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Federal water data

County water report

Grayson County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Grayson County, Texas.

Water grade

F

Water score

31.4

State rank

#112

of 254

Health violations

93

EPA SDWIS, 5-year lookback

Watershed impaired

Not reported

EPA ATTAINS coverage varies by state

Monitoring sites

38

23,607 recent measurements

Live streamflow

1%

Red Rv at Denison Dam nr Denison, TX

Water at a glance

Key Water Indicators for Grayson County

EPA SDWIS

Safety Grade

F

Score: 31.4 / 100

EPA SDWIS

Active Violations

93

5-year health-based lookback

EPA ATTAINS

Watershed Health

Not reported

Coverage varies by state

USGS NWIS

Streamflow Snapshot

1% of mean

Red Rv at Denison Dam nr Denison, TX

EPA WQP

Monitoring Sites

38

23,607 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

F

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

31.4/100

Health violations

93

Health-based violations

Violations per 100K served

60.1

Population-normalized SDWIS rate

Editorial analysis

Understanding Grayson County’s Water

Drinking Water Quality Overview

EPA SDWIS

Grayson County's water systems carry a failing grade, scoring 31.4 out of 100. Over the past five years, EPA SDWIS records 93 health-based violations — a pattern that public water utilities are required to disclose and correct.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T14:00:00.000-05:00) puts Red Rv at 42.9 cfs — well below its long-term average at 1% of mean — low-flow conditions worth noting for water-dependent ecosystems. Streamflow is a leading indicator of drought stress, sediment load, and dilution capacity: low flows concentrate pollutants and warm water temperatures, stressing aquatic life and, in surface-water-dependent systems, the source water quality for treatment plants.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Grayson County has moderate coverage with 38 active monitoring sites with 23,607 recent measurements on record. Predominant monitoring categories include physical and inorganics, major, non-metals. More monitoring sites generally indicate greater scientific attention to local water conditions — and provide the baseline data that regulators use to set future impairment listings.

Editorial advisory

What the data suggests for Grayson County

Water Verdict

Grayson County receives a poor water quality assessment with a grade of F and a score of 31.4 out of 100. The water supply has documented quality issues. Residents are strongly encouraged to use filtered or bottled water for drinking and to stay informed about utility improvement plans.

Violation Context

Grayson County has recorded 93 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 60.1 violations per 100,000 people served, this rate is high and signals significant water quality management issues.

Consumer Guidance

Grayson County has a Grade F compliance record with 93 health-based violations — among the highest levels in the country. Grayson County's drinking-water compliance score is 31.4 out of 100. The violation rate for Grayson County is 60.1 per 100,000 people served. Residents are strongly advised to use a certified NSF 58 reverse-osmosis filter or bottled water for all drinking and cooking until violations are corrected. Contacting the Texas Department of Environmental Quality or Health can expedite utility compliance action. With 38 active water-quality monitoring sites in Grayson County, data coverage is strong. A pipeline streamflow snapshot from the Red Rv gauge is also available on this page.

Regional Context

Grayson County has water quality close to the average county in Texas. Its water score is within 1 points of the state average, meaning its overall water system performance is broadly representative of Texas as a whole.

Advisory text summarizes county-level public records and is not a replacement for your utility's current Consumer Confidence Report or direct local notices.

Contaminants & Resources

Key issues flagged in Grayson County's water environment

Official EPA Resources for Grayson County

EPA How's My Waterway

Interactive watershed health data for Grayson County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Grayson County

Consumer Confidence Reports (TX)

Annual water quality reports from utilities in Texas

Past 5 years

Water Quality Monitoring

Monitoring Sites

38

Active in the past 5 years

Measurements Recorded

24K

23,607 total readings

Most Measured

  • Physical
  • Inorganics, Major, Non-metals
  • Nutrient

Categories measured most frequently

Data from the EPA Water Quality Portal (WQP), aggregating monitoring records from federal, state, and tribal sources. Each measurement represents a single sample analyzed for a specific characteristic (e.g., E. coli, pH, dissolved oxygen, nitrogen).

Live USGS Streamgage

River & Stream Conditions

Current Discharge

42.9cfs

May 14, 7:00 PM UTC

vs Long-Term Average

1%

Well below typical

Primary Streamgage

Red Rv at Denison Dam nr Denison, TX

USGS site
07331600
Drainage area
39,720 sq mi
Long-term mean
4,768 cfs

One representative streamgage (the one with the largest drainage area in the county). Many counties have multiple gauges; this view summarizes the primary one. The long-term mean is the full-record annual average; the percent-of-typical value compares the latest reading against that average.

Free tool

Estimate Your Water Costs

Water Cost Estimate

3

3 people  ·  ~225 gal/day

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Grayson County:F — Failing

High violation count or severe watershed conditions.

Estimates use the national average residential water rate ($0.0068/gal, EPA/AWWA 2023) and EPA WaterSense per-person consumption baseline (75 gal/person/day). Actual bills vary by utility, usage tier, and local infrastructure fees. For informational purposes only.

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Frequently Asked Questions

What is the water quality in Grayson County, Texas?
Grayson County, Texas has a drinking-water quality grade of F with a score of 31.4/100, based on EPA SDWIS compliance data. The county has 93 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and streamflow snapshots are reported separately on this page.
Are there any water violations in Grayson County?
Grayson County has 93 health-based drinking water violations recorded by the EPA over the past 5 years. Health-based violations indicate instances where contaminant levels exceeded EPA Maximum Contaminant Levels (MCLs). Violations may have been resolved — check with your local water utility for current status.
How much water-quality monitoring happens in Grayson County?
EPA's Water Quality Portal records 23,607 measurements from 38 monitoring sites in Grayson County over the past five years. The most frequently measured characteristic groups are Physical, Inorganics, Major, Non-metals, Nutrient. Each measurement is a single sample analyzed for one characteristic (E. coli, pH, dissolved oxygen, etc.). High monitoring density means more scientific evidence behind any reported signal — it does not by itself indicate water quality.
What's happening with rivers in Grayson County right now?
Grayson County's primary USGS streamgage on the Red Rv has a pipeline snapshot of 42.9 cubic feet per second — 1% of the long-term mean of 4,767.73 cfs. This is well below typical — often a signal of drought stress on source water. For the latest gauge feed, visit waterdata.usgs.gov.
How does Grayson County water compare to the Texas average?
Grayson County's SDWIS water quality score of 31.4/100 is higher than the Texas state average of 30.4. The average water quality grade across Texas is F, based on data from 254 counties with available SDWIS data.
Is tap water safe to drink in Grayson County?
Based on EPA SDWIS data, Grayson County has a water quality grade of F (31.4/100). This indicates below-average compliance with significant violations. Residents may want to consider home water filtration or independent testing. The grade speaks to the public water system, not the watershed — for watershed-level concerns, see the Watershed Health zone. For the most up-to-date information, contact your local water utility or review your Consumer Confidence Report (CCR).
Why does Grayson County have so many water violations?
Grayson County has 93 health-based drinking water violations on record from the EPA SDWIS database. A higher violation count can result from aging infrastructure, underfunded water utilities, agricultural runoff contamination, or industrial pollution. Counties with more water systems may also see more violations simply due to scale. Residents concerned about water quality should consider independent water testing and home filtration systems.
How does Grayson County rank for water quality in Texas?
Grayson County ranks #112 out of 254 counties in Texas by SDWIS water quality score (1 = best). With a score of 31.4/100, it falls in the middle third of counties statewide. The ranking reflects EPA SDWIS compliance only — not watershed impairment, monitoring density, or streamflow, which are tracked separately on this page.

Counties with Similar Water Quality

Jeff Davis County

Texas

F

31.3

Water score

Oldham County

Texas

F

31.8

Water score

Jefferson County

Texas

F

30.8

Water score

Data Sources

Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.

Water-quality monitoring counts from the EPA Water Quality Portal (WQP), federated USGS, EPA, and state agency sampling records over a rolling 5-year window.

Live streamflow from the USGS National Water Information System (NWIS), continuous discharge measurements from the largest-drainage gauge in each county, compared against the full-record long-term annual mean.

Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

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