Well Water in Oxford County, Maine
Oxford County · Population ~58,000 (county) · Aquifer: Bedrock / Androscoggin River Valley
Oxford County in western Maine is rural, heavily forested, and almost entirely dependent on private wells. The county's geology — predominantly granitic and pegmatitic bedrock — produces some of the highest arsenic and uranium concentrations found in Maine wells. This is the same geology that makes western Maine famous for its mineral specimens.
The Granite Belt
Oxford County sits in the heart of Maine's granite belt. The same pegmatite formations that produce tourmaline, beryl, and other gemstones also contain arsenic and uranium-bearing minerals. As groundwater moves through fractures in this bedrock, it dissolves these naturally occurring contaminants.
The Maine Geological Survey has documented arsenic concentrations above 10 µg/L (the EPA standard) in a significant percentage of Oxford County wells. Unlike industrial contamination, this is natural — it's been there for millions of years. But "natural" doesn't mean safe.
Uranium and Radon
The same granitic geology that produces arsenic also produces uranium and radon. These three contaminants frequently co-occur in Oxford County wells because they share geological source materials.
- Uranium — long-term exposure affects kidneys and increases cancer risk. EPA limit: 30 µg/L.
- Radon — dissolved in well water, released into indoor air during water use. A known lung cancer risk.
If your well tests high for arsenic, you should also test for uranium and radon. The geology that produces one often produces all three.
Rural Well Challenges
Oxford County is one of Maine's most rural counties. Many wells are old, some are shallow dug wells rather than modern drilled wells, and professional water testing services may require longer travel times.
Older, shallower wells are more vulnerable to bacteria contamination and may not have proper well caps or casing to prevent surface water from entering. If your well was dug rather than drilled, consider having a well professional inspect the construction in addition to testing the water.
Testing Priorities
Every Oxford County well should be tested for arsenic (free through Maine CDC), uranium, and radon at minimum. A full panel should also include manganese, bacteria, nitrate, pH, and hardness.
See our testing guide for labs and free testing options.
Every well is different. Two wells on the same street can produce completely different water. The data on this page reflects documented conditions in the Oxford County area, but the only way to know what's in your water is to test it.
Sources
- Maine Geological Survey — Arsenic in Maine Groundwater
- Maine Geological Survey — Bedrock Geology of Oxford County
- USGS — Uranium in Ground Water of New England
- Maine CDC — Private Well Water Testing