Well Owner's Corner
Volunteers are Critical for GAMA Studies
The GAMA domestic well studies are designed to provide people who rely on water from private wells information about the quality of groundwater in their area. To carry out these studies, the USGS needs to take samples from domestic wells and relies on volunteers to make this happen.
The USGS team begins seeking volunteers at the beginning of each new study unit.
Want to learn more about your well, water quality, and how to protect it?
- SWRCB GAMA - Domestic Well Project Site
- SWRCB Domestic Well Owner Guide
- Water Systems Council: Water Well Help for Well Owners
- Valley Water: Private Well Owner Guide
This short list is a small fraction of the public information available; the USGS does not endorse any commercial products or services.
What to Expect as a Participating Well Owner
Volunteer well owners who participate in the study will receive a free chemical analysis of their well water.
Before releasing data or reports to the public, the State Water Resources Control Board (SWRCB) and USGS will provide results to individual well owners. Well owner information will be kept confidential.
If you choose to participate, your first step will be a conversation with a USGS scientist about the following details:
- Well construction: For example, well depth and depth to perforation. If you don't have a well completion report, we can look it up at the California Department of Water Resources archives.
- Sampling access: Is there a place to collect a raw groundwater sample from your well? Typically this is a spigot or threaded plug between the well and any treatment system. A USGS scientist can help determine this with you at your well.
- Pipe access: Can we measure the depth to water?
- Water flow: Can the pump be run continuously for about an hour?
If your well can be used in the study, we will make an appointment to visit your well with our field team and mobile laboratory to conduct sampling.
How and Why
Well Q & A
Frequently Asked Questions
The program is designed to give water managers in each region information about the quality of groundwater being used for drinking water supplies and to give volunteer well owners detailed analytical results about their wells. The data will be used to determine what factors are affecting water quality and how it changes over time. Water managers can then use this when planning for public supply treatment systems and when evaluating contaminant control measures.
You will learn more about your well, the depth to water in your well, and about the quality of the raw groundwater pumped from your well. If an elevated concentration of a contaminant is detected, then we will provide you with information on how to follow up.
There is no charge to participate in the study and results are provided for free. The program is funded by the State of California.
There are several things we need:
- Well Construction Details
For example, well depth and depth to perforation. If you don't have a well completion report, we can look it up at the California Department of Water Resources archives.
- Sampling Access
A place we could sample water from, typically a spigot or threaded plug between the well and any treatment system.
- Pipe Access
Can we measure the depth to water?
- Water Flow
Can the pump be run continuously for about one hour?
At the appointment time, a team of USGS scientists will arrive in our mobile laboratory, measure the water level in your well, let the pump run for about an hour, and then collect at most 60 water samples in prepared bottles. After the team leaves, the bottles are shipped to our National Water Quality Laboratory overnight.
The well must be available to pump continuously for about an hour.
Yes. Approximately 6 months after all of the wells are sampled for the study, we will send you a 'Well Owner Report' with the sampling results. We will include our contact information and a USGS scientist will be available to discuss the results and answer questions.
The sampling results will be used to provide information about groundwater quality in your area and statewide. This information is served through an online database at https://gamagroundwater.waterboards.ca.gov/gama/gamamap/public/, a USGS GAMA Groundwater-Quality Results web map, and through USGS publications available at https://ca.water.usgs.gov/projects/gama/includes/GAMA_publications.html
When a test result is over a Maximum Contaminant Level (MCL), the State recommends that well owners not drink the water, and talk to a water treatment professional. When results are above a health-based benchmark but below an MCL, or if no MCL has been established, the State recommends that well owners consider including these substances in any future water quality analyses they do on their own well. The health-based benchmarks represent the amount of a constituent in drinking water that if consumed by one million people over their lifetimes, would result in one person contracting cancer as a result. These benchmarks are conservative and designed for use by public water supply systems. More information is available here.