NYSDOH website
Many people in the United States receive their water from private ground water wells. EPA regulations that protect public drinking water systems do not apply to privately owned wells. As a result, owners of private wells are responsible for ensuring that their water is safe from contaminants (CDC).
The NYS Department of Health recommends that you test your well water at least once a year for bacteria, and every 3-5 years for other contaminants. The most basic test for bacterial contamination of a water supply is the test for E. coli and coliform bacteria. To learn more about recommended water analyses for other contaminants in residential drinking water wells, see Individual Water Supply Wells: Fact sheet #3, NYSDOH(PDF, 147KB), (Recommended Residential Water Quality Testing).
Search for a Certified Water Testing Lab in the Tompkins County area.
When rain falls, much of it is absorbed into the ground. Water that is not used by plants moves downward through pores and spaces in the rock until it reaches a dense layer of rock. The water trapped below the ground in the pores and spaces above the dense rock barrier is called ground water, and this is the water we get when we drill wells. Another common term for a source of ground water is “aquifer” or “ground water aquifer.”
Since surface waters such as lakes, reservoirs, and rivers are more susceptible to contamination that groundwater is. Surface water may more easily contain bacteria, parasites, viruses and possibly other contaminants. Shallow groundwater wells are also at significant risk of contamination.
These water sources may be considered only as a last resort with proper protective measures and, in most cases, will require approval by County or State health department officials through issuance of a specific waiver pursuant to Part 75 of the State Health Department's Administrative Rules and Regulations or via a county sanitary code waiver provision (NYSDOH).