Sanitary Well Caps

Pennsylvania is one of only a few states that does not have mandatory statewide construction standards for private water wells. As a result, some important components of a properly constructed drinking water well may not be present on some wells. The most important features missing from some private water wells are a sealed, sanitary well cap and a grout seal. These components are required by most states because they help protect groundwater by sealing the well from potential surface contamination.

Standard well caps simply bolt onto the well casing and often allow for entry of insects, surface water, or small mammals into the well. A "sanitary" well cap (also called a "vermin-proof" well cap) looks similar to a standard well cap but has a rubber gasket to seal the cap to the casing and vertical bolts joining the two pieces of the well cap.

A study by Penn State documented the effect of installing a sanitary well cap on existing water wells. Sixteen private wells that contained coliform bacteria were disinfected with chlorine and fitted with a sanitary well cap. Of these wells, 44 percent did not contain coliform bacteria one month later and 19 percent did not contain bacteria after one year. The sanitary well caps were most successful in eliminating bacteria from wells that previously contained small numbers of coliform bacteria (< 3 colonies per 100 mL of water), compared to those that had more gross contamination. This Penn State study also looked at bacterial contamination in new wells that were constructed with a sanitary well cap and a grout seal. Only 29 percent of these new wells contained coliform bacteria, suggesting that proper well construction practices can reduce but not completely eliminate bacterial contamination. Wells drilled into aquifers that are contaminated by animal wastes, septic systems, or surface water can contain coliform bacteria regardless of well-construction practices.

Sanitary well caps are inexpensive and can easily be installed on an existing well by a qualified water well contractor.

To find a professional water well contractor in your area, consult the National Ground Water Association contractor look-up tool.