States › Colorado › Adams County

Adams County, CO Water Quality

Water quality data for 11 public water systems serving Adams County, Colorado — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 11 water systems · 16 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

Adams County Earns a B

Adams County: 16 communities across 11 water systems. 100.0% have no open violations.

  • Median lead where detected: 2.00 ppb
  • 13 communities with a lead detection, 3 reporting none detected
  • 2 communities with PFAS above the federal limit
  • 14 with significant inspection deficiencies
  • 100.0% of communities have no open violations
2 ppb
Median Lead Level
County-wide, 90th percentile
11
Water Systems
Active CWS & NTNCWS
100%
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
  • Thornton
    2.30 ppb
    1 significant inspection deficiency
    A
  • Westminster
    1.30 ppb
    1 significant inspection deficiency
    A
  • Northglenn
    1.70 ppb
    2 significant inspection deficiencies
    A
  • Federal Heights
    1.70 ppb
    1 significant inspection deficiency
    A
  • Shaw Heights
    1.30 ppb
    1 significant inspection deficiency
    A
⚠ Needs Attention
  • Brighton
    2.00 ppb
    PFAS above the limit at 2 of 4 sampling points
    D
  • Strasburg
    1.00 ppb
    3 significant inspection deficiencies
    C
  • Todd Creek
    Not detected
    PFAS above the limit at 1 of 1 sampling points
    C
  • Commerce City
    Not detected
    3 significant inspection deficiencies
    B
  • Derby
    Not detected
    3 significant inspection deficiencies
    B
County Lead Level — Median 2 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 2 ppb — 13.3% of the federal action level
Systems by Lead Level
Under 5 ppb
8
5 – 10 ppb
5
No Data
3

All Cities in Adams County

Thornton 2.30 ppb A
Westminster 1.30 ppb A
Commerce City Not detected B
Brighton 2.00 ppb D
Northglenn 1.70 ppb A
Welby 9.00 ppb B
Derby Not detected B
Federal Heights 1.70 ppb A
Twin Lakes 9.00 ppb B
Sherrelwood 9.00 ppb B
Shaw Heights 1.30 ppb A
Berkley 9.00 ppb B
Todd Creek Not detected C
Bennett 1.00 ppb B
Strasburg 1.00 ppb C
North Washington 9.00 ppb B
Showing 16 cities
No active violations Active violations

About Adams County Drinking Water

Adams County is served by 11 water systems covering 16 communities. No community here has an open violation on record.

Of the communities reporting lead results, 13 recorded a detection, with a median of 2.00 ppb — 13% of the federal action level. 3 reported none detected, which means below the laboratory limit rather than an absence of lead.

2 of 16 communities have PFAS above the limits EPA set in 2024, measured as a running annual average at each sampling point. State inspectors recorded significant deficiencies at 14 of them.

Frequently Asked Questions

Is Adams County tap water safe to drink?▼
No community in Adams County has an open violation on record. 2 of 16 have PFAS above the federal limit, which is the main open concern.
What is the lead level in Adams County?▼
Among communities with a detection the median is 2.00 ppb, 13% of the 15 ppb action level. 3 reported none detected and 0 reported no result.
How many water systems serve Adams County?▼
11 community water systems serve 16 communities here.
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