Well water in Hollis, Maine
In Hollis, 43% of 133 private wells tested had arsenic above the Maine guideline (10 ug/L), according to Maine CDC.
155 private wells tested in state summaries; 6 individual samples from 5 wells, 1961 to 2007. Data refreshed September 3, 2026.
What homeowner tests found
Maine Tracking Network private well summaries: private wells tested and reported to the state. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA.
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What this means
Among homeowners in Hollis who sent a sample to the state lab, the health-based limits most often exceeded were arsenic (43% of 133 wells), uranium (7% of 98 wells), and fluoride (4% of 155 wells). These are ordinary wells tested by their owners, so the shares are the best available picture of a typical well here, with one caveat: people test more often when they suspect a problem.
What to test for in Hollis
- Volatile organic compounds (VOCs)3 leaking underground storage tank sites on record locally.
- PFAS2 unlined landfills on record locally.
- Arsenic43% of 133 local wells tested were above the Maine guideline.
- Uranium7% of 98 local wells tested were above the Maine guideline.
- Fluoride4% of 155 local wells tested were above the Maine guideline.
- Manganese<1% of 109 local wells tested were above the Maine guideline.
- Coliform bacteriaRecommended for every private well, every year.
- ChlorideDetected in 100% of local samples.
- IronDetected in 100% of local samples.
- NitrateRecommended for every private well, especially near farms or septic systems.
Wells in Hollis
454 domestic wells in Hollis are on record with the state since 1970. 95% are drilled into bedrock, and the typical well is 280 feet deep (one in ten goes past 500 feet).
In a typical Hollis well, bedrock starts about 28 feet down, the median yield is 8 gallons per minute, 19% of wells yield under 3 gallons per minute and usually need a storage tank.
Bedrock wells are where arsenic, uranium and radon come from: the water sits in fractures in granite and metamorphic rock and picks up whatever the rock carries. That is why testing for those three matters more here than in a dug or gravel well.
Contamination sources on record in Hollis
Maine DEP records 3 leaking underground storage tank sites and 2 unlined landfills in Hollis, among 8 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.
- 3
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 2
- unlined landfillsOlder unlined landfills are a leading source of PFAS, VOCs and metals in nearby wells.
- 3
- other remediation projects
Treatment that fits the local profile
- Arsenic
- Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
- Uranium
- Point-of-use reverse osmosis; Anion exchange; Whole-house anion exchange
- Chloride
- Point-of-use reverse osmosis; Distillation
- Iron
- Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
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Common questions
How deep are wells in Hollis?
The typical domestic well in Hollis is 280 feet deep, based on 454 wells reported to the state since 1970. One in ten is deeper than 500 feet. 95% are drilled into bedrock.
Is there arsenic in well water in Hollis?
Arsenic was detected in 100% of 3 public well samples in Hollis, and 100% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.
How often should I test a private well in Hollis?
Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.
Sources
- USGS Water Quality Portal: 16 samples in Hollis. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
- Maine Tracking Network private well summaries: summaries for 6 contaminants in Hollis, up to 155 wells each. Town summaries of private well tests run by the Maine Health and Environmental Testing Laboratory, published by Maine CDC through the Maine Tracking Network. Shares are against Maine's guideline for each analyte (arsenic 10 ug/L, uranium 30 ug/L, fluoride 2 mg/L, manganese 0.3 mg/L, nitrate 10 mg/L, nitrite 1 mg/L). Towns with too few tests are suppressed (NR). Only the share above the guideline and wells tested are published; no medians. Retrieved September 3, 2026.
- Maine Geological Survey well database: 470 well records in Hollis, 454 domestic. Well construction records reported to the Maine Geological Survey by licensed well drillers. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 3, 2026.
- Maine DEP regulated sites: 8 regulated sites located in Hollis. Remediation sites, leaking underground storage tanks and closed municipal landfills from the Maine Department of Environmental Protection. Retrieved September 3, 2026.
Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.