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EPA SDWIS

Seminole County Water Quality

Seminole County, Florida

Water Grade

C

Water Score

54.3

Violations

56

State Rank

#41

of 66 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

C

Based on EPA compliance history and violation data

Water Score

54.3/100

Higher = better quality

Health Violations

56

Health-based violations

Violation Rate

11.0%

Systems with violations

Water Advisory: Seminole County

Water Verdict

Seminole County 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.

Violation Context

Seminole County has recorded 56 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 11.0 violations per 1,000 residents, this rate is high and signals significant water quality management issues.

Consumer Guidance

Tap water in Seminole County meets baseline standards, but residents who are immunocompromised or have young children may want to use an NSF-certified water filter as a precaution. With 56 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

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.

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).

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

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