Nitrate exposure in drinking water is tracked by EPA across the country; households in South Yarmouth, Massachusetts are among those with confirmed detections in the public water record.

Data: EPA SDWIS, CCR Reports, ECHO Last verified: 2026-06-04

Nitrate in South Yarmouth Tap Water

Nitrate has been detected in South Yarmouth, Massachusetts drinking water at a maximum level of 6.4 ppb — below the EPA MCL of 10 mg/L (as nitrogen).

This analysis covers 9,720 residents across 1 ZIP code in South Yarmouth.

South Yarmouth's overall water quality grade is B (73/100).

Is Nitrate in South Yarmouth Water Safe?

Nitrate was detected in South Yarmouth water but currently falls within EPA limits. However, some health organizations argue the EPA MCL may not be protective enough.

If you are concerned, a reverse osmosis or ion exchange filter can reduce nitrate levels further.

Nitrate Levels by ZIP Code

Average nitrate level across South Yarmouth: 6.4 ppb

Health Effects of Nitrate

• Methemoglobinemia ("blue baby syndrome") in infants under 6 months
• Increased risk of colorectal and bladder cancer (long-term)
• Thyroid disease from chronic exposure
• Possible reproductive effects

Health risk severity: High. Governed by the National Primary Drinking Water Regulations.

How Nitrate Gets Into Drinking Water

• Agricultural fertilizer runoff
• Animal feedlot operations and manure
• Septic system leachate
• Urban stormwater and wastewater discharge

What to Do About Nitrate in South Yarmouth Water

1. Reverse osmosis is the most effective method for nitrate removal
2. Ion exchange systems designed for nitrate can also work
3. Standard carbon filters do NOT remove nitrate
4. Boiling water increases nitrate concentration — never boil for nitrate

Look for filters certified under NSF 53 / NSF 58 for nitrate removal.

Related

• Nitrate — National Overview
• Nitrate in Massachusetts
• Massachusetts Water Quality
• South Yarmouth Water Quality
• Check Your ZIP Code