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Federal water data

County water report

Codington County Water Report

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

Water grade

B

Water score

64.1

State rank

#30

of 63

Health violations

1

EPA SDWIS, 5-year lookback

Watershed impaired

Not reported

EPA ATTAINS coverage varies by state

Monitoring sites

17

1,118 recent measurements

Live streamflow

18%

BIG SIOUX RIVER BELOW WATERTOWN, SD

Water at a glance

Key Water Indicators for Codington County

EPA SDWIS

Safety Grade

B

Score: 64.1 / 100

EPA SDWIS

Active Violations

1

5-year health-based lookback

EPA ATTAINS

Watershed Health

Not reported

Coverage varies by state

USGS NWIS

Streamflow Snapshot

18% of mean

BIG SIOUX RIVER BELOW WATERTOWN, SD

EPA WQP

Monitoring Sites

17

1,118 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

B

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

64.1/100

Health violations

1

Health-based violations

Violations per 100K served

4.1

Population-normalized SDWIS rate

Editorial analysis

Understanding Codington County’s Water

Drinking Water Quality Overview

EPA SDWIS

Codington County earns a B grade for drinking water quality, scoring 64.1 out of 100. Over the past five years, EPA SDWIS records 1 health-based violation — a single incident worth monitoring.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2008-09-30T23:45:00.000-05:00) puts BIG SIOUX RIVER BELOW WATERTOWN, SD at 21.0 cfs — well below its long-term average at 18% of mean — low-flow conditions worth noting for water-dependent ecosystems. Streamflow is a leading indicator of drought stress, sediment load, and dilution capacity: low flows concentrate pollutants and warm water temperatures, stressing aquatic life and, in surface-water-dependent systems, the source water quality for treatment plants.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Codington County has moderate coverage with 17 active monitoring sites with 1,118 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 Codington County

Water Verdict

Codington County receives a fair water quality assessment with a grade of B and a score of 64.1 out of 100. The water supply meets baseline federal standards, but there may be periods of elevated contaminant levels or infrastructure concerns worth monitoring.

Violation Context

Codington County has recorded 1 health-based violation, meaning the water system experienced at least one exceedance of federal contaminant limits or treatment requirements. At 4.1 violations per 100,000 people served, this rate is moderate and suggests recurring water quality challenges.

Consumer Guidance

Tap water in Codington County scores well above average for drinking-water safety. Codington County's drinking-water compliance score is 64.1 out of 100. With 1 recorded health violation, the water supply is generally reliable. The violation rate for Codington County is 4.1 per 100,000 people served. Households with infants, pregnant individuals, or immunocompromised members may want to use an NSF 53-certified pitcher filter as a low-cost precaution. With 17 active water-quality monitoring sites in Codington County, data coverage is strong. A pipeline streamflow snapshot from the BIG SIOUX RIVER BELOW WATERTOWN, SD gauge is also available on this page.

Regional Context

Codington County has better water quality than the average county in South Dakota. Its water score is 7.3 points higher than the state average, indicating stronger water system performance relative to 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 Codington County's water environment

Official EPA Resources for Codington County

EPA How's My Waterway

Interactive watershed health data for Codington County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Codington County

Consumer Confidence Reports (SD)

Annual water quality reports from utilities in South Dakota

Past 5 years

Water Quality Monitoring

Monitoring Sites

17

Active in the past 5 years

Measurements Recorded

1.1K

1,118 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).

Live USGS Streamgage

River & Stream Conditions

Current Discharge

21.0cfs

Oct 1, 4:45 AM UTC

vs Long-Term Average

18%

Well below typical

Primary Streamgage

BIG SIOUX RIVER BELOW WATERTOWN, SD

USGS site
06479520
Drainage area
1,000 sq mi
Long-term mean
116 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; the percent-of-typical value compares the latest reading against that average.

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 Codington 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 Codington County, South Dakota?
Codington County, South Dakota has a drinking-water quality grade of B with a score of 64.1/100, based on EPA SDWIS compliance data. The county has 1 health-based drinking water violation over the past 5 years. Watershed health, monitoring records, and streamflow snapshots are reported separately on this page.
Are there any water violations in Codington County?
Codington County has 1 health-based drinking water violation 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 Codington County?
EPA's Water Quality Portal records 1,118 measurements from 17 monitoring sites in Codington 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.
What's happening with rivers in Codington County right now?
Codington County's primary USGS streamgage on the BIG SIOUX RIVER BELOW WATERTOWN, SD has a pipeline snapshot of 21 cubic feet per second — 18% of the long-term mean of 115.93 cfs. This is well below typical — often a signal of drought stress on source water. For the latest gauge feed, visit waterdata.usgs.gov.
How does Codington County water compare to the South Dakota average?
Codington County's SDWIS water quality score of 64.1/100 is higher 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 Codington County?
Based on EPA SDWIS data, Codington County has a water quality grade of B (64.1/100). 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).
Does Codington County have clean drinking water?
Codington County has 1 health-based drinking water violation according to EPA records. With a water quality score of 64.1/100 and grade B, 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 Codington County rank for water quality in South Dakota?
Codington County ranks #30 out of 63 counties in South Dakota by SDWIS water quality score (1 = best). With a score of 64.1/100, 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

Minnehaha County

South Dakota

A

70.4

Water score

Clay County

South Dakota

C

57.7

Water score

Brookings County

South Dakota

C

57.2

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.

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 Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

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