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Twin Falls County, ID Water Quality

Water quality data for 8 public water systems serving Twin Falls County, Idaho — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 8 water systems · 8 cities
✅
Generally Safe — Most Systems Performing Well

The majority of water systems have no active violations and lead levels well below the federal action level.

B

Twin Falls County Earns a B

Twin Falls County: 8 communities across 8 water systems. 87.5% have no open violations.

  • Median lead where detected: 2.84 ppb
  • 3 communities with a lead detection, 5 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 6 with significant inspection deficiencies
  • 87.5% of communities have no open violations
2.84 ppb
Median Lead Level
County-wide, 90th percentile
8
Water Systems
Active CWS & NTNCWS
87%
Violation-Free
No active violations on record
How we grade counties: MyWaterIQ uses EPA SDWIS enforcement data — actual MCL violations and lead test results — not the aspirational MCLG targets used by some sites. A grade reflects real compliance history, not theoretical risk. Learn more →

Cities by Water Quality

⭐ Best Performing
  • Twin Falls
    Not detected
    No federal limits exceeded on record
    B
  • Buhl
    Not detected
    2 significant inspection deficiencies
    A
  • Castleford
    Not detected
    1 significant inspection deficiency
    B
  • Filer
    2.84 ppb
    19 health-based violations since 2015
    B
  • Kimberly
    4.00 ppb
    1 significant inspection deficiency
    B
⚠ Needs Attention
  • Murtaugh
    Not detected
    1 violation currently open
    D
  • Hollister
    1.00 ppb
    3 significant inspection deficiencies
    B
  • Kimberly
    4.00 ppb
    1 significant inspection deficiency
    B
  • Hansen
    Not detected
    2 significant inspection deficiencies
    B
  • Filer
    2.84 ppb
    19 health-based violations since 2015
    B
County Lead Level — Median 2.84 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 2.84 ppb — 18.9% of the federal action level
Systems by Lead Level
Under 5 ppb
3
No Data
5

All Cities in Twin Falls County

Twin Falls Not detected B
Kimberly 4.00 ppb B
Buhl Not detected A
Filer 2.84 ppb B
Hansen Not detected B
Hollister 1.00 ppb B
Castleford Not detected B
Murtaugh Not detected D
Showing 8 cities
No active violations Active violations

About Twin Falls County Drinking Water

Twin Falls County is served by 8 water systems covering 8 communities. 88% have no open violations.

Of the communities reporting lead results, 3 recorded a detection, with a median of 2.84 ppb — 19% of the federal action level. 5 reported none detected, which means below the laboratory limit rather than an absence of lead.

No community here has PFAS above the federal limit on record. State inspectors recorded significant deficiencies at 6 of them.

Frequently Asked Questions

Is Twin Falls County tap water safe to drink?▼
88% of communities have no open violation. No community has PFAS above the federal limit on record.
What is the lead level in Twin Falls County?▼
Among communities with a detection the median is 2.84 ppb, 19% of the 15 ppb action level. 5 reported none detected and 0 reported no result.
How many water systems serve Twin Falls County?▼
8 community water systems serve 8 communities here.
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