EPA data as of Oct 2026 · page updated 2026-10-29

Home hazard report for 77378 — Willis, TX

ZIP 77378 is served by Mercy WSC: no health-based violations since 2016, latest lead result 0 ppb, PFAS not tested. Montgomery County is in EPA radon zone 3.

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Where ZIP 77378 is

Dashed: ZIP area · blue: utility service area · scroll or pinch to zoom
ZIP code areaZIP center Water utility service area PFOA/PFOS ≥ 4 ppt Lead > 15 ppb 5+ violations Superfund site (active) proposed cleaned up Circles: other water systems flagged nearby; size = people served. Tap any symbol for details.

Drinking water: Mercy WSC

EPA IDTX2040058
People served2,458
Sourcegroundwater (wells)
Connections897

Health-based violations

No health-based violations reported since 2016.

Full record for Mercy WSC →

Lead

Jan 20230 ppb
Jan 20200 ppb
Jan 20000 ppb
Jan 19970.3 ppb
Jan 19961.1 ppb
Jan 19952.7 ppb
Jan 19942.1 ppb
Jul 19931 ppb

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 Montgomery County

EPA radon zone 3 — low potential. Predicted average under 2 pCi/L — but any home can have high radon, so EPA still recommends a test.

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 Low, with relatively moderate social vulnerability and relatively low community resilience.

LightningRelatively High
TornadoRelatively High
Cold waveRelatively Moderate
HailRelatively Low
Heat waveRelatively Low
HurricaneRelatively Low
Ice stormRelatively Low
Riverine floodingRelatively Low
Strong windRelatively Low
WildfireRelatively Low
Winter weatherRelatively Low
EarthquakeVery Low
LandslideVery Low

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

No site on EPA’s Superfund National Priorities List lies within 10 miles of the center of this ZIP code.

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.

Buying a home in Willis? See the 2026 conforming, FHA and jumbo loan limits for Montgomery County →

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 77378

Who supplies drinking water to ZIP 77378?

Mercy WSC (EPA ID TX2040058), a groundwater (wells) system serving about 2,458 people.

Is there lead in Willis, TX tap water?

The utility’s latest 90th-percentile lead result (Jan 2023) 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 Willis, TX 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 77378 had violations?

No health-based violations reported since 2016.

What natural hazards affect ZIP 77378?

FEMA’s National Risk Index rates the overall natural-hazard risk here as Relatively Low; the highest-rated hazards are lightning (relatively high), tornado (relatively high), cold wave (relatively moderate).

Are there Superfund sites near 77378?

No active Superfund site within 10 miles of the ZIP center.

Is radon a problem in Montgomery County?

Montgomery County is in EPA radon zone 3 (low potential). Predicted average under 2 pCi/L — but any home can have high radon, so EPA still recommends a test.