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Best way to test well water
Most well testing goes through one of four routes: a state lab, your county health department, a certified commercial lab, or a kit you mail to a lab. What matters most is that the lab is certified for each test and that the sample is taken correctly. Every claim below has a source.
Use a certified or accredited lab
- CDC says to test your well at least once a year for total coliform bacteria, nitrates, total dissolved solids and pH.1 PA DEP gives the same yearly list and says to always use a state-certified laboratory for drinking water tests.2
- Labs are accredited test by test. Maine CDC says it's necessary to check with a lab to find out exactly what it's accredited for, and that this can change.3
- Maine CDC lists the benefits of an accredited lab as known testing methods, recognized quality control, and access to state accreditation officers who can help with questions about your results.4
The four routes
| Route | Examples from our sources |
|---|---|
| State lab | Maine's Health and Environmental Testing Laboratory offers private well kits.5 New Hampshire's Public Health Laboratories appear on NHDES's accredited lab list.6 Michigan's EGLE Laboratory takes requests from well owners.8 |
| County or local health department | Some health departments test well water themselves. EGLE lists Michigan departments with onsite testing,8 Genesee County, MI tests for bacteria,9 and Union County, NC offers well sampling and testing.10 |
| Certified commercial lab | Every state we cover publishes an official list: NH (NHELAP search), Maine CDC's lab list, PA DEP's lab PDFs, and county lists like Livingston County, MI's.63211 |
| Mail-in kit to a lab | If you ship samples, Livingston County, MI links a video on packing them for thermal preservation.11 Maine CDC recommends checking that a lab can receive bacteria samples within the holding time from your area.3 |
A university lab can also help. Penn State's Agricultural Analytical Services Laboratory offers test packages for well and spring owners.12
What a full panel should include
A first test should cover your state's whole recommended list. Here's NHDES's list as an example of a thorough one: arsenic, bacteria (total coliform and E. coli), chloride, copper, fluoride, hardness, iron, lead, manganese, nitrate, nitrite, pH, radon, sodium, uranium, and four PFAS (PFHxS, PFNA, PFOA, PFOS).6 Maine CDC recommends a comprehensive test for its full list if you've never tested.4
Add tests based on where you live: county data (see our county pages) and anything near your well, such as farms, fuel tanks, or a PFAS investigation area.
How to take a sample that means something
- Bacteria: Livingston County, MI's instructions say to remove the aerator if you can, disinfect the faucet tip, run cold water for 15–20 minutes, fill the bottle without touching the inside or the lid (leave any pill or powder in it), and keep it chilled until it reaches the lab.11
- Lead and copper: NHDES recommends both stagnant and flushed samples.6
- Untreated vs. treated: if you have treatment, decide what you're testing. NHDES says buyers can test after treatment to check the treated water, and owners should test treated water after installing a system.6
- Follow the lab's bottle instructions. Bacteria samples in particular have to reach the lab within a holding time.3
After you get the report
- Compare each result to the standard listed on the report, and see how to read your well water test results.
- New Hampshire and Michigan point well owners to the Be Well Informed tool to interpret results.78
- EGLE recommends contacting your local health department with questions about your results and what to do.8
Where to get tested and treatment options
Related guides
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CDC, "Guidelines for Testing Well Water." https://www.cdc.gov/drinking-water/safety/guidelines-for-testing-well-water.html ↩
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Pennsylvania DEP, "Private Wells: Water Testing." https://www.pa.gov/agencies/dep/residents/my-water/private-wells/water-testing ↩↩
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Maine CDC, "Maine In-State Commercial Drinking Water Labs" (PDF, updated 5/16/2026). https://www.maine.gov/dhhs/mecdc/sites/maine.gov.dhhs.mecdc/files/CommercialListMaineLabs.pdf ↩↩↩↩
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Maine CDC, "Private Well Water." https://www.maine.gov/dhhs/mecdc/healthy-living/health-and-safety/drinking-water-safety/private-well-water ↩↩
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Maine CDC HETL, "HETL Water Testing Kits Available" (PDF). https://www.maine.gov/dhhs/mecdc/sites/maine.gov.dhhs.mecdc/files/Environmental%20Test%20Guide.pdf ↩
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NHDES, "Water Testing Guidance for Private Well Users" (April 2026). https://www.des.nh.gov/sites/g/files/ehbemt341/files/documents/labs-private-wells.pdf ↩↩↩↩↩
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NHDES, "Private Wells." https://www.des.nh.gov/water/drinking-water/private-wells ↩
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Michigan EGLE, "Private Residential Water Well Testing." https://www.michigan.gov/egle/about/organization/drinking-water-and-environmental-health/water-well-construction/private-well-testing ↩↩↩↩
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Genesee County, MI, Health Department, "Wells: Planning, Permits, Bacteria Testing." https://www.geneseecountymi.gov/departments/health_department/eh/wells.php ↩
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Union County, NC, Environmental Health, "Wells and Water Testing." https://www.unioncountync.gov/government/departments-a-e/environmental-health/wells-and-water-testing ↩
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Livingston County, MI, Environmental Health, "Water Quality Testing for Wells." https://milivcounty.gov/environmental-health/wells/water-quality/ ↩↩↩
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Penn State Extension, "County Summaries of Pennsylvania Groundwater Well and Spring Data." https://extension.psu.edu/county-summaries-of-pennsylvania-groundwater-well-and-spring-data ↩