My Aquifer > For Private Well Owners > How can I test the quality of my private drinking water supply?


You should test private water supplies annually for nitrate and coliform bacteria to detect contamination problems early. Test them more frequently and for more potential contaminants, such as radon or pesticides, if you suspect a problem.

If you use a private laboratory to conduct the testing, nitrate and bacteria samples will typically cost between $10 and $20 to complete. Testing for other contaminants will be more expensive. For example, testing for pesticides or organic chemicals may cost from several hundred to several thousand dollars.

Many laboratories are available to test water quality. EPA does not test individual homes, and cannot recommend specific labs to test your drinking water, but states certify water testing labs. You may call your State Certification Officer to get a list of certified water testing labs in your state. Some local health departments also test private water for a fee or sometimes even free.

Most laboratories mail back the sample results within days or several weeks. If a contaminant is detected, the results will include the concentration of the contaminant and an indication of whether this concentration exceeds a drinking water quality standard. If a standard is exceeded in your sample, retest the water supply immediately and contact your public health department for assistance. Some problems can be handled quickly. For example, high bacteria concentrations can sometimes be controlled by disinfecting a well. Filters or other on-site treatment processes may also remove some contaminants. Other problems may require a new source of water, or a new, deeper well. If serious problems persist, you may need to rely on bottled water until a new water source can be obtained.