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Federal water data

County water report

Harford County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Harford County, Maryland.

Water grade

C

Water score

60.8

State rank

#8

of 24

Health violations

10

EPA SDWIS, 5-year lookback

Watershed impaired

40.6%

96 water bodies assessed

Monitoring sites

30

48,595 recent measurements

Live streamflow

77%

SUSQUEHANNA RIVER AT CONOWINGO, MD

Water at a glance

Key Water Indicators for Harford County

EPA SDWIS

Safety Grade

C

Score: 60.8 / 100

EPA SDWIS

Active Violations

10

5-year health-based lookback

EPA ATTAINS

Watershed Health

41% impaired

96 bodies assessed

USGS NWIS

Streamflow Snapshot

77% of mean

SUSQUEHANNA RIVER AT CONOWINGO, MD

EPA WQP

Monitoring Sites

30

48,595 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

C

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

60.8/100

Health violations

10

Health-based violations

Violations per 100K served

5.9

Population-normalized SDWIS rate

Editorial analysis

Understanding Harford County’s Water

Drinking Water Quality Overview

EPA SDWIS

Harford County's drinking water earned a C grade, scoring 60.8 out of 100. Over the past five years, EPA SDWIS records 10 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). A substantial 40.6% of assessed waterways are impaired (39 of 96 water bodies) across Harford County's watersheds. The leading impairment causes are temperature and phosphorus, total. 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 2026-05-14T14:35:00.000-04:00) puts SUSQUEHANNA RIVER at 31.7k cfs — running somewhat below its historical average at 77% of mean. 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. Harford County has moderate coverage with 30 active monitoring sites with 48,595 recent measurements on record. Predominant monitoring categories include physical and nutrient. 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 Harford County

Water Verdict

Harford County receives a fair water quality assessment with a grade of C and a score of 60.8 out of 100. The water supply meets baseline federal standards, but there may be periods of elevated contaminant levels or infrastructure concerns worth monitoring.

Violation Context

Harford County has recorded 10 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 5.9 violations per 100,000 people served, this rate is moderate and suggests recurring water quality challenges.

Consumer Guidance

Tap water in Harford County meets baseline standards but the compliance record shows room for improvement, with a Grade C rating. Harford County's drinking-water compliance score is 60.8 out of 100. The violation rate for Harford County is 5.9 per 100,000 people served. Residents who are immunocompromised, pregnant, or have young children may benefit from using an NSF 53-certified filter. Contacting your local utility for the current Consumer Confidence Report will confirm which specific violations were recorded and whether they have been resolved. Temperature is the leading impairment cause in Harford County's watershed. With 30 active water-quality monitoring sites in Harford County, data coverage is strong. A pipeline streamflow snapshot from the SUSQUEHANNA RIVER gauge is also available on this page.

Regional Context

Harford County has better water quality than the average county in Maryland. Its water score is 10.3 points higher than the state average, indicating stronger water system performance relative to 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 Harford County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Elevated temperature

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 2

    Phosphorus (excess nutrients)

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 3

    Pcbs in Fish Tissue

    Impairment cause per EPA Clean Water Act §303(d) assessment

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Harford County

EPA How's My Waterway

Interactive watershed health data for Harford County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Harford County

Consumer Confidence Reports (MD)

Annual water quality reports from utilities in Maryland

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

40.6%

39 of 96 assessed

Moderate concern

Top Impairment Causes

  • 1

    TEMPERATURE

  • 2

    PHOSPHORUS, TOTAL

  • 3

    PCBS IN FISH TISSUE

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

30

Active in the past 5 years

Measurements Recorded

49K

48,595 total readings

Most Measured

  • Physical
  • Nutrient
  • Organics, Pesticide

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

31.7Kcfs

May 14, 6:35 PM UTC

vs Long-Term Average

77%

Below typical

Primary Streamgage

SUSQUEHANNA RIVER AT CONOWINGO, MD

USGS site
01578310
Drainage area
27,100 sq mi
Long-term mean
41.2K 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.

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Water Cost Estimate

3

3 people  ·  ~225 gal/day

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Harford 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 Harford County, Maryland?
Harford County, Maryland has a drinking-water quality grade of C with a score of 60.8/100, based on EPA SDWIS compliance data. The county has 10 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 Harford County?
Harford County has 10 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 Harford County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 40.6% of Harford County's 96 assessed water bodies are classified as impaired (39 impaired). The top reported causes are TEMPERATURE, PHOSPHORUS, TOTAL, PCBS IN FISH TISSUE. 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 Harford County?
EPA's Water Quality Portal records 48,595 measurements from 30 monitoring sites in Harford County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Organics, Pesticide. 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 Harford County right now?
Harford County's primary USGS streamgage on the SUSQUEHANNA RIVER has a pipeline snapshot of 31,700 cubic feet per second — 77% of the long-term mean of 41,209.65 cfs. Flow is within typical range for this gauge. For the latest gauge feed, visit waterdata.usgs.gov.
How does Harford County water compare to the Maryland average?
Harford County's SDWIS water quality score of 60.8/100 is higher than the Maryland state average of 50.5. The average water quality grade across Maryland is D, based on data from 24 counties with available SDWIS data.
Is tap water safe to drink in Harford County?
Based on EPA SDWIS data, Harford County has a water quality grade of C (60.8/100). This indicates moderate compliance. Some violations have been recorded but overall standards are maintained. 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 Harford County have so many water violations?
Harford County has 10 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 Harford County rank for water quality in Maryland?
Harford County ranks #8 out of 24 counties in Maryland by SDWIS water quality score (1 = best). With a score of 60.8/100, it falls in the top 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

Frederick County

Maryland

C

61.4

Water score

Washington County

Maryland

C

61.5

Water score

Charles County

Maryland

B

62.3

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 Reviewed by Evan Brooks, Data Editor

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