Contamination risk from wells

Greater danger of illness from private water wells

Digging wells to avoid water charges may not be as attractive an option as it seems to some people.

Nearly one of three private wells in Ireland are contaminated by E coli, says the Environmental Protection Agency, which has issued timely householder information on private wells.

“What is not generally known is that there is a greater risk of illness associated with private well supplies,” householders are advised.

“You may have been using your well for years and have had no health problems as you may have built up immunity to the contamination. However, friends, family and children may become ill as a result of consuming your well water.”

What are the main risks to the safety and quality of water in my well?

The main risk to your well is contamination from human or animal waste.

Many areas in Ireland have high groundwater vulnerability, which makes contaminatin of well water more likely.

If your well is vulnerable to contamination and is not properly constructed, it is possible that human or animal waste from septic tanks, landspreading or runoff from the surrounding land may enter your well.

Contaminated water can make you or anyone who consumes the water ill.

If you are concerned about your well water, contact your local authority or your HSE Environmental Health Officer for advice. If you suspect that your water may be contaminated it may be advisable to boil your water until you have had your well water tested.

I am using a deep well, how can it be contaminated?

While a shallow well is likely to be vulnerable to contamination, a deep well is not necessarily protected against contamination.

Contamination can travel over the top of the well casing (e.g. if the wellhead is below ground), down the sides of the casing (if not properly sealed) or can travel through the soil into the well. Contamination of groundwater through abandoned boreholes nearby is another potential risk.

Unless the well is properly constructed, sealed and cased then it may be vulnerable to contamination from contaminated water from the surface.

My water becomes discoloured sometimes, is this something I should be concerned about?

Yes, if your water becomes discoloured at certain times (e.g. after heavy rainfall or when slurry is landspread 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.

My water smells sometimes, what is causing this and should I be concerned?

There are several types of possible smells from your well, all with different causes.

The most common types of odour are rotten eggs (from sulphur reducing bacteria), mustiness, sewage/slurry, hydrocarbons (i.e. petrol, diesel or kerosene) and chlorine (if the well has been disinfected).

Some of these odours may indicate a risk to your health and you should arrange for your well to be tested.

You should boil the water if you suspect contamination with infectious organisms (bacteria / bugs/germs).

You should advice the laboratory of the odour you detect in the water when getting it tested.

Some contaminants such as E. coli may not cause your water to smell. Even if there is no odour it is advisable to get your well tested at least once per year (ideally during poor weather conditions to rule out breakthrough contamination when the supply would be more vulnerable).

Where can I get my water tested?

Your local authority Environment Section or the HSE Environmental Health Officer will be able to advise on a laboratory.

Alternatively, you can get the name of a suitable private laboratory from the Goldenpages.

What should I get it tested for?

It is most important to get your water tested for E. coli and Coliform Bacteria.

The need for other tests depends on the location of your well and the appearance of your 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. 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.

It is recommended that you test your well water at least once a year for microbiological contamination and every three years for chemical contamination.


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