waterbycounty
EPA SDWIS

Seneca County Water Quality

Seneca County, New York

Water Grade

F

Water Score

28.8

Violations

18

State Rank

#41

of 57 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

F

Based on EPA compliance history and violation data

Water Score

28.8/100

Higher = better quality

Health Violations

18

Health-based violations

Violation Rate

72.5%

Systems with violations

Water Advisory: Seneca County

Water Verdict

Seneca County receives a poor water quality assessment with a grade of F and a score of 28.8 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

Seneca County has recorded 18 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 72.5 violations per 1,000 residents, this rate is high and signals significant water quality management issues.

Consumer Guidance

Residents of Seneca County are advised to use filtered or bottled water for drinking and cooking until water quality improves. A reverse-osmosis or activated-carbon filter certified to remove the contaminants listed in the utility's Consumer Confidence Report is recommended. With 18 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

Seneca County has poorer water quality than the average county in New York. Its water score is 11.3 points lower than the state average, suggesting more challenges with contamination control or infrastructure than neighboring counties.

Past 5 years

Water Quality Monitoring

Monitoring Sites

7

Active in the past 5 years

Measurements Recorded

3.1K

3,100 total readings

Most Measured

  • Nutrient
  • Cyanotoxins, Phytotoxins
  • Organics, Other

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

4,550cfs

May 14, 6:45 PM UTC

vs Long-Term Average

287%

Well above typical

Primary Streamgage

SENECA RIVER AT FREE BRIDGE CORNERS NY

USGS site
0423406130
Drainage area
1,566 sq mi
Long-term mean
1,583 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 Seneca County, New York?
Seneca County, New York has a drinking-water quality grade of F with a score of 28.8/100, based on EPA SDWIS compliance data. The county has 18 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 Seneca County?
Seneca County has 18 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 Seneca County?
EPA's Water Quality Portal records 3,100 measurements from 7 monitoring sites in Seneca County over the past five years. The most frequently measured characteristic groups are Nutrient, Cyanotoxins, Phytotoxins, Organics, Other. 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 Seneca County right now?
Seneca County's primary USGS streamgage on the SENECA RIVER is currently reading 4,550 cubic feet per second — 287% of the long-term mean of 1,583.18 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 Seneca County water compare to the New York average?
Seneca County's SDWIS water quality score of 28.8/100 is lower than the New York state average of 40.1. The average water quality grade across New York is D, based on data from 57 counties with available SDWIS data.
Is tap water safe to drink in Seneca County?
Based on EPA SDWIS data, Seneca County has a water quality grade of F (28.8/100). 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 Seneca County have so many water violations?
Seneca County has 18 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 Seneca County rank for water quality in New York?
Seneca County ranks #41 out of 57 counties in New York by SDWIS water quality score (1 = best). With a score of 28.8/100, it falls in the bottom 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

Ontario County

New York

F

29.0

Water score

Steuben County

New York

F

28.0

Water score

Delaware County

New York

F

30.9

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

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