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Federal water data

County water report

Seminole County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Seminole County, Florida.

Water grade

C

Water score

54.3

State rank

#41

of 66

Health violations

56

EPA SDWIS, 5-year lookback

Watershed impaired

34.7%

651 water bodies assessed

Monitoring sites

443

121,922 recent measurements

Live streamflow

No gauge

ST. JOHNS RIVER NEAR SANFORD, FL

Water at a glance

Key Water Indicators for Seminole County

EPA SDWIS

Safety Grade

C

Score: 54.3 / 100

EPA SDWIS

Active Violations

56

5-year health-based lookback

EPA ATTAINS

Watershed Health

35% impaired

651 bodies assessed

USGS NWIS

Streamflow Snapshot

No gauge

ST. JOHNS RIVER NEAR SANFORD, FL

EPA WQP

Monitoring Sites

443

121,922 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

C

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

54.3/100

Health violations

56

Health-based violations

Violations per 100K served

11.0

Population-normalized SDWIS rate

Editorial analysis

Understanding Seminole County’s Water

Drinking Water Quality Overview

EPA SDWIS

Seminole County's drinking water earned a C grade, scoring 54.3 out of 100. Over the past five years, EPA SDWIS records 56 health-based violations — a pattern that public water utilities are required to disclose and correct.

Watershed Conditions

EPA ATTAINS

Under the Clean Water Act §303(d), EPA ATTAINS tracks whether waterways meet quality standards for drinking, recreation, and aquatic life (reporting cycle: 2022). A substantial 34.7% of assessed waterways are impaired (226 of 651 water bodies) across Seminole County's watersheds. The leading impairment causes are mercury in fish tissue and dissolved oxygen. Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Seminole County has extensive coverage with 443 active monitoring sites with 121,922 recent measurements on record. Predominant monitoring categories include physical and nutrient. 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 Seminole County

Water Verdict

Seminole County, Florida receives a below-average water quality assessment with a grade of C and a score of 54.3 out of 100. Residents should review their utility's Consumer Confidence Report and may want to consider additional water filtration for drinking. Separately, EPA ATTAINS assessments cover 651 water bodies in the county's watershed, with 34.7% listed as impaired under the Clean Water Act — a source-water measure that is tracked independently of tap-water compliance.

Violation Context

EPA SDWIS records for Seminole County, Florida show 56 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 11.0 violations per 100,000 people served, this rate is high and signals significant water quality management issues. This compliance record sits alongside an unusually deep monitoring archive: 121,922 water-quality results have been logged across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Tap water in Seminole County meets baseline standards but the compliance record shows room for improvement, with a Grade C rating. Seminole County's drinking-water compliance score is 54.3 out of 100. The violation rate for Seminole County is 11.0 per 100,000 people served. Residents who are immunocompromised, pregnant, or have young children may benefit from using an NSF 53-certified filter. Contacting your local utility for the current Consumer Confidence Report will confirm which specific violations were recorded and whether they have been resolved. Mercury in Fish Tissue is the leading impairment cause in Seminole County's watershed. With 443 active water-quality monitoring sites in Seminole County, data coverage is strong. Live streamflow monitoring from the ST. JOHNS RIVER gauge is also available on this page.

Regional Context

Seminole County has water quality close to the average county in Florida. Its water score is within 1.7 points of the state average, meaning its overall water system performance is broadly representative of Florida 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 Seminole County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Mercury (fish tissue)

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 2

    Low dissolved oxygen

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 3

    Phosphorus (excess nutrients)

    Impairment cause per EPA Clean Water Act §303(d) assessment

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Seminole County

EPA How's My Waterway

Interactive watershed health data for Seminole County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Seminole County

Consumer Confidence Reports (FL)

Annual water quality reports from utilities in Florida

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

34.7%

226 of 651 assessed

Moderate concern

Top Impairment Causes

  • 1

    MERCURY IN FISH TISSUE

  • 2

    DISSOLVED OXYGEN

  • 3

    PHOSPHORUS, TOTAL

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

443

Active in the past 5 years

Measurements Recorded

122K

121,922 total readings

Most Measured

  • Physical
  • Nutrient
  • Inorganics, Minor, Metals

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).

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 Seminole County:C — Moderate

Some violations or watershed impairment detected.

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 Seminole County, Florida?
Seminole County, Florida has a drinking-water quality grade of C with a score of 54.3/100, based on EPA SDWIS compliance data. The county has 56 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 Seminole County?
Seminole County has 56 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 Seminole County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 34.7% of Seminole County's 651 assessed water bodies are classified as impaired (226 impaired). The top reported causes are MERCURY IN FISH TISSUE, DISSOLVED OXYGEN, PHOSPHORUS, TOTAL. 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 Seminole County?
EPA's Water Quality Portal records 121,922 measurements from 443 monitoring sites in Seminole County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Inorganics, Minor, Metals. 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.
How does Seminole County water compare to the Florida average?
Seminole County's SDWIS water quality score of 54.3/100 is lower 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 Seminole County?
Based on EPA SDWIS data, Seminole County has a water quality grade of C (54.3/100). This indicates moderate compliance. Some violations have been recorded but overall standards are maintained. 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 Seminole County have so many water violations?
Seminole County has 56 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 Seminole County rank for water quality in Florida?
Seminole County ranks #41 out of 66 counties in Florida by SDWIS water quality score (1 = best). With a score of 54.3/100, 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

Okeechobee County

Florida

C

52.7

Water score

St. Lucie County

Florida

C

56.1

Water score

Collier County

Florida

C

56.2

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 and 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.

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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