Water quality · ZIP 21201
Water quality in Baltimore, MD
ZIP 21201 is in Baltimore (city), Maryland. The largest community water system EPA lists there, CITY OF BALTIMORE (serving about 1,600,000 people), reported 1 health-based violation in the last 3 years. This is the utility's federal record, not a test of the water at any address.
Baltimore (city), Maryland · EPA SDWIS
CITY OF BALTIMORE
PWSID MD0300002 · population served 1,600,000 · surface water
- Health-based violations (3y)
- 1
- Total violations (3y)
- 2
- Most recent
- 2026-01-01 — MCL (health-based)
This is federal SDWIS reporting data for the community water system serving this county, not an address-level test result. Private well water is never covered by SDWIS. Where a county is served by multiple systems, this shows the one serving the most people.
Next step for your own home
What this page shows
The community water system serving this ZIP's county, its EPA SDWIS record, and any health-based violations in the last 3 years — shown above.
Source & refresh
EPA SDWIS. States report water-system records to EPA every quarter. The violation counts here cover the last 3 years. Primary source →
Limitations specific to this source
Where a county has several water systems, zipradar shows the one serving the most people and says how many others are on record; yours may be a different one. Private well water is not covered.
Maryland context
Chesapeake flood, lead pipes
Maryland has dense FEMA NFHL coverage along Chesapeake Bay tributaries. Baltimore City has extensive LCRR lead-service-line obligations and flagged EPA SDWIS compliance history. Radon Zone 1-2 across most counties.
See Maryland state page for the full state-level rollup across all 12 dimensions.
Read more on water quality
Editorial deep-dives explaining the source data, its limits, and how to read it.
Flood zones explained — what AE, X, and VE actually mean
Plain-English guide to FEMA flood-zone codes (A, AE, AH, V, VE, X, X-shaded). What the 1% and 0.2% annual-chance zones mean for your property and your insurance.
EPA Radon Zones — what 1, 2, and 3 mean and when you should test
EPA classifies every US county into Zone 1 (high), Zone 2 (moderate), or Zone 3 (low) for radon. Plain-English guide to the classifications and at-home testing.
EPA AQI categories explained — what 0–50 Good through 301–500 Hazardous mean
Plain-English guide to the six EPA Air Quality Index categories: 0–50 Good, 51–100 Moderate, 101–150 Unhealthy for Sensitive Groups, 151–200 Unhealthy, 201–300 Very Unhealthy, 301–500 Hazardous — what each level means and who is at risk.
Lead and Copper Rule 2024 — the federal lead-pipe inventory mandate
The 2024 Lead and Copper Rule Revisions (LCRR) require every US community water system to inventory and report lead service lines. Plain-English guide.
The other dimensions for ZIP 21201
Water quality is one of twelve public-records dimensions zipradar indexes per address. See the ZIP 21201 index for the other eleven — each with its own regulator, source and link:
All dimensions for Baltimore, MD →Frequently asked questions
What is the water quality for ZIP 21201?
Baltimore (city), Maryland (which covers ZIP 21201) is served by CITY OF BALTIMORE (EPA PWSID MD0300002), a community water system serving a reported population of 1,600,000. Health-based violations in the last 3 years: 1. This is federal SDWIS reporting data for the community water system serving this county, not an address-level test result. Private well water is never covered by SDWIS. Where a county is served by multiple systems, this shows the one serving the most people.
Where does the water quality data come from?
Source: EPA SDWIS. States report water-system records to EPA every quarter. The violation counts here cover the last 3 years. The original is at https://www.epa.gov/ground-water-and-drinking-water/safe-drinking-water-information-system-sdwis-federal-reporting.
What are the limitations of water quality data?
Where a county has several water systems, zipradar shows the one serving the most people and says how many others are on record; yours may be a different one. Private well water is not covered.
Is ZIP 21201 (Baltimore) data current?
zipradar last checked this page against the source on 2026-09-24. States report water-system records to EPA every quarter. The violation counts here cover the last 3 years. The ZIP 21201 overview at /zip/21201/ lists the other topics zipradar covers for this ZIP.