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GAMA - Domestic Well Testing

How Do I Test My Well?

A water testing laboratory can test your well water. The laboratory will supply the sampling bottles and can help you sample your own well. Search the Division of Drinking Water’s Geographic Information System (GIS) Map to find ELAP-accredited laboratories in your area:

Prices for sampling and testing will vary; ask the lab for a written estimate before sampling. Water quality self-testing kits are available from hardware and home warehouse stores and can be useful in evaluating whether a contaminant is present. However, sampling your well and having an accredited laboratory test your well water is more accurate and reliable.

If you still have questions regarding how to sample your well, please email Dori Bellan at:

What Should I Test For?

The location of your well can have a direct influence on what chemicals to test for in your water. These can include, but are not limited to, bacteria, metals, and nitrate.

Since 2002, GAMA has tested over 1,000 private domestic wells in the state. The following list of chemicals and test methods highlights chemicals we have found and their associated laboratory testing method. This list is provided as assistance for your decision making process only.

How Much Will Sampling Cost?

Basic sampling can cost from $100 to $400. Hiring an outside business to sample your well and interpret the results will likely cost more. Ask an accredited laboratory from the DDW list above for a written cost estimate of exact prices before sampling.

How Do I Know If There’s A Problem With My Well’s Water Quality?

To assist you in understanding your test results, we have provided a link to reference information for standards that apply to public drinking water supplies.

Comparing your well water test results to public drinking water standards is helpful. However the quality of the water from your well is not regulated by the State of California. These public drinking water standards were established by DDW for the protection of public health from public drinking water supplies.

It is suggested that you re-test your well for any constituent found in concentrations above a primary MCL. Annual testing of domestic wells used for drinking water is recommended by the US EPA.