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Water system · PWSID ID5420058

TWIN FALLS CITY OF

TWIN FALLS, ID · ~56,121 people served

Check your exact address → TWIN FALLS overview
100
Excellent
PurityRadar safety score

PWSID

ID5420058

State

Idaho

City

TWIN FALLS

Population served

56,121

Primary source

Groundwater

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

Latest detections from EPA’s UCMR5 monitoring (through May 2025). Levels in parts per trillion (ppt).

Lithium

40,800 ppt

limit —

No federal limit

Violations & enforcement

51

Violations on record

0

Unaddressed

32

Health-based

83

Enforcement actions

From EPA ECHO (SDWIS), most recent enforcement Aug 2025. Official EPA record →

Monitoring & reporting · Nitrate began Jan 2023 Resolved
Monitoring & reporting · Lead & Copper Rule began Jul 2022 Resolved
Monitoring & reporting · Lead & Copper Rule began Jul 2022 Resolved
Monitoring & reporting · Nitrate began Jan 2022 Resolved
Monitoring & reporting · EPA contaminant 3014 began Feb 2015 Resolved
Other · EPA contaminant 7500 began Jul 2012 Resolved
Other · EPA contaminant 7500 began May 2012 Resolved
Other · EPA contaminant 7500 began May 2012 Resolved
Max contaminant level (MCL) · Arsenic health-based began Apr 2012 Resolved
Other · EPA contaminant 7500 began Mar 2012 Resolved
Other · EPA contaminant 7500 began Mar 2012 Resolved
Other · EPA contaminant 7500 began Jan 2012 Resolved

Recent enforcement actions

  • State action · SIE Aug 2025
  • State action · SIE Aug 2025
  • State action · SIA Aug 2025
  • State action · SIA Aug 2025
  • State action · SOX Dec 2024
  • State action · SOX Dec 2024
  • State action · SIE Feb 2024
  • State action · SIA Feb 2024

Area water-quality monitoring

Environmental monitoring (rivers, wells, intakes) recorded in this system’s service area in the EPA/USGS Water Quality Portal since 2018 — source/ambient water, not finished tap water. Context for the watershed, not a reading from your tap.

ContaminantMedian · max · samples

Nitrate

1 station · latest Aug 2023

2.1 · max 3.47 mg/l as N · 168

Fluoride

1 station · latest Dec 2023

0.74 · max 0.88 mg/l · 90

Arsenic

1 station · latest Dec 2023

9.2 · max 13 ug/l · 89

Atrazine

1 station · latest Jan 2024

3.13 · max 17.7 ng/l · 42

Copper

1 station · latest Aug 2020

0.91 · max 2 ug/l · 3

Lead

1 station · latest Aug 2020

0.026 · max 0.026 ug/l · 1

Source: Water Quality Portal (EPA/USGS/state agencies). Values are as-reported and aren’t health thresholds.

This profile is built from EPA public records for system ID5420058 — 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.