Public water system · SD4602135
ActiveOaks Water Users Association
At a glance
Oaks Water Users Association (PWSID SD4602135) is an active community water system in Pennington County, South Dakota. It reports serving 180 people through 73 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, 2 are health-based, and the most recent began in February 2015.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
180
Service connections
73
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Oaks Water Users Association compare with other water systems in Pennington County?
By EPA's size categories, Oaks Water Users Association is a very small system (500 people or fewer). Pennington County has 150 active public water systems. Its population served is well below the county average of 930 people per system, and accounts for 0.1% of the 139,467 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 Oaks Water Users Association 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 Oaks Water Users Association?
EPA lists Oaks Water Users Association 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. 134 of the 150 active systems in Pennington County (89%) are also privately owned.
Does Oaks Water Users Association have drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in February 2015. The violations listed here began between January 1998 and February 2015. By type: 10 monitoring and reporting, 1 required treatment not met and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Total coliform bacteria (TCR) (3 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 |
|---|---|---|---|---|
| 2015-02-01 | Required treatment not metTreatment Technique No Certif. Operator · code 12 | Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400 | Yes | Resolved |
| 2001-07-01 | Monitoring and reportingMonitoring, Regular · code 03 | Combined Radium (-226 and -228)code 4010 | No | Resolved |
| 2001-07-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Resolved |
| 2001-04-01 | Monitoring and reportingMonitoring, Repeat Major (TCR) · code 25 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2000-09-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1999-02-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | trans-1,2-Dichloroethylenecode 2979 | No | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Styrenecode 2996 | No | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2-Dichloropropanecode 2983 | No | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Xylenes, Totalcode 2955 | No | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Carbon tetrachloridecode 2982 | No | Resolved |
| 1998-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | cis-1,2-Dichloroethylenecode 2380 | 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.
Oaks Water Users Association: frequently asked questions
Who runs Oaks Water Users Association?
Oaks Water Users Association (PWSID SD4602135) is a community water system privately owned. It is regulated by the SD state drinking water program.
How many people does Oaks Water Users Association serve?
Oaks Water Users Association reports serving 180 people through 73 service connections in Pennington County, South Dakota.
Where does Oaks Water Users Association 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 Oaks Water Users Association have any drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in February 2015. 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 Oaks Water Users Association'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, 2 are health-based, and the most recent began in February 2015. For current results, consult the system's annual water quality report, EPA ECHO, or the SD state drinking water program.
Where can I find Oaks Water Users Association's water quality report?
As a community water system, Oaks Water Users Association 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 Pennington County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Rapid City | Pennington | 72,009 | Community | Surface water |
| Box Elder | Pennington | 14,000 | Community | Groundwater |
| Rapid Valley Sanitary District | Pennington | 11,408 | Community | Surface water |
| Ellsworth Afb | Pennington | 9,100 | Community | Purchased surface water |
| Nps-Mount Rushmore National Memorial | Pennington | 4,100 | Non-transient non-community | Groundwater |
| Colonial Pine Hills Sanitary Distric | Pennington | 1,200 | 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, “Oaks Water Users Association, PWSID SD4602135, South Dakota”, https://aquacensus.com/water-systems/south-dakota/oaks-water-users-association-sd4602135 (data as of October 1, 2026).