Is my well water safe to drink right now?

No. Treat a positive result as not-safe-to-drink until your local health department tells you otherwise. Use bottled water or another verified safe source in the meantime.

Do I need to disinfect the well myself?

Contact your local health department first — they can tell you the specific disinfection protocol they want followed in your area, rather than guessing from general guidance.

How long after disinfection can I test again?

CDC guidance on well disinfection calls for waiting at least 7 to 10 days before retesting, so any chlorine used in the process has fully flushed out and won’t produce a false clean result.

What if the retest is still positive?

CDC guidance is to repeat the disinfection process and test again. If it stays positive after that, contact your local health department for assistance rather than repeating it a third time on your own.

My well water tested positive for bacteria — now what?

right away, and . That's the CDC's own two-step answer — an immediate precaution, then a call to the people who know your area's specific protocol.

Checked against CDC guidance, 2026-09-15. General information, not a substitute for your local health department's specific instructions.

Step one — stop drinking it, don't panic-diagnose it

. You don't need to figure out which specific bacteria or how it got there before taking this step — treat any positive coliform result the same way until you've talked to someone qualified.

Step two — call your local health department

. This matters because disinfection protocols and follow-up requirements vary by state and county — your local department is the authority on what applies to you, not a national guidance page.

How the disinfection process generally works

The exact protocol your health department gives you governs — this section is general background, not a do-it-yourself instruction set. CDC's published well-disinfection procedure (written for emergency/flood situations, but describing the same shock-chlorination method many health departments use for a routine positive test) calls for a strong chlorine solution run through the well and plumbing, left in place for a set period, then flushed out.

On retesting, CDC guidance is specific: , testing . Testing too soon risks a false clean result from leftover chlorine, not an accurate read on the well itself.

If it's still positive after disinfection

. Two positive results in a row is the point to stop self-managing it and get direct help, not the point to try a third round alone.

Sources & last verified

. Checked 2026-09-15.
. Checked 2026-09-15. Written for emergency situations; cited here only for the general disinfection/retest method, not as a substitute for your local health department's protocol.

Found something out of date? Email corrections@homecleared.com.

Common questions

Is my well water safe to drink right now?: No. Treat a positive result as not-safe-to-drink until your local health department tells you otherwise. Use bottled water or another verified safe source in the meantime.
Do I need to disinfect the well myself?: Contact your local health department first — they can tell you the specific disinfection protocol they want followed in your area, rather than guessing from general guidance.
How long after disinfection can I test again?: CDC guidance on well disinfection calls for waiting at least 7 to 10 days before retesting, so any chlorine used in the process has fully flushed out and won’t produce a false clean result.
What if the retest is still positive?: CDC guidance is to repeat the disinfection process and test again. If it stays positive after that, contact your local health department for assistance rather than repeating it a third time on your own.