How often should I test my well water in Knox County, Maine?

Maine CDC recommends testing private wells every year for bacteria and nitrates, and every 3 to 5 years for a full panel including arsenic, uranium, radon, and lead.

Where can I drop off a water sample in Knox County?

Chanalytical Laboratories has 7 drop-off locations across Maine; the nearest to Knox County are listed on this page. Most results are delivered the next business day.

Private well water testing — Knox County, Maine

More than half of Maine households rely on private wells, and no one is required to test a private well but its owner. Here's what applies in Knox County, where to drop a sample, and a free 60-second checkup that turns the guidance into your own plan.

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What Maine recommends for every private well

Every year: bacteria (total coliform / E. coli) and nitrate/nitrite — Maine CDC.
Every 3–5 years: a full panel including arsenic, uranium, radon, lead, manganese, fluoride, and pH — Maine CDC. About 1 in 10 Maine wells has arsenic above the federal limit, with no taste, smell, or color.
After events: retest after flooding, well or pump work, or any change in taste, smell, color, or staining.
Transactions: FHA requires coliform, nitrate, nitrite, and lead; VA/USDA follow the local health authority. Maine sellers disclose the date of the last test (33 M.R.S. §173). Rental wells need an arsenic test every 5 years (22 M.R.S. §2660-Y).

Area-level information cannot determine what is in a specific household's well — neighboring wells can test differently. Only a properly collected laboratory sample can tell you what's in your water. This page is educational; see the disclaimer.

What testing has historically found in Knox County

Arsenic: 16.7% of 798 tested wells were above the guideline (10 µg/L)
Uranium: 2.4% of 548 tested wells were above the guideline (30 µg/L)

Statewide, about 1 in 10 tested wells exceeds the arsenic guideline. Figures are from wells whose owners chose to test through the state lab (Maine Tracking Network / Maine HETL, data updated 5/2023) — area-level context from a voluntary sample, not a prediction about any individual well. Neighboring wells can differ completely; only a properly collected sample tells you what's in yours. Source: Maine Tracking Network

Coastal towns: saltwater intrusion (chloride/sodium) can be a consideration for wells near the shore.

Nearest sample drop-off locations

The Mailing Center — 126 Western Ave., Augusta, ME · Directions
Dysart's Restaurant & Truck Stop — 530 Colebrook Rd., Hermon, ME 04401 · Directions

Bacteria samples must reach the lab within about 30 hours of collection — collect on a weekday morning and drop off the same day. Confirm timing: (207) 747-1815.