Well Water Testing Near Portland, Oregon

Why it's on you

Public water systems in Oregon are regulated and tested. Private household wells are not, so routine testing is up to the owner. It matters most when the well is your main source of drinking water.

What to test and how often

• Coliform bacteria: every year.
• Nitrate: every year.
• Arsenic: at least once, to learn whether it is present.

Other contaminants can be tested less often or when there is a reason to suspect them. Use an accredited laboratory, and follow its sampling instructions closely, since the way a sample is taken affects the result.

If arsenic comes back

1. If the first test is above 8 parts per billion, retest.
2. If the retest is 10 parts per billion or higher, install a treatment system.
3. With treatment in place, test each year at the tap and every three years at the wellhead.

If bacteria come back

Retest first. If bacteria are confirmed, the usual next steps are disinfecting the well and finding how they got in. A cracked cap, a damaged casing or water pooling at the wellhead are common places to look.

A well company can inspect the cap, the casing and the seal, and disinfect the well. The state's Domestic Well Safety Program, 971-673-0440, can help you read the results.

Simple checks between tests

• Make sure the well cap is tight, in good repair and, if vented, screened.
• Keep the casing at least a foot above the ground and undamaged.
• Don't store fuel, pesticides or other chemicals near the well or in the pump house, and don't keep animals there.