Public water system · SD4600316

Active

Walnut Park

At a glance

Walnut Park (PWSID SD4600316) is an active community water system in Lawrence County, South Dakota. It reports serving 180 people through 72 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 7 are health-based, and the most recent began in October 2024.

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

Population served

180

Service connections

Primary source

Groundwater

System type

CWS

Community water system

System record

PWSIDSD4600316

System typeCommunity water system

Activity statusActive

Population served180

Service connections72

Primary water sourceGroundwater

Owner typePrivate

Primacy agencySD state drinking water program

City servedSpearfish

StateSouth Dakota

ZIP57783

CountyLawrence County

How does Walnut Park compare with other water systems in Lawrence County?

By EPA's size categories, Walnut Park is a very small system (500 people or fewer). Lawrence County has 73 active public water systems. Its population served is about half of the county average of 373 people per system, and accounts for 0.7% of the 27,194 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 Walnut Park is well below 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 Walnut Park?

EPA lists Walnut Park as privately owned. 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. 60 of the 73 active systems in Lawrence County (82%) are also privately owned.

Does Walnut Park have drinking water violations?

Of the 12 most recent violations in EPA's records, 7 are health-based, and the most recent began in October 2024. The violations listed here began between July 2013 and October 2024. By type: 7 required treatment not met, 3 monitoring and reporting, 1 reporting and 1 monitoring. The contaminant or rule involved most often is Stage 1 Disinfectants and Disinfection Byproducts Rule (4 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
2024-10-17	Required treatment not metLSL Inventory · code 2E	Lead and Copper Rule Revisionscode 5200	Yes	Resolved
2024-10-17	ReportingLSL Reporting · code 4G	Lead and Copper Rule Revisionscode 5200	No	Resolved
2019-02-01	Required treatment not metTreatment Technique No Certif. Operator · code 12	Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400	Yes	Resolved
2018-10-02	Required treatment not metFailure To Address Deficiency · code 45	Groundwater Rulecode 0700	Yes	Resolved
2018-05-16	Required treatment not metTreatment Technique No Certif. Operator · code 12	Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400	Yes	Resolved
2018-05-01	MonitoringMonitoring, Routine (RTCR) · code 3A	Revised Total Coliform Rulecode 8000	No	Resolved
2018-04-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Chlorinecode 0999	No	Resolved
2017-05-01	Required treatment not metTreatment Technique No Certif. Operator · code 12	Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400	Yes	Resolved
2016-08-19	Required treatment not metFailure To Address Deficiency · code 45	Groundwater Rulecode 0700	Yes	Resolved
2016-02-01	Required treatment not metTreatment Technique No Certif. Operator · code 12	Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400	Yes	Resolved
2013-09-01	Monitoring and reportingMonitoring, Routine Major (TCR) · code 23	Total coliform bacteria (TCR)code 3100	No	Resolved
2013-07-01	Monitoring and reportingMonitoring and Reporting (DBP) · code 27	Chlorinecode 0999	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.

Walnut Park: frequently asked questions

Who runs Walnut Park?

Walnut Park (PWSID SD4600316) is a community water system privately owned. It is regulated by the SD state drinking water program.

How many people does Walnut Park serve?

Walnut Park reports serving 180 people through 72 service connections in Lawrence County, South Dakota.

Where does Walnut Park 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 Walnut Park have any drinking water violations?

Of the 12 most recent violations in EPA's records, 7 are health-based, and the most recent began in October 2024. 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 Walnut Park'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, 7 are health-based, and the most recent began in October 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the SD state drinking water program.

Where can I find Walnut Park's water quality report?

As a community water system, Walnut Park 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 Lawrence County

Water system	County	Population served	Type	Source
Spearfish	Lawrence	13,803	Community	Groundwater
Lead	Lawrence	2,982	Community	Purchased surface water
Deadwood	Lawrence	1,156	Community	Purchased surface water
Whitewood	Lawrence	879	Community	Groundwater
Guadalajara Mexican Restaurant	Lawrence	630	Transient non-community	Groundwater
Spearfish Canyon Resort LLC	Lawrence	492	Transient non-community	Groundwater

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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, “Walnut Park, PWSID SD4600316, South Dakota”, https://aquacensus.com/water-systems/south-dakota/walnut-park-sd4600316 (data as of October 1, 2026).