Well water testing in Hillsborough County, New Hampshire

Last verified: 2026-10-25 · 12 sources · What we couldn't verify

Arsenic and PFAS are the headline risks: a random USGS sample found 21% of Hillsborough County bedrock wells over the 10 µg/L arsenic standard, and Saint-Gobain's Merrimack plant contaminated wells across parts of Bedford, Hudson, Litchfield, Manchester and Merrimack. The state lab charges $95-$120 for its standard analysis; PFAS sampling is free inside the Saint-Gobain area and free for prioritized wells elsewhere through NHDES.

NHDES says private wells supply about 46% of New Hampshire's population. In the three southeastern counties (Hillsborough, Rockingham and Strafford), USGS reports that about 39% of residents used private wells in a 2005 water-use study. There is no statewide testing requirement, but some towns require testing for a certificate of occupancy; a 2021 NHDES presentation listed Pelham (Hillsborough County) among them and noted that Goffstown requires water to meet standards to be considered potable. Check with your town for current rules.^[2][10]

Free and low-cost testing programs

Labs that serve the county

NHDES's lab list was last updated 9/20/2024. Accreditation is per test, so confirm with NHDES's Accredited Laboratory Search (NHELAP: (603) 271-2998 / (603) 271-5314, nhelap@des.nh.gov) that a lab is accredited for every test you need.^[1]

Local contaminants of concern

• Major concern Arsenic. In a USGS study of randomly selected private bedrock wells, 32% of 158 Hillsborough County samples had more than 5 µg/L arsenic, 21% more than 10 µg/L (the EPA standard) and 3% more than 50 µg/L; the highest was 75 µg/L. Statewide, 25% of wells tested at the state lab (2006 - Aug 2020) exceeded 5 µg/L.^[9][2]
• Major concern PFAS (PFOA and related). PFAS from Saint-Gobain's Merrimack plant spread largely through air emissions. Saint-Gobain has sampled about 2,600 properties inside the Consent Decree area and found nearly 1,200 over state water-quality standards. Elsewhere, NHDES says PFAS have affected wells throughout the state, especially in the south, and recommends all well owners test for PFOA, PFOS, PFHxS and PFNA.^[11][5][1]
• Major concern Radon in water. Statewide, 30% of wells tested at the state lab exceeded the 2,000 pCi/L radon testing advisory. We did not find a primary-source Hillsborough County rate.^[2]
• Moderate concern Manganese and iron. In a 2012-13 USGS random sample of 232 bedrock wells in Hillsborough, Rockingham and Strafford Counties, 5.2% exceeded the 300 µg/L manganese health advisory, 26.7% exceeded the 50 µg/L manganese aesthetic guideline and 16.8% exceeded 300 µg/L iron.^[10]
• Moderate concern Sodium and chloride (road salt). Statewide, 34% of wells tested at the state lab exceeded 20 mg/L sodium and 3% exceeded 250 mg/L chloride.^[2]
• Moderate concern Lead and copper (plumbing). Statewide first-draw samples: 13% exceeded 0.015 mg/L lead and 12% exceeded 1.3 mg/L copper (2% and 1% after flushing). In the USGS three-county sample, 3% exceeded the 15 µg/L lead action level.^[2][10]
• Lower concern Uranium. 2.6% of the USGS three-county sample exceeded the 30 µg/L uranium standard; 4% statewide in state lab data.^[10][2]
• Lower concern Nitrate / nitrite and bacteria. Statewide, essentially no wells tested at the state lab exceeded 10 mg/L nitrate (0%) or 1 mg/L nitrite. No county bacteria rate was in our sources; NHDES still recommends testing bacteria, nitrate and nitrite every year.^[2][1]

The USGS arsenic figures come from randomly selected wells (2003 fact sheet); the statewide figures are wells whose owners chose to test at the state lab, which can skew toward problem wells. A Hillsborough-only breakdown of the state lab data is on the NH DHHS Private Well Water Quality Dashboard, which we could not read automatically.

A county rate can't tell you what's in your well. Only a test can. See what to test for.

Typical cost

Prices are from the published lists cited, as of the last-verified date. Confirm before ordering.

How often to test

• Every year: bacteria (total coliform and E. coli), nitrate and nitrite.^[1]
• Every 3-5 years: arsenic, chloride, copper and lead (stagnant and flushed), fluoride, hardness, iron, manganese, pH, radon, sodium, uranium, and PFAS (PFHxS, PFNA, PFOA, PFOS).^[1]
• PFAS: if a first test finds none and budget is tight, NHDES says waiting longer is acceptable if nearby land use does not change.^[1]
• Home buyers: test before buying if the seller has no recent test. After installing treatment: test treated water, then every 3-5 years.^[1]

How to collect a sample

Steps from the NH state lab's Standard Analysis kit (private labs have their own instructions):

1. If you recently disinfected the well, make sure all chlorine is gone. Use a clean indoor cold-water faucet that does not leak; do not touch the inside of bottles or caps.
2. Let water sit in the pipes at least 6 hours (overnight is best), then immediately fill the small "First Draw for Lead/Copper" bottle.
3. Remove the aerator if possible, clean the faucet rim with dilute bleach (1 capful per cup of water), and run the water for 1 minute.
4. At a gentle stream, fill the sterile bacteria, nitrate/nitrite and non-sterile bottles. For radon, slowly fill the glass vial to a crown, cap it, and check upside down for bubbles (refill if any).
5. Keep samples cold (not frozen) and deliver ASAP: bacteria within 30 hours, radon and nitrate/nitrite within 48 hours.

Source^[3]. General steps: How to test your well water.

After you get results

Enter your results into NHDES's Be Well Informed web tool for health information and the treatment type that addresses each result. If PFAS is over a standard and you are outside the Saint-Gobain area, the NHDES rebate above can cover up to $5,000 of treatment.^[1][6]

What we couldn't verify

• A Hillsborough County radon rate and county breakdowns of the state lab data (the NH DHHS dashboard is interactive and we could not read it).
• Nelson Analytical shows two different price lists online: its kit order form (Standard $80, Comprehensive $150) and an older-looking price list (Standard $65, Comprehensive $125). We show the order-form prices; confirm when ordering.
• Mail-in policies for Nelson Analytical and Eastern Analytical, and Eastern Analytical's prices.
• Whether Nashua or Manchester city health departments offer any well-testing help; we found none.
• Current (2026) list of towns requiring well testing for occupancy; the source is a 2021 NHDES presentation.

Sources

1. NH Department of Environmental Services: Water Testing Guidance for Private Well Users (April 2026; lab list updated 9/20/2024)
2. B. Kernen, NHDES (hosted by City of Portsmouth): Private Wells in Portsmouth (presentation, Sept. 1, 2021; EPHT combined NHDES/NH PHL data 2006 - Aug 2020)
3. NH DHHS Public Health Laboratories: Water Test Submittal Form & Water Testing Guide / Sample Collection Instructions
4. NH DHHS: Water Analysis Laboratory Program
5. NHDES PFAS Response: Private Wells (PFAS testing)
6. NHDES PFAS Response: PFAS Removal Rebate Program for Private Wells
7. Granite State Analytical: Residential Services (test packages and prices)
8. Granite State Analytical: Drop-Off Locations
9. U.S. Geological Survey: Arsenic Concentrations in Private Bedrock Wells in Southeastern New Hampshire (Fact Sheet 051-03, 2003), table 1
10. U.S. Geological Survey: Arsenic, Iron, Lead, Manganese, and Uranium Concentrations in Private Bedrock Wells in Southeastern New Hampshire, 2012-2013 (Fact Sheet 2014-3042)
11. NHDES PFAS Response: Saint-Gobain Performance Plastics (investigation, well sampling and alternate water)
12. Nelson Analytical Lab: Request Sample Test Kits (price list and lab locations)

All sources accessed on or before 2026-10-25.

More useful links

• NHDES private wells page (links to the Be Well Informed tool)
• NHDES Saint-Gobain well sampling page

Other New Hampshire counties

• Rockingham County

All New Hampshire county guides