run until there is a distinct smell of chlorine from the water. Then turn off the tap.

4. Turn on all other taps and let the water run until there is a distinct smell of chlorine from the water. Then turn off the taps.

5. Pour the other half of the solution into the well. Turn off the well pump and ensure that the well is covered properly. Allow to stand overnight or for at least 8 hours.

6. After at least 8 hours reconnect the pump. Turn on all taps and let the water run until the smell of chlorine is gone. Turn off all taps.

7. Arrange for the water to be tested.

N.B. This method is only suitable as a once off shock disinfecting procedure and cannot replace a proper treatment system if your water supply needs continuous disinfection.

Yes, if your water becomes discoloured at certain times (e.g. after heavy rainfall or when slurry is spread on land nearby) then it is possible that surface water is getting into your well which is likely to be contaminated. You should get your well tested when it becomes discoloured. If you suspect that your well is contaminated with infectious organisms (bacteria / bugs / germs), you should boil your water before using it for drinking, washing teeth, preparing food and making ice until you know that the water supply is safe.

The first step is to talk to your neighbour about the suspected cause of contamination. It may be that your neighbour is unaware of the location of your well or the consequences of their actions. If this fails you should make your complaint in writing to the relevant local authority or use the EPA “See It, Say It” app to report the incident.

You should check your well to see if there are any obvious signs of contamination such as recent landspreading or cattle too close to your well. Protecting the catchment area of your well is one of the best ways to protect the quality of your water. You should also check to see is there any ingress of water into the borehole.

If your well is contaminated with E. coli or Coliform Bacteria you should boil the drinking water from the well until you are sure it is safe to drink and cook with.

You should sterilise your well (see How do I disinfect my well question) and see if this resolves the contamination (after retesting). If this is not successful in restoring the quality of your water you may need to consider improving the protection of your well and/or installing an appropriate treatment system. Once-off disinfection cannot replace a treatment system if your supply is always or often contaminated.

If your well is contaminated with a chemical parameter you should contact your local authority for advice in the first instance.

You may also consider connecting to a public or group water scheme.

No, it does not mean it is safe to drink. Some contaminants such as E. coli may not cause your water to be discoloured. It is advisable to get your well tested once per year (ideally during poor weather conditions).

If your water is occasionally or frequently discoloured it may be an indication that your well is contaminated from time to time. It is advisable to get your well tested the next time it becomes discoloured and consider boiling that water until you are sure it is safe.

Just because the usual householders are not getting sick, doesn't mean that the well is safe. Visitors may be more susceptible to low level contamination because they may not have developed immunity to the infectious organisms that may be in your well.