CORVALLIS, Ore. - Recent rain and floods have homeowners worried about their wells and septic systems. To ensure safe drinking water taken from private wells, the Oregon State University Extension Service recommends following guidelines from the U.S. Environmental Protection Agency.

The guidelines are online at:

"The main requirement is one minute of boiling at a full rolling boil," said Gail Andrews, OSU Extension's well water specialist. "Start timing when the water reaches a full rolling boil."

When boiling water is not possible, household bleach can be used to disinfect well water, according to Andrews. Procedures for using chlorine bleach to treat drinking water are outlined on the EPA site and are sometimes printed on the bottle of chlorine bleach.

If you think your well might be contaminated, you should treat it as if it is contaminated until you know differently, said Andrews. Get a Coliform bacteria test from a certified laboratory, she added, suggesting homeowners call several labs to compare prices if there are multiple options. For a list of labs, see:

If there are no water-testing labs in your area, Andrews recommends contacting local real estate offices. Water tests are required for sales of property with wells, so realtors will have information that may help.

If you find that your well water is contaminated by flooding streams or rising groundwater, it won't do any good to shock-chlorinate the well until the water level has gone down, Andrews said. You may have to use alternative water sources until the water recedes and then shock-chlorinate and re-test the water. For information on shock chlorination, see:

Heavy rains and floods may also affect septic systems. If septic drain-lines are flooded or if they pass through saturated soil, plumbing fixtures will drain slowly or back up. In this case, use as little water as possible and wait for the water to go down.

There is no quick fix for flooded septic lines, according to Andrews. You can't unclog the drains. Contact your county septic permitting official for additional advice. For a list of county water resources, see:

For further information on wells and septic tanks, see

For printed copies of this information, contact your local county office of OSU Extension.


Gail Andrews, 541-737-6294

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