waterbycounty
EPA SDWIS

Miami-Dade County Water Quality

Miami-Dade County, Florida

Water Grade

A

Water Score

70.4

Violations

25

State Rank

#18

of 66 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

A

Based on EPA compliance history and violation data

Water Score

70.4/100

Higher = better quality

Health Violations

25

Health-based violations

Violation Rate

0.8%

Systems with violations

Water Advisory: Miami-Dade County

Water Verdict

Miami-Dade County receives a good water quality assessment with a grade of A and a score of 70.4 out of 100. While the water supply is generally safe, occasional monitoring gaps or minor contaminant detections may occur.

Violation Context

Miami-Dade County has recorded 25 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 0.8 violations per 1,000 residents, this rate is relatively low compared to many U.S. counties.

Consumer Guidance

Tap water in Miami-Dade 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 25 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

Miami-Dade County has better water quality than the average county in Florida. Its water score is 14.4 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

60.1%

304 of 506 assessed

High concern

Top Impairment Causes

  • 1

    MERCURY IN FISH TISSUE

  • 2

    DISSOLVED OXYGEN

  • 3

    CHLOROPHYLL-A

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

485

Active in the past 5 years

Measurements Recorded

298K

298,206 total readings

Most Measured

  • Physical
  • Nutrient
  • Organics, Pesticide

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

1.84cfs

May 14, 6:45 PM UTC

vs Long-Term Average

2%

Well below typical

Primary Streamgage

N.W. WELLFIELD CANAL NR DADE BROWARD LEVEE NR PENN

USGS site
02287497
Long-term mean
78.9 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 Miami-Dade County, Florida?
Miami-Dade County, Florida has a drinking-water quality grade of A with a score of 70.4/100, based on EPA SDWIS compliance data. The county has 25 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 Miami-Dade County?
Miami-Dade County has 25 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 Miami-Dade County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 60.1% of Miami-Dade County's 506 assessed water bodies are classified as impaired (304 impaired). The top reported causes are MERCURY IN FISH TISSUE, DISSOLVED OXYGEN, CHLOROPHYLL-A. 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 Miami-Dade County?
EPA's Water Quality Portal records 298,206 measurements from 485 monitoring sites in Miami-Dade County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Organics, Pesticide. 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 Miami-Dade County right now?
Miami-Dade County's primary USGS streamgage on the N.W. WELLFIELD CANAL is currently reading 1.84 cubic feet per second — 2% of the long-term mean of 78.89 cfs. This is well below typical — often a signal of drought stress on source water. For genuine real-time data, visit waterdata.usgs.gov.
How does Miami-Dade County water compare to the Florida average?
Miami-Dade County's SDWIS water quality score of 70.4/100 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 Miami-Dade County?
Based on EPA SDWIS data, Miami-Dade County has a water quality grade of A (70.4/100). 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).
Why does Miami-Dade County have so many water violations?
Miami-Dade County has 25 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 Miami-Dade County rank for water quality in Florida?
Miami-Dade County ranks #18 out of 66 counties in Florida by SDWIS water quality score (1 = best). With a score of 70.4/100, 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

Walton County

Florida

A

70.4

Water score

Broward County

Florida

A

70.6

Water score

Manatee County

Florida

A

70.6

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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