waterbycounty
Federal water data

County water report

Baltimore city Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Baltimore city, Maryland.

Water grade

A

Water score

71.8

State rank

#2

of 24

Health violations

4

EPA SDWIS, 5-year lookback

Watershed impaired

50.0%

34 water bodies assessed

Monitoring sites

12

13,758 recent measurements

Live streamflow

78%

GWYNNS FALLS AT WASHINGTON BLVD AT BALTIMORE, MD

Water at a glance

Key Water Indicators for Baltimore city

EPA SDWIS

Safety Grade

A

Score: 71.8 / 100

EPA SDWIS

Active Violations

4

5-year health-based lookback

EPA ATTAINS

Watershed Health

50% impaired

34 bodies assessed

USGS NWIS

Streamflow Snapshot

78% of mean

GWYNNS FALLS AT WASHINGTON BLVD AT BALTIMORE, MD

EPA WQP

Monitoring Sites

12

13,758 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

A

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

71.8/100

Health violations

4

Health-based violations

Violations per 100K served

0.2

Population-normalized SDWIS rate

Data center water stress

Baltimore city has 6 facilities in the DCWSI dataset.

ByCounty's DCWSI ranks this county #56 nationally by combining its water score with mapped data center density.

DCWSIThe Data Center Water Stress Index: 60% the county's water-system stress plus 40% how concentrated data centers already are, scored 0-100. Higher means data-center density and water pressure overlap more here.

73.5

0-100 index

Facility count

6

76.0 density percentile

Discharge estimate

Not reported

EPA CWA fields where available

Water vs median

+21.8

Compared with US county median

Named operators

AiNETCrown Castle FiberExpedientLumen Technologies

Mapped facilities

  • AiNET One Market Center

    Baltimore · AiNET

    OSM

  • Baltimore Technology Park

    Baltimore

    OSM

  • Crown Castle Baltimore

    Baltimore · Crown Castle Fiber

    OSM

  • Expedient Tidepoint

    Expedient

    OSM

  • Johns Hopkins Data Center

    Facility details limited

    OSM

  • Lumen Baltimore

    Lumen Technologies

    OSM
See the Baltimore city data-center reportReview methodology

Data Center Water Budget Calculator

Estimate daily water use for a hypothetical facility in Baltimore city.

1 MW1,000 MW
40%100%
799K gallons/dayHigh Impact

Your facility would use 56.0% of this county's industrial water baseline. Verify water rights and long-term drought projections before committing.

56.0% of county industrial baseline0.63 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 Baltimore city’s Water

Drinking Water Quality Overview

EPA SDWIS

Baltimore city earns an A grade for drinking water quality, scoring 71.8 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 50.0% of assessed waterways are impaired (17 of 34 water bodies) across Baltimore city's watersheds. The leading impairment causes are total suspended solids (tss) and habitat alterations. 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 2026-05-14T14:20:00.000-04:00) puts GWYNNS FALLS at 75.9 cfs — running somewhat below its historical average at 78% 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. Baltimore city has moderate coverage with 12 active monitoring sites with 13,758 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 Baltimore city

Water Verdict

Baltimore city, Maryland receives a good water quality assessment with a grade of A and a score of 71.8 out of 100. While the water supply is generally safe, occasional monitoring gaps or minor contaminant detections may occur. Separately, EPA ATTAINS assessments cover 34 water bodies in the county's watershed, with 50.0% 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 78.4% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Baltimore city, Maryland show 4 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 0.2 violations per 100,000 people served, this rate is relatively low compared to many U.S. counties. This compliance record sits alongside an unusually deep monitoring archive: 13,758 water-quality results have been logged across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Tap water compliance data for Baltimore city shows a A grade. Baltimore city's drinking-water compliance score is 71.8 out of 100. Reviewing your utility's most recent Consumer Confidence Report provides the most accurate picture of detected contaminants and treatment status. An NSF-certified water filter can add an extra layer of safety for any household concerns. Total Suspended Solids (Tss) is the leading impairment cause in Baltimore city's watershed. A pipeline streamflow snapshot from the GWYNNS FALLS gauge is also available on this page.

Regional Context

Baltimore city has better water quality than the average county in Maryland. Its water score is 21.3 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 Baltimore city's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Total Suspended Solids (Tss)

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

  • 2

    Habitat Alterations

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

  • 3

    Chloride

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Baltimore city

EPA How's My Waterway

Interactive watershed health data for Baltimore city

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Baltimore city

Consumer Confidence Reports (MD)

Annual water quality reports from utilities in Maryland

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

50.0%

17 of 34 assessed

Moderate concern

Top Impairment Causes

  • 1

    TOTAL SUSPENDED SOLIDS (TSS)

  • 2

    HABITAT ALTERATIONS

  • 3

    CHLORIDE

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

12

Active in the past 5 years

Measurements Recorded

14K

13,758 total readings

Most Measured

  • Physical
  • Microbiological
  • Not Assigned

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

75.9cfs

May 14, 6:20 PM UTC

vs Long-Term Average

78%

Below typical

Primary Streamgage

GWYNNS FALLS AT WASHINGTON BLVD AT BALTIMORE, MD

USGS site
01589352
Drainage area
65.9 sq mi
Long-term mean
96.8 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 Baltimore city: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 Baltimore city, Maryland?
Baltimore city, Maryland has a drinking-water quality grade of A with a score of 71.8/100, 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 Baltimore city?
Baltimore city 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 Baltimore city?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 50.0% of Baltimore city's 34 assessed water bodies are classified as impaired (17 impaired). The top reported causes are TOTAL SUSPENDED SOLIDS (TSS), HABITAT ALTERATIONS, CHLORIDE. 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 Baltimore city?
EPA's Water Quality Portal records 13,758 measurements from 12 monitoring sites in Baltimore city over the past five years. The most frequently measured characteristic groups are Physical, Microbiological, Not Assigned. 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 Baltimore city right now?
Baltimore city's primary USGS streamgage on the GWYNNS FALLS has a pipeline snapshot of 75.9 cubic feet per second — 78% of the long-term mean of 96.81 cfs. Flow is within typical range for this gauge. For the latest gauge feed, visit waterdata.usgs.gov.
How does Baltimore city water compare to the Maryland average?
Baltimore city's SDWIS water quality score of 71.8/100 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 Baltimore city?
Based on EPA SDWIS data, Baltimore city has a water quality grade of A (71.8/100). This indicates good to excellent water quality with strong SDWIS compliance. 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 Baltimore city have clean drinking water?
Baltimore city has 4 health-based drinking water violations according to EPA records. With a water quality score of 71.8/100 and grade A, 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 Baltimore city rank for water quality in Maryland?
Baltimore city ranks #2 out of 24 counties in Maryland by SDWIS water quality score (1 = best). With a score of 71.8/100, 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

Howard County

Maryland

A

70.6

Water score

Anne Arundel County

Maryland

B

67.5

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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