Coliform Bacteria Water Testing Labs in Oregon (48 state-certified labs)

How many labs test for coliform bacteria in Oregon

48 labs on Oregon's official drinking-water lab list are certified to test for coliform bacteria. All 48 are named for coliform bacteria on the list. 37 of them are marked as taking samples from the public. They are listed first. 18 are located outside Oregon.

The list is published by the Oregon Health Authority (OHA) - Oregon State Public Health Laboratory, Oregon Environmental Laboratory Accreditation Program (ORELAP). List version on file: search as fetched 2026-11-15 (live database, no list date). Fetched 2026-11-15 (UTC).

Oregon labs certified for coliform bacteria

Marked as taking public samples (37)

Other labs on the list (11)

How the Oregon list marks public samples (whole list). Yes for labs ORELAP marks as accepting public samples (OHA: "these laboratories can accept samples from anyone"); No for drinking-water labs without that mark (mostly utility and federal labs).

Before you send a sample, call the lab to confirm it is currently certified for the exact test and method, that it accepts samples from homeowners, and how to collect and ship them. Status can change between list updates.

Why test for coliform bacteria in Oregon

About a third of the 397 domestic wells tested for bacteria in a national USGS study had total coliform. Read our coliform bacteria explainer.

EPA advises private-well owners to test every year for total coliform bacteria, nitrates, total dissolved solids and pH. [1]

Oregon guidance that mentions coliform bacteria:

• OHA says Oregon requires well testing only when a property with a well is sold, but it recommends testing for coliform and E. coli bacteria every year, nitrate every year, and arsenic every 3 to 5 years. You may need to test more often if the well has a history of contamination, the septic system recently malfunctioned, household members have a stomach illness, infants drink the water, or any equipment has broken. OHA lists typical costs of $20 to $40 for the bacteria and nitrate tests and $25 to $45 for arsenic. [2]
• Oregon State University's Well Water Program advises testing for coliform bacteria at least once a year, when taste or color changes, after work on the well, if the well cap is not secure, or if surface water stands around the well. It suggests testing for nitrate if a pregnant woman or newborn will drink the water, and once a year if you live near fertilized fields, septic systems or livestock, or have had nitrate before. [3]
• In the LUBGWMA program the first test covers nitrate, arsenic, lead, total coliform and E. coli. Depending on the nitrate result, OHA and the county health departments offer free retesting; households at 10 mg/L or more qualify for free drinking water delivery, and those between 10 and 24.99 mg/L are also offered a free reverse osmosis system. OHA says free testing is not available to households outside the LUBGWMA. [4]
• Under Oregon's Domestic Well Testing Act (ORS 448.271), the seller of real estate with a domestic well must have the well water tested for arsenic, nitrate and total coliform bacteria by an accredited lab. Within 90 days of receiving the results, the seller or their representative must send the results to the buyer, and a Real Estate Transaction (RET) form plus the results to OHA. Properties with spring wells or irrigation-only wells are exempt. [5]

About 631,538 people in Oregon used private wells in 2015, by the USGS estimate of people on domestic self-supplied water. [6] Federal limits are written for public water systems, not private wells, so testing is up to the owner.

For tests that depend on your home (farms nearby, old plumbing, a new baby), use the which-tests checklist. When results arrive, check your numbers against EPA's limits. State guidance, county data and every lab: Oregon.

Other tests in Oregon