Nitrate In Drinking Water In Maine
What residents of Maine need to know about nitrate in drinking water — including how it enters water, which utilities have documented violations, and what steps to take.
Source: EPA SDWIS, Maine Drinking Water Program (Maine CDC / DHHS), CDC · Last reviewed: 2025-01-01
Quick Answer
Is nitrate in drinking water a real concern in Maine?
Lower risk than agricultural states — Maine has limited commercial row-crop agriculture. The primary nitrate concern is septic systems near private wells in rural and suburban communities.
Is this mostly a public-water issue, a private-well issue, or both?
Primarily private well users in communities with high septic system density; Aroostook County potato farming is the main agricultural nitrate source.
What is the main reason residents should care?
Maine's rural character means many households are on private wells and septic systems. Older or failing septic systems near wells are the dominant nitrate source, with Aroostook County potato farming as the primary agricultural contributor.
Key Facts
| EPA Nitrate MCL | 10 mg/L as N |
| Aroostook County | Major potato farming region — primary agricultural nitrate source in Maine |
| Primary concern | Older septic systems near private wells in rural communities |
| Relative risk | Lower than Midwest agricultural states — limited commercial row-crop farming outside Aroostook |
| State oversight | Maine Drinking Water Program (Maine CDC / DHHS) |
Why This Matters in Maine
Maine is one of the least agriculturally intensive states in the continental U.S. The primary exception is Aroostook County — 'The County' — which produces a significant share of the nation's potatoes using substantial fertilizer applications on its thin glacial soils. Outside of Aroostook, Maine's nitrate concern is primarily residential: the state has a high density of private wells and older septic systems in rural communities. Glacial outwash soils in some areas allow relatively rapid percolation from septic leach fields to shallow groundwater. Maine Drinking Water Program monitors public water systems; private well testing is the owner's responsibility. Maine's generally low agricultural intensity means nitrate risk is lower than in farming-intensive states, but private well users in septic-dense areas should still test annually.
Critical — Infants Under 6 Months
Do not use tap water that exceeds 10 mg/L nitrate-nitrogen to prepare infant formula or feed infants under six months. Boiling will concentrate nitrate — do not boil. Use bottled water or a certified reverse osmosis system (NSF/ANSI 58) until the issue is resolved.
Maine Utilities With Nitrate Violation Records
The utilities listed below have at least one nitrate violation on record in EPA's SDWIS database. Violations may be open or resolved — see individual utility pages for current status and risk level.
Kennebunk, Kennebunkport & Wells Wd
Kennebunk,Kennebunkport,Wells · 35,663 served
Bangor Water District
Bangor,Clifton,Eddington,Hampden,Hermon,Orrington,Veazie · 27,298 served
Kennebec Water District
Fairfield,Oakland,Vassalboro,Waterville,Winslow · 22,060 served
Greater Augusta Utility District
Augusta,Chelsea,Manchester,Vassalboro,Winthrop · 13,750 served
How Nitrate Gets Into Drinking Water
Agricultural fertilizer and manure runoff
Nitrogen-based fertilizers and animal waste applied to Maine cropland can leach into groundwater or run off into surface water supplies. This is the dominant nitrate pathway in most agricultural regions.
Septic system effluent
Failing or poorly sited septic systems release nitrogen-rich wastewater near drinking water wells. Rural areas with high well density and aging septic infrastructure face elevated risk.
Concentrated animal feeding operations (CAFOs)
Large livestock facilities generate significant waste. Lagoon leaks and overapplication of manure to nearby fields can create localized nitrate hotspots in groundwater.
Natural geological deposits
In some regions, naturally occurring nitrogen compounds in soil and bedrock contribute background nitrate levels to groundwater independent of agricultural activity.
Who Should Pay Closest Attention
Private well users in Aroostook County near potato farming areas, and rural Maine households with older septic systems adjacent to their wells, should test for nitrate annually. Families with infants should confirm nitrate levels before using well water for formula preparation.
Households with infants under six months
Pregnant residents
Private well owners in agricultural areas
Households near livestock operations or CAFOs
Rural residents on shallow groundwater wells
Households with older or failing septic systems nearby
How to Check Your Situation in Maine
- 1
Identify your water utility. Use the ZIP lookup below or browse the Maine utility directory on this site.
- 2
Read your utility's page on this site to see its current risk level and any open nitrate violations.
- 3
Review your utility's most recent Consumer Confidence Report (CCR) — mailed annually or available on the utility's website. It must disclose any MCL exceedances.
- 4
If you are on a private well, arrange testing at a Maine Drinking Water Program (Maine CDC / DHHS)-certified lab. Your state health department maintains a list of certified labs. Annual testing is recommended in agricultural areas.
- 5
If you have an infant under six months, use bottled water or a certified RO system (NSF/ANSI 58) immediately as a precautionary measure — do not wait for test results if you are in a high-risk area.
- 6
If your utility issues a nitrate exceedance notice, follow their guidance and do not use tap water for infants until the issue is resolved.
Treatment Options
Carbon filters and boiling do not remove nitrate. Only the options below are effective.
NSF/ANSI Standard 58 — Reverse Osmosis
RO systems certified to NSF/ANSI 58 reduce nitrate by 85–95% at the point of use. Under-sink installation required. The most practical residential option for nitrate concerns.
Distillation
Distillation units effectively remove nitrate along with most other dissolved contaminants. Suitable for drinking and cooking water — not whole-house use.
Anion Exchange
Ion exchange systems designed for nitrate removal exchange nitrate ions for chloride on a resin bed. Effective as a point-of-entry system; requires periodic regeneration and monitoring.
Carbon filters do NOT remove nitrate
Standard pitcher filters, faucet filters, and under-sink carbon units — including those certified NSF/ANSI 42 or 53 — do not remove nitrate. Do not use these for nitrate reduction.
Frequently Asked Questions
Related Pages
Nitrate — National Overview
All U.S. utilities with nitrate records
Maine State Overview
All utilities and water quality data
Lead in Drinking Water
A separate but common concern
Reverse Osmosis Guide
Removes 85–95% of nitrate
Well Water Guide
Private well testing and safety
All Contaminants
Complete reference library
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.
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Maine Drinking Water Program (Maine CDC / DHHS) ↗