Why is private well water my responsibility?
Public water systems are regulated and tested. Private wells usually are not, and testing rules vary by state and county. That means the owner decides when to test, what to test for and what to do about results.
Water can look, smell and taste fine and still have germs or chemicals in it. Testing is the only way to know.
Even a well that tested clean last year can change. Land use nearby, heavy rain and aging well parts all affect water quality over time, so past results are a guide and not a guarantee.
What should I test for and how often?
Ask your state or county health department or extension office which tests make sense in your area. Common categories include bacteria, nitrate, and local issues such as naturally occurring minerals or contaminants linked to nearby land use. Many states publish testing guidance for private wells.
Test at least once a year for the basics, after floods, after repairs or if the water changes in taste, color or smell, or if someone becomes ill. Use a certified laboratory and follow the lab's instructions for collecting samples.
Keep a folder with test dates, results, well construction records and contractor receipts. If you buy or sell property, these records are useful, and your lender or local health department may ask for them.
- Use a state-certified laboratory
- Test after floods, repairs or any change in water
- Keep the results in a file
- Ask the health department which tests apply locally
How do I protect my wellhead?
Keep the area around the well clear of chemicals, fuel, manure, fertilizer and pesticide storage. Make sure the ground slopes away from the well so surface water drains away. Keep the well cap tight and in good condition, and keep animals away from it.
Ask your local health department or a licensed well contractor about recommended distances between wells and sources of contamination such as septic systems, livestock yards and fuel tanks, since rules differ by location.
What can contaminate water on a farm?
Livestock manure, septic systems, fertilizer, pesticides, fuel, silage leachate and chemical spills can all affect groundwater and surface water. Heavy rain and flooding can carry contaminants into a well, especially if the casing or cap is damaged.
Old, abandoned or unused wells can be a direct path for contamination. Ask your local health department or conservation district about how to have them properly closed by a licensed professional.
Check the casing and cap regularly for cracks, gaps or standing water. A damaged well cap lets insects, rodents and surface water into the well. A licensed well contractor can inspect and repair the well.
What if a test shows a problem?
Do not panic, and do not guess at fixes. Contact your health department or extension office for guidance on what the results mean and what steps to take. In the meantime, ask what water to use for drinking, cooking and brushing teeth, and what to do for infants and people who are pregnant or have weak immune systems.
Treatment systems differ in what they remove, and not every product fits every problem. Talk to a licensed well contractor or water treatment professional, and retest to confirm the fix works.
Do not mix or add chemicals to the well on your own. Disinfection and treatment have steps and safety rules, and doing it wrong can harm you and the system.
How do I handle floods and emergencies?
After a flood, assume well water may be unsafe until it has been tested. Do not drink or use it for food preparation or washing until your health department says it is safe. Follow its advice on disinfecting and retesting the well.
Keep a supply of safe drinking water in your emergency kit. Ask local emergency management and FEMA resources for current guidance.
What about water for animals?
Animals also need clean water. Check troughs and tanks often, clean them regularly and watch for changes in drinking habits or health. Surface water, such as ponds and ditches, can carry algae and germs, so ask your veterinarian or extension office about safe sources.
If your animals become ill and you suspect water, call your veterinarian and your health department.
Key takeaways
- Test your well regularly with a certified lab and after floods, repairs or changes.
- Keep chemicals, fuel, manure and fertilizer away from the wellhead.
- Ask local officials about required distances and well closure rules.
- Get advice before treating or using water after a bad test result.
- Keep animal water clean and assume flood-affected wells are unsafe until tested.
Sources and further reading
Last reviewed: November 12, 2026. Written by the Homestead & Small Farm Editorial Team. See our editorial policy.