Frederick, MD Water Quality (ZIP 21703)

Quick Answers

Is ZIP 21703 tap water safe to drink? PFAS compounds have been detected in 21703's water at an average of 10.59 ppt across 7 compounds. A certified pitcher filter or reverse osmosis system is recommended, especially for sensitive populations.

What filter should I use in 21703? Match the filter to the data: reverse osmosis handles PFAS, lead, and arsenic together; NSF-53 pitchers cover the taps you drink from. A basic Brita pitcher will not remove PFAS.

ZIP 21703 Water Quality Summary

EPA testing has detected PFAS "forever chemicals" in the water systems serving ZIP 21703 (Frederick, MD). Monitoring found a peak of 24 ppt across 2 systems, averaging 10.59 ppt over 7 detected compounds. These levels come from individual EPA UCMR 5 water samples (2023-2025). The EPA's 4 ppt limit for PFOA and PFOS is enforced on a running annual average, so a sample above it shows real exposure but is not by itself a violation.

Contamination Level: MODERATE – Moderate contamination – PFAS detected at meaningful levels; filtration recommended.

Top Detected Compounds in ZIP 21703

• PFPEA: 24 ppt (exceeds the EPA 4 ppt limit)
• PFHXA: 15.4 ppt (exceeds the EPA 4 ppt limit)
• PFOS: 15.3 ppt (exceeds the EPA 4 ppt limit)
• PFBS: 14.3 ppt
• PFBA: 10.8 ppt (exceeds the EPA 4 ppt limit)

Lead in ZIP 21703 Water

EPA Lead and Copper Rule testing recorded 9 lead samples for the systems serving 21703, with a 90th-percentile high of 0.006 mg/L (within the EPA 0.015 mg/L action level). There is no safe level of lead for children; homes built before 1986 should use a certified NSF/ANSI 53 lead filter.

EPA Violations Affecting ZIP 21703

The water systems serving 21703 have 2 health-based EPA Safe Drinking Water Act violations on record, including Lead and Copper Rule Revisions, Long Term 2 Enhanced Surface Water Treatment Rule. A health-based violation means a contaminant exceeded its federal limit or required treatment was not applied.

About the Data

These figures come from EPA UCMR5 (2023-2025) plus Lead and Copper Rule and SDWIS records for the public water system serving ZIP 21703. UCMR5 is the most comprehensive national drinking water survey in US history.

Beyond water: other exposures in Frederick, MD

Drinking water is one exposure route. These are the other federal datasets that cover ZIP 21703 and Frederick County, MD.

Radon risk in Frederick County, MD

The EPA places Frederick County, MD in Zone 1 - the EPA's highest-risk category, where the predicted average indoor radon level is above 4 pCi/L. Zone maps predict the radon potential of an area from geology and existing indoor readings - they do not describe any individual home. Radon is the leading cause of lung cancer among people who have never smoked, and the only way to know your own level is a test kit.

Lead paint risk in Frederick County, MD

Census figures show 36% of homes in Frederick County, MD were built before 1980, and 14% before 1950. Lead-based paint was banned for residential use in 1978, so older housing stock is the strongest available proxy for lead-paint exposure. This is a statistic about the county's housing, not a test of any particular property - if your home predates 1980, a lead swab test is the way to check.

Air quality in Frederick County, MD

Modelled annual fine-particle pollution (PM2.5) for Frederick County, MD averages 7.3 µg/m³, within the EPA's annual PM2.5 standard of 9 µg/m³. PM2.5 is the pollution fraction small enough to reach deep into the lungs. These are CDC modelled estimates for the county as a whole, not a reading taken at this ZIP code.

Superfund sites near 21703

There is 1 EPA Superfund (National Priorities List) site within about five miles of 21703: Fort Detrick Area B Ground Water (about 4.9 miles). Distances are measured from the ZIP code's geographic centre, so the distance from a specific address will differ. Proximity to a listed site is a fact about location - it is not itself evidence of exposure.