Well water testing in Naples, Maine
If your Naples home is on a private well, testing is up to you. Maine doesn't regulate private wells. Below is what the state lab found when 149 Naples well owners tested for arsenic, where to drop off a sample, and a free 60-second checkup.
Take the free checkup for your Naples home →
What the state lab found in Naples wells
Uranium: 55.8% of 163 tested wells in Naples were above Maine's guideline. That is about 3 times the Cumberland County rate (19.8%). The middle result was 40 µg/L, and 1 in 20 tested wells came in at 610 µg/L or higher. Comes from bedrock, often granite. No taste or smell.
None of the 149 Naples wells tested for arsenic were above the guideline, compared with 17.3% across Cumberland County.
| Tested for | Wells tested | Above Maine's guideline | Maine's guideline |
|---|---|---|---|
| Uranium | 163 | 55.8% | 30 µg/L |
| Fluoride | 186 | 4.3% | 2 mg/L |
| Chloride | 70 | 1.4% | 250 mg/L |
| Arsenic | 149 | 0% | 10 µg/L |
| Manganese | 143 | 0% | 0.3 mg/L |
| Nitrate | 164 | 0% | 10 mg/L |
Wells whose owners chose to test at Maine's state lab (HETL): a voluntary sample, not a prediction about any one well. Neighbors can test very differently. No rate is shown when fewer than 20 wells were tested. Source: Maine Tracking Network (Maine CDC), data updated 5/2023
Not in this data: bacteria and radon in water. Maine does not publish those results by town or county. Maine CDC still recommends testing every well for bacteria every year and for radon every 3 to 5 years.
PFAS in Naples
Maine DEP has sampled 10 private wells tied to PFAS investigation sites in Naples. None were above 20 parts per trillion for six PFAS combined, the level DEP reports against. DEP chose these wells because they were near sites it was checking, so the results are not a picture of every well in town.
Source: Maine DEP, PFAS private well results by town (preliminary; DEP is still adding results; read November 2026).
What Maine recommends for every well
Maine CDC says to test every private well each year for bacteria and nitrate, and every 3 to 5 years for a full panel that includes arsenic, uranium, radon, and lead. Retest after flooding, well or pump work, or any change in taste, smell, or color. The Cumberland County page has the full schedule and the rules for home sales and rentals.
Area-level information cannot determine what is in a specific household's well. Only a properly collected laboratory sample can tell you what's in your water. This page is educational; see the disclaimer.
Coastal towns: saltwater intrusion (chloride/sodium) can be a consideration for wells near the shore.
Nearest sample drop-off locations to Naples
- Plummer's / Ace Hardware — 57 Main St., Gorham, ME · Directions
- Focused Property Inspections — 347 Main St., Unit 2G, Gorham, ME 04038 · Directions
- Chanalytical Laboratories (24-hr drop-box) — 347 Main St., Unit 1B, Gorham, ME 04038 · Directions
- Fontus — 39 Immersion Dr., Suite 3, Scarborough, ME · Directions
- Ward Water / Critical Plumbing — 1150 Pequawket Trail, Steep Falls, ME · Directions
- A-Z Water Systems — 1164 Lewiston Rd., New Gloucester, ME 04260 · Directions
- Mallet Springs Water Company — 361 Bath Rd., Brunswick, ME 04011 · Directions
Bacteria samples must reach the lab within about 30 hours of collection. Confirm timing: (207) 747-1815.
Buying or selling in Naples?
FHA loans require a water test for coliform, nitrate, nitrite, and lead; VA and USDA follow the local health authority. Maine sellers must disclose the date of the last water test. The checkup has a transaction mode that walks through it.