Nitrate In Drinking Water In Massachusetts
What residents of Massachusetts 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, Massachusetts Department of Environmental Protection (MassDEP), CDC · Last reviewed: 2025-01-01
Quick Answer
Is nitrate in drinking water a real concern in Massachusetts?
Moderate — Massachusetts has limited commercial agriculture. The primary nitrate concern is suburban septic systems near private wells, with Cape Cod having a well-documented nitrate issue from very high septic system density on sandy soils.
Is this mostly a public-water issue, a private-well issue, or both?
Primarily private well users in suburban areas with older or high-density septic systems; Cape Cod's sole-source aquifer is the most documented nitrate concern in the state.
What is the main reason residents should care?
Cape Cod's sandy soils and sole-source aquifer — combined with one of the densest per-capita concentrations of septic systems in New England — create documented nitrate elevation in the aquifer that supplies Cape communities.
Key Facts
| EPA Nitrate MCL | 10 mg/L as N |
| Cape Cod aquifer | Sole-source aquifer with documented nitrate from dense septic system effluent on sandy soils |
| Primary source | Residential septic systems — agricultural nitrate is limited in Massachusetts |
| At-risk communities | Cape Cod, and other suburban MA communities with older high-density septic systems |
| State oversight | Massachusetts Department of Environmental Protection (MassDEP) |
Why This Matters in Massachusetts
Massachusetts has limited row-crop agriculture, so agricultural nitrate pathways are less dominant than in Midwest states. However, Cape Cod represents a significant exception: the Cape relies entirely on a sole-source aquifer for drinking water, and its sandy soils provide minimal filtration for the large volume of nitrogen-rich effluent from the Cape's many thousand septic systems. Several Cape communities — Barnstable, Falmouth, Chatham — have documented elevated nitrate in groundwater. MassDEP monitors public water systems for nitrate compliance. Private well users on Cape Cod and in other high-septic-density suburban Massachusetts communities should test annually.
Historical Context
Cape Cod's sole-source aquifer has been the subject of extensive nitrogen management efforts, including a Cape Cod Regional Policy Plan requiring municipalities to address septic system nitrogen loading. The issue is driven almost entirely by residential septic density rather than agriculture.
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.
Massachusetts 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.
Worcester Dpwp, Water Supply Division
Worcester · 206,518 served
Cambridge Water Department
Cambridge · 118,214 served
Brockton Water Department
Brockton · 105,643 served
Inima Usa / Aquaria Llc
Dighton · 105,643 served
Fall River Water Department
Fall River · 94,000 served
Lawrence Water Works
Lawrence · 88,877 served
Malden Water Division (mwra)
Malden · 66,263 served
Taunton Water Division
Taunton · 62,165 served
Peabody Water Dept.
Peabody · 54,481 served
Plymouth Water Department
Plymouth · 46,799 served
How Nitrate Gets Into Drinking Water
Agricultural fertilizer and manure runoff
Nitrogen-based fertilizers and animal waste applied to Massachusetts 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 on Cape Cod and in other Massachusetts suburban communities with high septic system density should test for nitrate annually. Seasonal residents returning to Cape Cod wells after extended non-use periods should flush and test before relying on the water.
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 Massachusetts
- 1
Identify your water utility. Use the ZIP lookup below or browse the Massachusetts 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 Massachusetts Department of Environmental Protection (MassDEP)-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
Massachusetts 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.