# How to plan well water testing

Choose a laboratory panel and know when routine testing is not enough.

Updated 2026-11-10. Also on the [web page](https://welldrillers.fyi/guides/well-water-testing).

## Set a routine baseline

CDC and EPA recommend testing private well water at least annually for total coliform bacteria, nitrates, total dissolved solids and pH. Ask the local health department which other contaminants need testing in your area. A clear appearance does not replace laboratory results.

Use a laboratory certified for the tests you need. In Canada, use the laboratory service and guidance named by your provincial or local health authority. Ontario recommends testing at least three times a year, including spring and fall. The US annual baseline does not replace that provincial guidance.

## Test when conditions change

CDC and EPA identify flooding, well repairs and changes in taste, smell or colour as reasons to test outside the routine schedule. CDC also identifies pregnancy and a child starting to live in the home. Contact the health department promptly if these apply. Do not wait for the next annual reminder.

## Ask before collecting

Tell the laboratory whether the sample is from the raw supply or after treatment. Ask for the correct bottles, sampling point, handling instructions and delivery deadline. Follow the laboratory's directions. Do not rinse prepared sample bottles or choose a collection method from memory.

Tell the health department about farming, septic systems, fuel storage, nearby industrial activity and any known local problem. EPA's page links these conditions with extra tests to consider. Do not buy every available test without a reasoned panel.

## Read and retain results

Keep the full report, sample location, collection date and laboratory details. Compare the same sampling point over time. Ask the health department to interpret abnormal results and advise on treatment, further tests or a safe alternative supply. CDC advises using bottled water or another safe source when harmful germs or chemicals are found.

Our schedule planner gives a US annual reminder and flags events that need attention now. It cannot certify water as safe. A negative bacteria test does not rule out chemical contamination.

## Sources

- [CDC, Guidelines for Testing Well Water](https://cdc.gov/drinking-water/safety/guidelines-for-testing-well-water.html). Fetched 2026-11-10.
- [US EPA, Protect Your Home’s Water](https://www.epa.gov/privatewells/protect-your-homes-water). Fetched 2026-11-10.
- [Ontario, Wells on your property](https://www.ontario.ca/page/wells-your-property). Fetched 2026-11-10.

## Questions

### Does this replace local advice?

No. Confirm the work with the responsible agency and a qualified contractor.