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Grayson County, TX Water Quality

Water quality data for 18 public water systems serving Grayson County, Texas — based on EPA SDWIS enforcement records, lead testing results, and health-based violation history.

📅 2026 Report 🔄 Data updated 2026 Q2 📍 18 water systems · 18 cities
✅
Excellent — All Systems Performing Well

Water quality across the county is outstanding with minimal violations and very low lead levels.

A

Grayson County Earns a A

Grayson County: 18 communities across 18 water systems. 88.9% have no open violations.

  • Median lead where detected: 1.51 ppb
  • 8 communities with a lead detection, 10 reporting none detected
  • 0 communities with PFAS above the federal limit
  • 0 with significant inspection deficiencies
  • 88.9% of communities have no open violations
1.51 ppb
Median Lead Level
County-wide, 90th percentile
18
Water Systems
Active CWS & NTNCWS
88%
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
  • Sherman
    Not detected
    No federal limits exceeded on record
    A
  • Denison
    1.82 ppb
    No federal limits exceeded on record
    A
  • Van Alstyne
    0.81 ppb
    No federal limits exceeded on record
    A
  • Whitesboro
    Not detected
    No federal limits exceeded on record
    A
  • Howe
    3.47 ppb
    No federal limits exceeded on record
    B
⚠ Needs Attention
  • Whitewright
    Not detected
    1 violation currently open
    C
  • Bells
    1.11 ppb
    1 violation currently open
    C
  • Preston
    3.33 ppb
    37 health-based violations since 2015
    B
  • Sherman
    Not detected
    No federal limits exceeded on record
    A
  • Denison
    1.82 ppb
    No federal limits exceeded on record
    A
County Lead Level — Median 1.51 ppb
Based on most recent 90th percentile lead tests across all reporting systems
0 ppb5 ppb10 ppb15 ppb
County median: 1.51 ppb — 10.1% of the federal action level
Systems by Lead Level
Under 5 ppb
8
No Data
10

All Cities in Grayson County

Sherman Not detected A
Denison 1.82 ppb A
Van Alstyne 0.81 ppb A
Whitesboro Not detected A
Howe 3.47 ppb B
Pottsboro 3.80 ppb B
Gunter 1.20 ppb B
Collinsville Not detected B
Whitewright Not detected C
Bells 1.11 ppb C
Tioga Not detected B
Preston 3.33 ppb B
Tom Bean Not detected B
Sherwood Shores Not detected B
Knollwood Not detected B
Southmayd Not detected B
Sadler 1.15 ppb B
Dorchester Not detected B
Showing 18 cities
No active violations Active violations

About Grayson County Drinking Water

Grayson County is served by 18 water systems covering 18 communities. 89% have no open violations.

Of the communities reporting lead results, 8 recorded a detection, with a median of 1.51 ppb — 10% of the federal action level. 10 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 no significant deficiencies.

Frequently Asked Questions

Is Grayson County tap water safe to drink?▼
89% of communities have no open violation. No community has PFAS above the federal limit on record.
What is the lead level in Grayson County?▼
Among communities with a detection the median is 1.51 ppb, 10% of the 15 ppb action level. 10 reported none detected and 0 reported no result.
How many water systems serve Grayson County?▼
18 community water systems serve 18 communities here.
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