Public water system · SD4600423

Active

Yankton

At a glance

Yankton (PWSID SD4600423) is an active community water system in Yankton County, South Dakota. It reports serving 15,411 people through 5,500 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 10 are health-based, and the most recent began in January 2020.

Dataset updated October 2026 . Source: EPA SDWIS/ECHO public records.

Population served

15,411

Service connections

5,500

Primary source

Groundwater

System type

CWS

Community water system

System record

PWSIDSD4600423

System typeCommunity water system

Activity statusActive

Population served15,411

Service connections5,500

Primary water sourceGroundwater

Owner typeLocal government

Primacy agencySD state drinking water program

City servedYankton

StateSouth Dakota

ZIP57078

CountyYankton County

How does Yankton compare with other water systems in Yankton County?

By EPA's size categories, Yankton is a large system (10,001 to 100,000 people). Yankton County has 9 active public water systems, and Yankton is the largest of them by population served. Its population served is about 8.2 times the county average of 1,883 people per system, and accounts for 91% of the 16,948 people reported by systems filed under the county. Across South Dakota, the 699 active systems average 1,387 people each. Nationally, the average active community water system reports serving 6,703 people, so Yankton is about 130% above that figure.

What does “community water system” mean?

A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. South Dakota has 510 active community water systems, 73% of the state's 699 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 431 South Dakota systems (62%) list groundwater as their primary source.

Who owns and regulates Yankton?

EPA lists Yankton as owned by a local government. The SD state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 6 of the 9 active systems in Yankton County (67%) are also owned by a local government.

Does Yankton have drinking water violations?

Of the 12 most recent violations in EPA's records, 10 are health-based, and the most recent began in January 2020. The violations listed here began between April 2008 and January 2020. By type: 8 contaminant level above the legal limit, 2 required treatment not met and 2 monitoring and reporting. The contaminant or rule involved most often is Total trihalomethanes (TTHM) (8 of them). EPA lists 12 as resolved. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed.

Began	Violation	Contaminant or rule	Health-based	Status
2020-01-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2019-10-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2019-07-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2019-04-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2016-04-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2011-02-01	Required treatment not metTreatment Technique No Certif. Operator · code 12	Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400	Yes	Resolved
2010-02-01	Required treatment not metTreatment Technique No Certif. Operator · code 12	Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400	Yes	Resolved
2010-01-02	Monitoring and reportingFailure Submit IDSE/Subpart V Plan Rpt · code 35	Stage 2 Disinfectants and Disinfection Byproducts Rulecode 0600	No	Resolved
2009-01-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2008-10-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2008-07-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Total trihalomethanes (TTHM)code 2950	Yes	Resolved
2008-04-01	Monitoring and reportingMonitoring, Regular · code 03	Picloramcode 2040	No	Resolved

The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.

Yankton: frequently asked questions

Who runs Yankton?

Yankton (PWSID SD4600423) is a community water system owned by a local government. It is regulated by the SD state drinking water program.

How many people does Yankton serve?

Yankton reports serving 15,411 people through 5,500 service connections in Yankton County, South Dakota.

Where does Yankton get its water?

EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.

Does Yankton have any drinking water violations?

Of the 12 most recent violations in EPA's records, 10 are health-based, and the most recent began in January 2020. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.

Is Yankton's water safe to drink?

AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, 10 are health-based, and the most recent began in January 2020. For current results, consult the system's annual water quality report, EPA ECHO, or the SD state drinking water program.

Where can I find Yankton's water quality report?

As a community water system, Yankton must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.

Other water systems in Yankton County

Water system	County	Population served	Type	Source
Gayville	Yankton	392	Community	Purchased groundwater
3 Sons Rv Park	Yankton	339	Transient non-community	Groundwater
Mission Hill	Yankton	190	Community	Purchased surface water
East Winds Court, Inc..	Yankton	180	Community	Purchased surface water
Volin	Yankton	161	Community	Purchased surface water
Lesterville	Yankton	115	Community	Purchased surface water

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About this data

Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.

Cite as: AquaCensus, “Yankton, PWSID SD4600423, South Dakota”, https://aquacensus.com/water-systems/south-dakota/yankton-sd4600423 (data as of October 1, 2026).