Information for Homeowners with Private Wells

Approximately 23 million people in the United States obtain water from their own private water supplies. Most of these supplies are drawn from groundwater through wells. It is recommended that owners of private wells inspect, chlorinate and test their well water annually.

How do I test my well water? What should I test for?

You should test private water supplies annually for nitrate and coliform bacteria to detect contamination problems early. Test the water more frequently and for more potential contamination, such as pesticides, if you suspect a problem. Bacteria testing typically costs between $15-$25 to complete. Testing for other contaiminants will be more expensive. For example, testing for pesticides or organic chemicals may cost several hundred to several thousand dollars.

Many laboratories are available to test water quality. Laboratories are certified by the Department of Environmental Protection. You should ensure that the lab you are doing business with is certified to perform the lab test you are requesting. Listings can be found in the yellow pages under Laboratories.

If a standard is exceeded in your sample, retest the water supply immediately and contact the Board of Health. Some problems can be handled quickly. For example, disinfecting the well can sometimes control high bacteria concentrations. Filters or other on-site treatment processes may also remove some contaminantes. Other problems may require new source water or a new, deeper well.

How do I inspect my private well?

• Periodically inspect exposed parts of the well for problems such as
• cracked, corroded, or damaged well casing
• Broken or missing well cap
• Settling and cracking of surface seals

How do I chlorinate my private well?

You can disinfect the well by using chlorine bleach or hypochlorite granules according to the manufacturer's directions. One procedure for disinfecting using bleach is as follows:

1. pour a solution of three gallons of water and one pint of 3% to 6% commercial bleach directly into the well,
2. open all faucets until there is an odor of chlorine apparent and then close all faucets for ten hours to allow the bleach to kill bacteria present in the pipes, storage tank or well,
3. open all faucets and let the water run until the odor and taste of bleach have disappeared,
4. have a sample of water, taken 24 hours after disinfecting, tested at a certified laboratory to determine that the water is suitable for use.

Note: This procedure results in a high level of chorine so the water should not be used for drinking, cooking, or watering livestock until the chlorine odor and taste is no longer apparent. Use of bottled water or boiling water is suggested if citizens are unsure of the purity of their water supply.

What can I do to protect my well?

• Slope the area around the well to drain surface run-off away from the well
• Install a well cap or sanitary seal to prevent unauthorized use or entry into the well.
• Keep accurate records of any well maintenance, such as disinfection or sediment removal
• Hire a licensed well driller for any new construction, modifications, or repairs
• Do not cut off the well casing below the land surface.
• Avoid mixing or using pesticides, fertilizers, herbicides, degreasers, fuels, or other pollutants near your well.
• Pump septic systems as often as recommended.