waterbycounty
EPA SDWIS

Duval County Water Quality

Duval County, Florida

Water Grade

A

Water Score

71.8

Violations

2

State Rank

#12

of 66 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

A

Based on EPA compliance history and violation data

Water Score

71.8/100

Higher = better quality

Health Violations

2

Health-based violations

Violation Rate

0.2%

Systems with violations

Water Advisory: Duval County

Water Verdict

Duval County receives a good water quality assessment with a grade of A and a score of 71.8 out of 100. While the water supply is generally safe, occasional monitoring gaps or minor contaminant detections may occur.

Violation Context

Duval County has recorded 2 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 0.2 violations per 1,000 residents, this rate is relatively low compared to many U.S. counties.

Consumer Guidance

Tap water in Duval County is generally safe to drink based on available data. Residents should still review their utility's annual Consumer Confidence Report for transparency on detected contaminants. With 2 recorded health violations, staying informed about utility communications and boil-water notices is especially important. For long-term peace of mind, request your utility's latest Consumer Confidence Report and consider independent water testing if you have specific health concerns.

Regional Context

Duval County has better water quality than the average county in Florida. Its water score is 15.8 points higher than the state average, indicating stronger water system performance relative to neighboring counties.

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

29.9%

259 of 865 assessed

Some impairment

Top Impairment Causes

  • 1

    MERCURY IN FISH TISSUE

  • 2

    IRON

  • 3

    DISSOLVED OXYGEN

Source: EPA ATTAINS · Reporting cycle 2022

Impairment is determined under the Clean Water Act §303(d): a water body is impaired when it fails to meet state-defined quality standards for designated uses (drinking, recreation, aquatic life). Assessment coverage varies by state — counties without assessed water bodies are not shown.

Past 5 years

Water Quality Monitoring

Monitoring Sites

406

Active in the past 5 years

Measurements Recorded

120K

119,762 total readings

Most Measured

  • Physical
  • Inorganics, Minor, 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

153.0Kcfs

May 14, 6:30 PM UTC

vs Long-Term Average

2892%

Well above typical

Primary Streamgage

ST. JOHNS RIVER AT JACKSONVILLE, FL

USGS site
02246500
Drainage area
8,850 sq mi
Long-term mean
5,291 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; "% of typical" compares the latest reading against that average.

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Frequently Asked Questions

What is the water quality in Duval County, Florida?
Duval County, Florida has a drinking-water quality grade of A with a score of 71.8/100, based on EPA SDWIS compliance data. The county has 2 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and live streamflow are reported separately on this page.
Are there any water violations in Duval County?
Duval County has 2 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 healthy are the watersheds in Duval County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 29.9% of Duval County's 865 assessed water bodies are classified as impaired (259 impaired). The top reported causes are MERCURY IN FISH TISSUE, IRON, DISSOLVED OXYGEN. Impairment means the water body fails to meet state quality standards for at least one designated use — drinking water source, recreation, aquatic life, or fish consumption. Note: watershed impairment doesn't always translate to tap-water issues; treatment plants can remove most regulated contaminants.
How much water-quality monitoring happens in Duval County?
EPA's Water Quality Portal records 119,762 measurements from 406 monitoring sites in Duval County over the past five years. The most frequently measured characteristic groups are Physical, Inorganics, Minor, 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 Duval County right now?
Duval County's primary USGS streamgage on the ST. JOHNS RIVER is currently reading 153,000 cubic feet per second — 2892% of the long-term mean of 5,290.71 cfs. This is well above typical — often a signal of recent precipitation or storm runoff. For genuine real-time data, visit waterdata.usgs.gov.
How does Duval County water compare to the Florida average?
Duval County's SDWIS water quality score of 71.8/100 is higher than the Florida state average of 56.0. The average water quality grade across Florida is D, based on data from 66 counties with available SDWIS data.
Is tap water safe to drink in Duval County?
Based on EPA SDWIS data, Duval County has a water quality grade of A (71.8/100). This indicates good to excellent water quality with strong SDWIS compliance. 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).
Does Duval County have clean drinking water?
Duval County has 2 health-based drinking water violations according to EPA records. With a water quality score of 71.8/100 and grade A, the county's drinking water has had some compliance issues but continues to be monitored. Note: drinking-water compliance speaks to the public water system, not necessarily to the watershed itself — check the Watershed Health zone for ATTAINS §303(d) data.
How does Duval County rank for water quality in Florida?
Duval County ranks #12 out of 66 counties in Florida by SDWIS water quality score (1 = best). With a score of 71.8/100, it falls in the top 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

Okaloosa County

Florida

A

71.3

Water score

Clay County

Florida

A

71.1

Water score

Hernando County

Florida

A

70.8

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.

Watershed health and impaired-waterway data from the EPA ATTAINS Clean Water Act §303(d) assessments — state-reported, EPA-finalized.

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 Logan Johnson, Founder & Data EditorUpdated Reviewed by Logan Johnson, Founder & Data Editor

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