YNP-MAMMOTH HOT SPRINGS

YELLOWSTONE NATIONAL PARK, WY · ~2,600 people served

Check your exact address → YELLOWSTONE NATIONAL PARK overview

100

Excellent

PurityRadar safety score

PWSID

WY5680092

State

Wyoming

City

YELLOWSTONE NATIONAL PARK

Population served

2,600

Primary source

Surface water

Score history

No change since tracking began Jun 18, 2026.

Jun 18, 2026 · score 100 Jun 18, 2026 · score 100

2 score updates logged since tracking began Jun 18, 2026. Each future EPA re-score adds a point.

PFAS & contaminant readings

No PFAS detections are on record for this system from EPA’s UCMR5 monitoring (2023–25). Absence of a detection isn’t a guarantee — not every system was sampled, and this dataset doesn’t cover other contaminants.

Violations & enforcement

Violations on record

Unaddressed

Health-based

Enforcement actions

From EPA ECHO (SDWIS), most recent enforcement Nov 2023. Official EPA record →

Monitoring & reporting · EPA contaminant 0200 began Aug 2023 Resolved

Monitoring & reporting · Total trihalomethanes (TTHM) began Jun 2017 Resolved

Monitoring & reporting · Haloacetic acids (HAA5) began Jun 2017 Resolved

Monitoring & reporting · Total coliform began Sep 2013 Resolved

Treatment technique · EPA contaminant 0200 health-based began Jul 2005 Resolved

Monitoring & reporting · Bromate began Jan 2005 Resolved

Recent enforcement actions

State action · SOX Nov 2023
State action · SIA Oct 2023
State action · SOX Mar 2019
State action · SIF Jun 2014
State action · SOX Oct 2013
State action · SOX Jul 2007
State action · SIA Dec 2005
State action · SIE May 2005

This profile is built from EPA public records for system WY5680092 — SDWIS violations and UCMR5 PFAS sampling. The score is system-level and can’t account for your home’s plumbing (older pipes can add lead at the tap). For health decisions, check your exact address, read the utility’s Consumer Confidence Report, and confirm with your provider.