Frederick, MD Water Quality (ZIP 21704)

Quick Answers

Is ZIP 21704 tap water safe to drink? No PFAS above thresholds is reported for 21704 in current EPA data. Lead risk from older plumbing is a separate question; the results below cover the regulated contaminants tested for this system.

What filter should I use in 21704? A reverse osmosis system (NSF/ANSI 58) removes 90%+ of PFAS, lead, and arsenic. For smaller households, an NSF-53 certified pitcher (Clearly Filtered, ZeroWater) works. Standard Brita cartridges are not certified for PFAS.

ZIP 21704 Water Quality Summary

The public water system serving ZIP 21704 (Frederick, MD) is not currently reported as having detected PFAS in recent EPA UCMR5 testing, though other regulated contaminants appear in the data below.

Contamination Level: NONE – No PFAS detected in recent testing for the systems serving this ZIP code.

Lead in ZIP 21704 Water

EPA Lead and Copper Rule testing recorded 21 lead samples for the systems serving 21704, with a 90th-percentile high of 0.0173 mg/L (above 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 21704

The water systems serving 21704 have 3 health-based EPA Safe Drinking Water Act violations on record, including Total Trihalomethanes. A health-based violation means a contaminant exceeded its federal limit or required treatment was not applied.

About the Data

Source: EPA UCMR5 monitoring (2023-2025), Lead and Copper Rule samples, and SDWIS violation records tied to the water system that serves 21704 in Frederick, MD.

Beyond water: other exposures in Frederick, MD

Drinking water is one exposure route. These are the other federal datasets that cover ZIP 21704 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.