waterbycounty
Federal water data

County water report

Dorchester County Water Report

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

Water grade

D

Water score

47.7

State rank

#14

of 24

Health violations

4

EPA SDWIS, 5-year lookback

Watershed impaired

52.0%

75 water bodies assessed

Monitoring sites

138

136,174 recent measurements

Live streamflow

49%

CHICAMACOMICO RIVER NEAR SALEM, MD

Water at a glance

Key Water Indicators for Dorchester County

EPA SDWIS

Safety Grade

D

Score: 47.7 / 100

EPA SDWIS

Active Violations

4

5-year health-based lookback

EPA ATTAINS

Watershed Health

52% impaired

75 bodies assessed

USGS NWIS

Streamflow Snapshot

49% of mean

CHICAMACOMICO RIVER NEAR SALEM, MD

EPA WQP

Monitoring Sites

138

136,174 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

D

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

47.7/100

Health violations

4

Health-based violations

Violations per 100K served

19.8

Population-normalized SDWIS rate

Editorial analysis

Understanding Dorchester County’s Water

Drinking Water Quality Overview

EPA SDWIS

Dorchester County's drinking water received a D grade, scoring 47.7 out of 100. Over the past five years, EPA SDWIS records 4 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 52.0% of assessed waterways are impaired (39 of 75 water bodies) across Dorchester County's watersheds. The leading impairment causes are fecal coliform 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 2026-05-14T14:15:00.000-04:00) puts CHICAMACOMICO RIVER at 8.7 cfs — well below its long-term average at 49% 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. Dorchester County has extensive coverage with 138 active monitoring sites with 136,174 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 Dorchester County

Water Verdict

Dorchester County, Maryland receives a below-average water quality assessment with a grade of D and a score of 47.7 out of 100. Residents should review their utility's Consumer Confidence Report and may want to consider additional water filtration for drinking. Separately, EPA ATTAINS assessments cover 75 water bodies in the county's watershed, with 52.0% listed as impaired under the Clean Water Act — a source-water measure that is tracked independently of tap-water compliance. At the most recent USGS reading, local streamflow was below its historical mean at 48.7% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Dorchester County, Maryland show 4 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 19.8 violations per 100,000 people served, this rate is high and signals significant water quality management issues. This compliance record sits alongside an unusually deep monitoring archive: 136,174 water-quality results have been logged across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Dorchester County's drinking-water compliance is below average with a Grade D, indicating repeated or unresolved violations in the recent record. Dorchester County's drinking-water compliance score is 47.7 out of 100. The violation rate for Dorchester County is 19.8 per 100,000 people served. Residents are encouraged to use an NSF 53 or NSF 58-certified filter for drinking and cooking water until the underlying violations are resolved. Running tap water for 30 seconds before use and avoiding older lead-pipe connections can also reduce exposure risk. The current Consumer Confidence Report from your utility will specify the contaminants of concern. Fecal Coliform is the leading impairment cause in Dorchester County's watershed. With 138 active water-quality monitoring sites in Dorchester County, data coverage is strong. A pipeline streamflow snapshot from the CHICAMACOMICO RIVER gauge is also available on this page.

Regional Context

Dorchester County has water quality close to the average county in Maryland. Its water score is within 2.8 points of the state average, meaning its overall water system performance is broadly representative of Maryland as a whole.

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 Dorchester County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Fecal coliform bacteria

    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

    Nitrogen, Total

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Dorchester County

EPA How's My Waterway

Interactive watershed health data for Dorchester County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Dorchester County

Consumer Confidence Reports (MD)

Annual water quality reports from utilities in Maryland

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

52.0%

39 of 75 assessed

Moderate concern

Top Impairment Causes

  • 1

    FECAL COLIFORM

  • 2

    PHOSPHORUS, TOTAL

  • 3

    NITROGEN, TOTAL

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

138

Active in the past 5 years

Measurements Recorded

136K

136,174 total readings

Most Measured

  • Physical
  • Nutrient
  • Biological, Algae, Phytoplankton

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

8.71cfs

May 14, 6:15 PM UTC

vs Long-Term Average

49%

Well below typical

Primary Streamgage

CHICAMACOMICO RIVER NEAR SALEM, MD

USGS site
01490000
Drainage area
15 sq mi
Long-term mean
17.9 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

3

3 people  ·  ~225 gal/day

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Dorchester County:D — Poor

Elevated violations or significant watershed impairment.

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.

Try the full calculator →

Improve your water quality at home

Berkey filters remove 99.9%+ of contaminants from tap water.

Shop Berkey →

Sponsored

Test your tap water

Tap Score provides professional mail-in water testing.

Get Tested →

Frequently Asked Questions

What is the water quality in Dorchester County, Maryland?
Dorchester County, Maryland has a drinking-water quality grade of D with a score of 47.7/100, based on EPA SDWIS compliance data. The county has 4 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 Dorchester County?
Dorchester County has 4 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 Dorchester County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 52.0% of Dorchester County's 75 assessed water bodies are classified as impaired (39 impaired). The top reported causes are FECAL COLIFORM, PHOSPHORUS, TOTAL, NITROGEN, TOTAL. 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 Dorchester County?
EPA's Water Quality Portal records 136,174 measurements from 138 monitoring sites in Dorchester County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Biological, Algae, Phytoplankton. 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 Dorchester County right now?
Dorchester County's primary USGS streamgage on the CHICAMACOMICO RIVER has a pipeline snapshot of 8.71 cubic feet per second — 49% of the long-term mean of 17.88 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 Dorchester County water compare to the Maryland average?
Dorchester County's SDWIS water quality score of 47.7/100 is lower 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 Dorchester County?
Based on EPA SDWIS data, Dorchester County has a water quality grade of D (47.7/100). 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).
Does Dorchester County have clean drinking water?
Dorchester County has 4 health-based drinking water violations according to EPA records. With a water quality score of 47.7/100 and grade D, the county's drinking water has had some compliance issues but continues to be monitored. Note: drinking-water compliance speaks to the public water system, not necessarily to the watershed itself — check the Watershed Health zone for ATTAINS §303(d) data.
How does Dorchester County rank for water quality in Maryland?
Dorchester County ranks #14 out of 24 counties in Maryland by SDWIS water quality score (1 = best). With a score of 47.7/100, 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

Allegany County

Maryland

D

48.6

Water score

Worcester County

Maryland

D

46.7

Water score

Calvert County

Maryland

D

50.0

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

Explore more data for Dorchester County

Property TaxCost of LivingCrime RateIncomeHealthSchoolsDisaster RiskWeatherCounty Score