How to test and treat my residential well water?


Thank you for your question! Be sure to check out OSU's Well Water Program webpage for additional information.

Treating your well water

Ultraviolet (UV) is the treatment that would kill the E. coli bacteria without additional chemical treatment. I always recommend UV installation at the end of the system, right before the water enters the home.

UV disinfection is very effective. If you are still wanting to shock the system, chlorinate the well and flush through the holding tank. One-time use of chlorine bleach will not damage the light.

If the UV is installed before the holding tank, you will want to shock just the water in the tank and flush at least 500 gallons of water out of the tank and through the rest of the system.

For more information about wells, check out the following resources:

Getting your well water tested

The following resources from the Oregon Health Authority (OHA) include a list of private labs that do well water testing in Oregon and other general information about testing:

Please note that there is a fee for testing.

The following tool from Colorado State University (CSU) can help you interpret your test results and get a general understanding of them. Unfortunately, this tool does not have Oregon as an option for which state you are from, so I use Utah and use this tool as a guide rather than a perfectly accurate interpretation.

Was this page helpful?

Related Content from OSU Extension

Have a question? Ask Extension!

Ask Extension is a way for you to get answers from the Oregon State University Extension Service. We have experts in family and health, community development, food and agriculture, coastal issues, forestry, programs for young people, and gardening.