ANDESITE RIDGE WATER SYSTEM

BIG SKY, MT · ~450 people served

Check your exact address → BIG SKY overview

100

Excellent

PurityRadar safety score

PWSID

MT0004468

State

Montana

City

BIG SKY

Population served

450

Primary source

GWP

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 Jul 2020. Official EPA record →

Other · EPA contaminant 7000 began Jul 2020 Resolved

Max contaminant level (MCL) · Total coliform health-based began Feb 2015 Resolved

Treatment technique · Lead & Copper Rule health-based began Jul 2012 Resolved

Other · EPA contaminant 0700 began Nov 2010 Resolved

Max contaminant level (MCL) · Total coliform health-based began Nov 2010 Resolved

Monitoring & reporting · Total coliform began Feb 2010 Resolved

Monitoring & reporting · Lead & Copper Rule began Jan 2009 Resolved

Max contaminant level (MCL) · Total coliform health-based began Jul 2007 Resolved

Monitoring & reporting · Total coliform began Jan 2007 Resolved

Monitoring & reporting · Total coliform began Apr 2006 Resolved

Recent enforcement actions

State action · SOX Jul 2020
State action · SIA Jul 2020
State action · SOX Mar 2015
State action · SIA Feb 2015
State action · SIE Feb 2015
State action · SIA Feb 2015
State action · SIE Nov 2012
State action · SIA Nov 2012

This profile is built from EPA public records for system MT0004468 — 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.