County water report

Rockingham County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Rockingham County, New Hampshire.

Water grade

Water score

26.4

State rank

of 10

Health violations

164

EPA SDWIS, 5-year lookback

Watershed impaired

0.0%

1 water bodies assessed

Monitoring sites

464

54,792 recent measurements

Live streamflow

44%

EXETER RIVER AT HAIGH ROAD, NEAR BRENTWOOD, NH

Water at a glance

Key Water Indicators for Rockingham County

EPA SDWIS

Safety Grade

Score: 26.4 / 100

EPA SDWIS

Active Violations

164

5-year health-based lookback

EPA ATTAINS

Watershed Health

0% impaired

1 bodies assessed

USGS NWIS

Streamflow Snapshot

44% of mean

EXETER RIVER AT HAIGH ROAD, NEAR BRENTWOOD, NH

EPA WQP

Monitoring Sites

464

54,792 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

26.4/100

Health violations

164

Health-based violations

Violations per 100K served

82.5

Population-normalized SDWIS rate

Data center water stress

Rockingham County has 4 facilities in the DCWSI dataset.

ByCounty's DCWSI ranks this county #990 nationally by combining its water score with mapped data center density.

DCWSI

43.0

0-100 index

Facility count

67.8 density percentile

Discharge estimate

Not reported

EPA CWA fields where available

Water vs median

-23.6

Compared with US county median

Named operators

Phillips Exeter AcademyFirstLight

Mapped facilities

Information Technology Data Center
Phillips Exeter Academy
OSM
LIBERTY MUTUAL DATA CENTER
PORTSMOUTH
EPA ECHO
OpenStreetMap data center 87058670
Portsmouth · FirstLight
OSM
ROBERT HOOKE HOLDINGS, LLC
SALEM
EPA ECHO

See the Rockingham County data-center report Review methodology

Data Center Water Budget Calculator

Estimate daily water use for a hypothetical facility in Rockingham County.

Facility size: 100 MW

1 MW1,000 MW

Cooling type

Utilization: 70%

40%100%

799K gallons/dayModerate Impact

Your facility would use 11.9% of this county's industrial water baseline — manageable but worth monitoring against drought trends.

11.9% of county industrial baseline5.90 Mgal/day remaining headroom

Based on USGS 2020 water-use data and EPA-standard cooling intensity constants. Not a substitute for site-specific water rights analysis.

Editorial analysis

Understanding Rockingham County’s Water

Drinking Water Quality Overview

EPA SDWIS

Rockingham County's water systems carry a failing grade, scoring 26.4 out of 100. Over the past five years, EPA SDWIS records 164 health-based violations — a pattern that public water utilities are required to disclose and correct.

Watershed Conditions

EPA ATTAINS

Under the Clean Water Act §303(d), EPA ATTAINS tracks whether waterways meet quality standards for drinking, recreation, and aquatic life (reporting cycle: 2022). None of the assessed waterways are listed as impaired (0 of 1 water bodies) across Rockingham County's watersheds. Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T14:15:00.000-04:00) puts EXETER RIVER at 47.7 cfs — well below its long-term average at 44% of mean — low-flow conditions worth noting for water-dependent ecosystems. Streamflow is a leading indicator of drought stress, sediment load, and dilution capacity: low flows concentrate pollutants and warm water temperatures, stressing aquatic life and, in surface-water-dependent systems, the source water quality for treatment plants.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Rockingham County has extensive coverage with 464 active monitoring sites with 54,792 recent measurements on record. Predominant monitoring categories include physical and microbiological. More monitoring sites generally indicate greater scientific attention to local water conditions — and provide the baseline data that regulators use to set future impairment listings.

Editorial advisory

What the data suggests for Rockingham County

Water Verdict

Rockingham County receives a poor water quality assessment with a grade of F and a score of 26.4 out of 100. The water supply has documented quality issues. Residents are strongly encouraged to use filtered or bottled water for drinking and to stay informed about utility improvement plans.

Violation Context

Rockingham County has recorded 164 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 82.5 violations per 100,000 people served, this rate is high and signals significant water quality management issues.

Consumer Guidance

Rockingham County has a Grade F compliance record with 164 health-based violations — among the highest levels in the country. Rockingham County's drinking-water compliance score is 26.4 out of 100. The violation rate for Rockingham County is 82.5 per 100,000 people served. Residents are strongly advised to use a certified NSF 58 reverse-osmosis filter or bottled water for all drinking and cooking until violations are corrected. Contacting the New Hampshire Department of Environmental Quality or Health can expedite utility compliance action. With 464 active water-quality monitoring sites in Rockingham County, data coverage is strong. A pipeline streamflow snapshot from the EXETER RIVER gauge is also available on this page.

Regional Context

Rockingham County has poorer water quality than the average county in New Hampshire. Its water score is 6.8 points lower than the state average, suggesting more challenges with contamination control or infrastructure than neighboring counties.

Advisory text summarizes county-level public records and is not a replacement for your utility's current Consumer Confidence Report or direct local notices.

Contaminants & Resources

Key issues flagged in Rockingham County's water environment

Official EPA Resources for Rockingham County

EPA How's My Waterway

Interactive watershed health data for Rockingham County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Rockingham County

Consumer Confidence Reports (NH)

Annual water quality reports from utilities in New Hampshire

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

0.0%

0 of 1 assessed

Mostly healthy

Top Impairment Causes

No specific impairment causes reported for the assessed water bodies in this county.

Source: EPA ATTAINS · Reporting cycle 2022

Impairment is determined under the Clean Water Act §303(d): a water body is impaired when it fails to meet state-defined quality standards for designated uses (drinking, recreation, aquatic life). Assessment coverage varies by state; counties without assessed water bodies are not shown.

Past 5 years

Water Quality Monitoring

Monitoring Sites

464

Active in the past 5 years

Measurements Recorded

55K

54,792 total readings

Most Measured

Physical
Microbiological
Nutrient

Categories measured most frequently

Data from the EPA Water Quality Portal (WQP), aggregating monitoring records from federal, state, and tribal sources. Each measurement represents a single sample analyzed for a specific characteristic (e.g., E. coli, pH, dissolved oxygen, nitrogen).

Live USGS Streamgage

River & Stream Conditions

Current Discharge

47.7cfs

May 14, 6:15 PM UTC

vs Long-Term Average

44%

Well below typical

Primary Streamgage

EXETER RIVER AT HAIGH ROAD, NEAR BRENTWOOD, NH

USGS site: 01073587
Drainage area: 63.5 sq mi
Long-term mean: 110 cfs

One representative streamgage (the one with the largest drainage area in the county). Many counties have multiple gauges; this view summarizes the primary one. The long-term mean is the full-record annual average; the percent-of-typical value compares the latest reading against that average.

Free tool

Estimate Your Water Costs

Water Cost Estimate

Household size

3 people · ~225 gal/day

Filter type

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Rockingham County:C — Moderate

Some violations or watershed impairment detected.

Estimates use the national average residential water rate ($0.0068/gal, EPA/AWWA 2023) and EPA WaterSense per-person consumption baseline (75 gal/person/day). Actual bills vary by utility, usage tier, and local infrastructure fees. For informational purposes only.

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Frequently Asked Questions

What is the water quality in Rockingham County, New Hampshire?

Rockingham County, New Hampshire has a drinking-water quality grade of F with a score of 26.4/100, based on EPA SDWIS compliance data. The county has 164 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and streamflow snapshots are reported separately on this page.

Are there any water violations in Rockingham County?

Rockingham County has 164 health-based drinking water violations recorded by the EPA over the past 5 years. Health-based violations indicate instances where contaminant levels exceeded EPA Maximum Contaminant Levels (MCLs). Violations may have been resolved — check with your local water utility for current status.

How healthy are the watersheds in Rockingham County?

EPA ATTAINS assessments under Clean Water Act §303(d) indicate 0.0% of Rockingham County's 1 assessed water bodies are classified as impaired (0 impaired). Impairment means the water body fails to meet state quality standards for at least one designated use — drinking water source, recreation, aquatic life, or fish consumption. Note: watershed impairment doesn't always translate to tap-water issues; treatment plants can remove most regulated contaminants.

How much water-quality monitoring happens in Rockingham County?

EPA's Water Quality Portal records 54,792 measurements from 464 monitoring sites in Rockingham County over the past five years. The most frequently measured characteristic groups are Physical, Microbiological, Nutrient. Each measurement is a single sample analyzed for one characteristic (E. coli, pH, dissolved oxygen, etc.). High monitoring density means more scientific evidence behind any reported signal — it does not by itself indicate water quality.

What's happening with rivers in Rockingham County right now?

Rockingham County's primary USGS streamgage on the EXETER RIVER has a pipeline snapshot of 47.7 cubic feet per second — 44% of the long-term mean of 109.7 cfs. This is well below typical — often a signal of drought stress on source water. For the latest gauge feed, visit waterdata.usgs.gov.

How does Rockingham County water compare to the New Hampshire average?

Rockingham County's SDWIS water quality score of 26.4/100 is lower than the New Hampshire state average of 33.2. The average water quality grade across New Hampshire is F, based on data from 10 counties with available SDWIS data.

Is tap water safe to drink in Rockingham County?

Based on EPA SDWIS data, Rockingham County has a water quality grade of F (26.4/100). This indicates below-average compliance with significant violations. Residents may want to consider home water filtration or independent testing. The grade speaks to the public water system, not the watershed — for watershed-level concerns, see the Watershed Health zone. For the most up-to-date information, contact your local water utility or review your Consumer Confidence Report (CCR).

Why does Rockingham County have so many water violations?

Rockingham County has 164 health-based drinking water violations on record from the EPA SDWIS database. A higher violation count can result from aging infrastructure, underfunded water utilities, agricultural runoff contamination, or industrial pollution. Counties with more water systems may also see more violations simply due to scale. Residents concerned about water quality should consider independent water testing and home filtration systems.

How does Rockingham County rank for water quality in New Hampshire?

Rockingham County ranks #7 out of 10 counties in New Hampshire by SDWIS water quality score (1 = best). With a score of 26.4/100, it falls in the middle third of counties statewide. The ranking reflects EPA SDWIS compliance only — not watershed impairment, monitoring density, or streamflow, which are tracked separately on this page.

Counties with Similar Water Quality

Grafton County

New Hampshire

27.4

Water score

Merrimack County

New Hampshire

20.5

Water score

Strafford County

New Hampshire

35.9

Water score

Data Sources

Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.

Watershed health and impaired-waterway data from the EPA ATTAINS Clean Water Act §303(d) assessments, state-reported and EPA-finalized.

Water-quality monitoring counts from the EPA Water Quality Portal (WQP), federated USGS, EPA, and state agency sampling records over a rolling 5-year window.

Live streamflow from the USGS National Water Information System (NWIS), continuous discharge measurements from the largest-drainage gauge in each county, compared against the full-record long-term annual mean.

Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.

By Evan Brooks, Data EditorUpdated May 14, 2026Reviewed by Evan Brooks, Data Editor

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