Simple steps to protect your well
Nearly 50,000 may be contaminated by E coli, says the Environmental Protection Agency (EPA), which has issued new advice on private wells.
According to the Health Service Executive, people treated for VTEC (Veritoxigenic E Coli) are four times more likely to have consumed untreated water from private wells. Ireland has the highest rate of VTEC in Europe. VTEC is a toxin producing form of E coli, and is a lot more serious than an ordinary tummy bug. However, by taking simple steps to protect your well this disease is preventable.
No, however, 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 indicate 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 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.
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 Golden Pages.
My well is contaminated, where can I get information on the substance that it is contaminated with?
The laboratory that carried out the analysis should be able to provide some information on the contaminant detected. Also, the National Federation of Group Water Schemes has also published a plain English guide “External linkWhat’s in Your Water?” on the parameters most commonly tested for.
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 fior 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 next 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.
This method is for the disinfection of a well water supply, water storage tank, water carying 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.
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 Hypoxhlorite.
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.
Pour half of the solution into the well.
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.
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.
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.
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.
Arrange for the water to be tested.
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.
You can get information on the current drinking water quality standards from the most recent EPA reports on The Provision and Quality of Drinking Water in Ireland.
Information on groundwater vulnerability is available from the website of the External linkGeological Survey of Ireland.
Guidelines on Water Well Construction are available from the Institute of Geologists in Ireland and from EPA Drinking Water Advice Note No.14 Borehole Construction and Wellhead Protection.
The HSE has published information on the risk of illness from well water, E Coli (VTEC) and cryptosporidiosis. The HSE cautions against switching from public water supplies to existing private wells.
Water charges do not apply to private well owners if they are not also connected to a public water supply.
