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

Home hazard report for 74856 — Mill Creek, OK

ZIP 74856 is served by Johnston Co RWD #3: 1 violation since 2016, latest lead result 1.4 ppb, PFAS not tested. Johnston County is in EPA radon zone 3.

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Where ZIP 74856 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: Johnston Co RWD #3

EPA IDOK2003511
People served2,783
Sourcegroundwater (wells)
Connections1,298

Health-based violations

Contaminant or ruleHealth-based violations since 2016
Lead and Copper Rule Revisions1

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.

Full record for Johnston Co RWD #3 →

Lead

Jan 20221.4 ppb
Jan 20190 ppb
Jan 20160 ppb
Jan 20130 ppb
Jan 20120 ppb
Jan 20115.3 ppb
Jul 20105.8 ppb
Jan 20100 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 Johnston 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 Moderate, with very high social vulnerability and relatively low community resilience.

DroughtRelatively High
HailRelatively High
Heat waveRelatively High
Ice stormRelatively High
Strong windRelatively High
TornadoRelatively High
Cold waveRelatively Moderate
LightningRelatively Moderate
WildfireRelatively Moderate
Winter weatherRelatively Moderate
LandslideRelatively Low
Riverine floodingRelatively Low
EarthquakeVery Low
HurricaneVery 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 Mill Creek? See the 2026 conforming, FHA and jumbo loan limits for Johnston 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 74856

Who supplies drinking water to ZIP 74856?

Johnston Co RWD #3 (EPA ID OK2003511), a groundwater (wells) system serving about 2,783 people.

Is there lead in Mill Creek, OK tap water?

The utility’s latest 90th-percentile lead result (Jan 2022) was 1.4 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 Mill Creek, OK 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 74856 had violations?

Health-based violations since 2016: Lead and Copper Rule Revisions. All are listed as resolved.

What natural hazards affect ZIP 74856?

FEMA’s National Risk Index rates the overall natural-hazard risk here as Relatively Moderate; the highest-rated hazards are drought (relatively high), hail (relatively high), heat wave (relatively high).

Are there Superfund sites near 74856?

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

Is radon a problem in Johnston County?

Johnston 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.