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Federal water data

County water report

Yankton County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Yankton County, South Dakota.

Water grade

F

Water score

41.3

State rank

#40

of 63

Health violations

5

EPA SDWIS, 5-year lookback

Watershed impaired

Not reported

EPA ATTAINS coverage varies by state

Monitoring sites

10

428 recent measurements

Live streamflow

No gauge

MISSOURI RIVER AT YANKTON, SD

Water at a glance

Key Water Indicators for Yankton County

EPA SDWIS

Safety Grade

F

Score: 41.3 / 100

EPA SDWIS

Active Violations

5

5-year health-based lookback

EPA ATTAINS

Watershed Health

Not reported

Coverage varies by state

USGS NWIS

Streamflow Snapshot

No gauge

MISSOURI RIVER AT YANKTON, SD

EPA WQP

Monitoring Sites

10

428 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

F

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

41.3/100

Health violations

5

Health-based violations

Violations per 100K served

30.1

Population-normalized SDWIS rate

Editorial analysis

Understanding Yankton County’s Water

Drinking Water Quality Overview

EPA SDWIS

Yankton County's water systems carry a failing grade, scoring 41.3 out of 100. Over the past five years, EPA SDWIS records 5 health-based violations — a pattern that public water utilities are required to disclose and correct.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Yankton County has moderate coverage with 10 active monitoring sites with 428 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 Yankton County

Water Verdict

Yankton County receives a below-average water quality assessment with a grade of F and a score of 41.3 out of 100. Residents should review their utility's Consumer Confidence Report and may want to consider additional water filtration for drinking.

Violation Context

Yankton County has recorded 5 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 30.1 violations per 100,000 people served, this rate is high and signals significant water quality management issues.

Consumer Guidance

Drinking-water compliance in Yankton County is rated Grade F, reflecting significant health-based violations in the recent reporting period. Yankton County's drinking-water compliance score is 41.3 out of 100. The violation rate for Yankton County is 30.1 per 100,000 people served. An NSF 53 or NSF 58-certified filter is recommended for drinking and cooking water. Check the Consumer Confidence Report from your utility to identify the specific contaminants and required corrective actions — utilities are legally required to notify customers of violations. There are 10 active water-quality monitoring sites in Yankton County. A pipeline streamflow snapshot from the MISSOURI RIVER gauge is also available on this page.

Regional Context

Yankton County has poorer water quality than the average county in South Dakota. Its water score is 15.5 points lower than the state average, suggesting more challenges with contamination control or infrastructure than neighboring counties.

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 Yankton County's water environment

Official EPA Resources for Yankton County

EPA How's My Waterway

Interactive watershed health data for Yankton County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Yankton County

Consumer Confidence Reports (SD)

Annual water quality reports from utilities in South Dakota

Past 5 years

Water Quality Monitoring

Monitoring Sites

10

Active in the past 5 years

Measurements Recorded

428

428 total readings

Most Measured

  • Physical
  • Nutrient
  • Microbiological

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

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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 Yankton County:D — Poor

Elevated violations or significant watershed impairment.

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 Yankton County, South Dakota?
Yankton County, South Dakota has a drinking-water quality grade of F with a score of 41.3/100, based on EPA SDWIS compliance data. The county has 5 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 Yankton County?
Yankton County has 5 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 Yankton County?
EPA's Water Quality Portal records 428 measurements from 10 monitoring sites in Yankton County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Microbiological. 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 Yankton County water compare to the South Dakota average?
Yankton County's SDWIS water quality score of 41.3/100 is lower than the South Dakota state average of 56.8. The average water quality grade across South Dakota is D, based on data from 63 counties with available SDWIS data.
Is tap water safe to drink in Yankton County?
Based on EPA SDWIS data, Yankton County has a water quality grade of F (41.3/100). 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).
Does Yankton County have clean drinking water?
Yankton County has 5 health-based drinking water violations according to EPA records. With a water quality score of 41.3/100 and grade F, 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 Yankton County rank for water quality in South Dakota?
Yankton County ranks #40 out of 63 counties in South Dakota by SDWIS water quality score (1 = best). With a score of 41.3/100, 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

Pennington County

South Dakota

F

41.3

Water score

Meade County

South Dakota

F

38.9

Water score

Edmunds County

South Dakota

F

38.8

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.

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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