Home hazard report for 20686 — Saint Marys City, MD
ZIP 20686 is served by Saint Marys College: 1 violation since 2016, latest lead result 0 ppb, PFAS not tested. St. Mary's County is in EPA radon zone 2.
Health-based violations since 2016: Lead and Copper Rule Revisions. All are listed as resolved.
90th-percentile lead in the latest round (Jan 2021). Lead comes mostly from household plumbing and service lines, so individual homes can be higher.
This system was not part of EPA’s 2023–2025 nationwide PFAS testing (UCMR 5 covers systems serving over 3,300 people and a sample of smaller ones).
Predicted average indoor radon between 2 and 4 pCi/L. Test your home; many homes here exceed 4 pCi/L.
FEMA’s overall natural-hazard risk for this census tract, relative to the rest of the U.S.
The nearest active Superfund site is 5.8 miles away.
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Where ZIP 20686 is
Dashed: ZIP area · blue: utility service area · scroll or pinch to zoomDrinking water: Saint Marys College
Health-based violations
| Contaminant or rule | Health-based violations since 2016 |
|---|---|
| Lead and Copper Rule Revisions | 1 |
A health-based violation means a contaminant exceeded its legal limit (MCL) or a required treatment technique was not met, as reported by the state to EPA’s SDWIS. All are listed as resolved or archived; the latest began Oct 2024.
Lead
90th-percentile lead per sampling round (90% of the homes sampled were at or below this level). Black line: EPA’s 15 ppb action level; under the Lead and Copper Rule Improvements the action level becomes 10 ppb from 2027.
PFAS (“forever chemicals”)
This system was not part of EPA’s 2023–2025 nationwide PFAS testing (UCMR 5).
Radon in St. Mary's County
EPA radon zone 2 — moderate potential. Predicted average indoor radon between 2 and 4 pCi/L. Test your home; many homes here exceed 4 pCi/L.
Radon is a colorless, odorless radioactive gas from soil and rock, and the leading cause of lung cancer among non-smokers. EPA recommends fixing a home at 4 pCi/L or above and considering it from 2 pCi/L. A short-term test kit costs about $15–30. How radon zones work →
Natural hazard risk
FEMA rates the overall natural-hazard risk of this neighborhood (census tract) as Relatively Moderate, with relatively moderate social vulnerability and very high community resilience.
FEMA National Risk Index (December 2025): expected annual losses from each hazard combined with social vulnerability and community resilience, rated relative to all U.S. census tracts. Hazards not listed are not applicable here. It describes the area, not a single building; flood insurance maps (FEMA FIRMs) decide flood-insurance requirements.
Live conditions: river gauges and flood levels · tornado warnings · wildfire detections · earthquakes — our sister maps, updated from NOAA, USGS and NASA every few minutes.
Superfund sites nearby
| Site | Status | Distance |
|---|---|---|
| Patuxent River Naval Air Station St. Mary's County, Maryland · EPA ID MD7170024536 | Active (final NPL) | 5.8 mi |
EPA Superfund National Priorities List (NPL): the country’s most serious known hazardous-waste sites, each with an EPA cleanup record (linked). Distance is measured from the ZIP center to the site’s reference point; being near a site does not by itself mean exposure — EPA site pages describe what was found and how it is being cleaned up.
What this is — and isn’t. These are records your water utility and state reported to the EPA, and the EPA’s radon map for your county. They describe the system and the area, not the water from your own tap or the air in your home. For that, read your utility’s annual Consumer Confidence Report and test: lead and radon tests are inexpensive.
Questions about 20686
Who supplies drinking water to ZIP 20686?
Saint Marys College (EPA ID MD0180013), a groundwater (wells) system serving about 2,200 people.
Is there lead in Saint Marys City, MD tap water?
The utility’s latest 90th-percentile lead result (Jan 2021) was 0 ppb; EPA’s action level is 15 ppb, falling to 10 ppb from 2027. Lead mostly comes from service lines and home plumbing, so the only way to know your tap is to test it.
Does Saint Marys City, MD water have PFAS?
This system was not part of EPA’s 2023–2025 nationwide PFAS testing (UCMR 5 covers systems serving over 3,300 people and a sample of smaller ones).
Has the water system in 20686 had violations?
Health-based violations since 2016: Lead and Copper Rule Revisions. All are listed as resolved.
What natural hazards affect ZIP 20686?
FEMA’s National Risk Index rates the overall natural-hazard risk here as Relatively Moderate; the highest-rated hazards are coastal flooding (relatively high), hurricane (relatively high), lightning (relatively high).
Are there Superfund sites near 20686?
The nearest active Superfund site is 5.8 miles away. Sites within 10 miles: Patuxent River Naval Air Station (5.8 mi, Active (final NPL)).
Is radon a problem in St. Mary's County?
St. Mary's County is in EPA radon zone 2 (moderate potential). Predicted average indoor radon between 2 and 4 pCi/L. Test your home; many homes here exceed 4 pCi/L.