3 community water systems serve or are based in ZIP 21771. Showing Town Of Mount Airy, the largest by reported population served. The other systems are summarized below.
- System name
- Town Of Mount Airy
- EPA PWS ID
- MD0060007
- Location
- Mount Airy, MD
- Population served
- 9,890
- Water source
- Ground water
- Primary EPA source
- EPA ECHO record for MD0060007
Make sure this is the system tied to your address before using these results to make a decision about your own water. A ZIP code is not a street address.
EPA lab monitoring (UCMR 5)
EPA UCMR 5 monitoring (Apr. 2023–Oct. 2023) detected 7 of the 30 monitored chemicals in this system's samples. Highest reported PFOA result: 12.7 ppt.
| Chemical | Highest result | EPA legal limit (MCL) | EPA health goal (MCLG) |
|---|---|---|---|
| PFOA perfluorooctanoic acid | 12.7 ppt | 4 ppt | 0 |
| PFOS perfluorooctanesulfonic acid | 6 ppt | 4 ppt | 0 |
| PFPeA perfluoropentanoic acid | 22.7 ppt | No federal MCL | — |
| PFHxA perfluorohexanoic acid | 18.4 ppt | No federal MCL | — |
| PFBA perfluorobutanoic acid | 11.6 ppt | No federal MCL | — |
| PFBS perfluorobutanesulfonic acid | 6.6 ppt | No federal MCL | — |
| PFHpA perfluoroheptanoic acid | 5.9 ppt | No federal MCL | — |
UCMR 5 results are monitoring data, not a compliance determination. PFAS compliance is governed by separate EPA drinking-water rules. Some PFAS rule changes are proposed for 2026 — see what's proposed.
Lead at customer taps
Lead at sampled customer taps, 90th percentile (Jan. 2022–Dec. 2024): 1.4 ppb. EPA's current action level is 15 ppb; its health goal (MCLG) is 0.
Lead is regulated with an action level rather than a standard MCL. EPA's lead action level is 15 ppb today; the Lead and Copper Rule Improvements lower it to 10 ppb starting Nov. 1, 2027.
Violations on the federal record
The EPA record shows 4 violations, 0 health-based.
| Type | Rule / contaminant | Since |
|---|---|---|
| Record · missed required testing or reporting | Lead & Copper Rule | 2021 |
| Record · missed required testing or reporting | — | 2022 |
| Record · missed required testing or reporting | — | 2022 |
| Record · missed required testing or reporting | Lead & Copper Rule | 2025 |
Other systems serving or based in ZIP 21771
| System | EPA PWS ID | People served | Violations |
|---|---|---|---|
| Pheasant Ridge Estates | MD0060210 | 300 | 6 |
| Mt. Airy Nursing & Rehab | MD0060211 | 104 | 10 |
On a private well? EPA public-system data does not describe your individual well. Test your water directly.
What the numbers mean
EPA uses two different benchmarks: the legal limit (MCL) and the health goal (MCLG). They are not always the same number. Read EPA's explanation →
Open the interactive report →What the government says
Sources: U.S. EPA SDWIS (system record and violations, queried live) · EPA UCMR 5 final dataset · EPA SDWIS lead & copper 90th-percentile results. EPA data can lag the latest tests.