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RIMROCK RIDGE WATER ASSOCIATION

PWS ID: SD4602084 · RAPID CITY, South Dakota 57709

RIMROCK RIDGE WATER ASSOCIATION serves 35 people in RAPID CITY, South Dakota using Groundwater water sources. It has 99 recorded EPA violations, including 12 health-based violations. No PFAS contamination was detected in UCMR5 testing.

Water Quality Snapshot: RIMROCK RIDGE WATER ASSOCIATION

RIMROCK RIDGE WATER ASSOCIATION is a private-owned community water system that delivers drinking water to 35 residents in RAPID CITY, South Dakota (Pennington County) through 16 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 99 total violations for this system , of which 12 (12%) are health-based — meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 83 monitoring and reporting violations are on file. The most recent violation on record dates to 1995.

The most frequently cited contaminant at this system is Coliform (TCR), recorded in 16 violations (MR). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

Across South Dakota, EPA tracks 654 public water systems serving 915,901 people, with 56,254 cumulative violations and 8,399 health-based violations on record. About 92% of systems in the state carry at least one violation, and state-wide the average per system is 86 violations. RIMROCK RIDGE WATER ASSOCIATION's 99 violations sit above the South Dakota average. Statewide, 42 of 49 UCMR5-tested systems have reported PFAS detections (85.7%). All figures above are sourced directly from EPA SDWIS and UCMR5 public data releases and are updated as EPA publishes new reporting cycles.

Population Served
35
Total Violations
99
Health-Based Violations
12
Water Source
Groundwater

System Details

System Type
Community
Owner Type
Private
Connections
16
County
Pennington
School/Daycare
No
MCL Violations
12
Monitoring Violations
83
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Coliform (TCR) MR 16 1994
Coliform (TCR) MCL 12 1995
Lead and Copper Rule MR 4 1993
Nitrate MR 3 1995
Combined Radium (-226 and -228) MR 2 1987
Arsenic MR 2 1988
Barium MR 2 1988
Cadmium MR 2 1988
Chromium MR 2 1988
Fluoride MR 2 1988
Vinyl chloride MR 2 1993
cis-1,2-Dichloroethylene MR 2 1993
Tetrachloroethylene MR 2 1993
DICHLOROMETHANE MR 2 1993
1,1,2-Trichloroethane MR 2 1993
1,1-Dichloroethylene MR 2 1993
CHLOROBENZENE MR 2 1993
o-Dichlorobenzene MR 2 1993
trans-1,2-Dichloroethylene MR 2 1993
1,2-Dichloropropane MR 2 1993
Benzene MR 2 1993
Trichloroethylene MR 2 1993
Toluene MR 2 1993
1,2,4-Trichlorobenzene MR 2 1993
Gross Alpha, Excl. Radon and U MR 2 1987
p-Dichlorobenzene MR 2 1993
Xylenes, Total MR 2 1993
Carbon tetrachloride MR 2 1993
1,2-Dichloroethane MR 2 1993
1,1,1-Trichloroethane MR 2 1993

Verify This Water System

The figures above are aggregated from EPA's public databases. To verify the underlying records — or to file a complaint, request a Consumer Confidence Report, or check current monitoring status — go directly to the federal and state regulators that enforce the Safe Drinking Water Act for RIMROCK RIDGE WATER ASSOCIATION.

Federal Source of Truth

EPA SDWIS — Federal Reports

EPA's Safe Drinking Water Information System (SDWIS) holds the federal compliance record for every regulated public water system. Open the system-level report by PWS ID:

View PWS ID SD4602084 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

South Dakota Drinking Water Authority

South Dakota's primacy agency administers the Safe Drinking Water Act locally. Search EPA SDWIS for the current state contact, or use the state's public health or environment department portal.

Find SD regulator via EPA SDWIS

Violation Timeline

Each row links to the EPA SDWIS public record for verification. Cross-reference the contaminant code on EPA's federal report to see violation dates, return-to-compliance status, and enforcement actions.

Year (latest) Contaminant Category Count EPA Record
1995 Coliform (TCR) MCL 12 SDWIS / SD4602084 / 3100
1995 Nitrate MR 3 SDWIS / SD4602084 / 1040
1994 Coliform (TCR) MR 16 SDWIS / SD4602084 / 3100
1993 Lead and Copper Rule MR 4 SDWIS / SD4602084 / 5000
1993 Vinyl chloride MR 2 SDWIS / SD4602084 / 2976
1993 cis-1,2-Dichloroethylene MR 2 SDWIS / SD4602084 / 2380
1993 Tetrachloroethylene MR 2 SDWIS / SD4602084 / 2987
1993 DICHLOROMETHANE MR 2 SDWIS / SD4602084 / 2964
1993 1,1,2-Trichloroethane MR 2 SDWIS / SD4602084 / 2985
1993 1,1-Dichloroethylene MR 2 SDWIS / SD4602084 / 2977
1993 CHLOROBENZENE MR 2 SDWIS / SD4602084 / 2989
1993 o-Dichlorobenzene MR 2 SDWIS / SD4602084 / 2968
1993 trans-1,2-Dichloroethylene MR 2 SDWIS / SD4602084 / 2979
1993 1,2-Dichloropropane MR 2 SDWIS / SD4602084 / 2983
1993 Benzene MR 2 SDWIS / SD4602084 / 2990

How RIMROCK RIDGE WATER ASSOCIATION Compares

Cross-reference this system's record against state averages and the federal MCL framework for context.

Metric RIMROCK RIDGE WATER ASSOCIATION South Dakota avg Federal benchmark
Total violations 99 86 SDWA compliance — any non-zero count is a recorded breach
Health-based violations 12 12.8 Indicates a contaminant exceeded a federal MCL
PFAS detection None 85.7% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 35 1,400 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 654 regulated public water systems in South Dakota.

Federal MCL reference — Safe Drinking Water Act thresholds ▼
Contaminant Federal MCL / Action Level Note
Lead 0 mg/L (Action Level: 0.015 mg/L) Lead and Copper Rule treatment technique
Arsenic 0.010 mg/L (10 ppb) Health-based MCL since 2006
Total Coliform Treatment technique (RTCR) Indicator organism, monitoring trigger
PFOA / PFOS (PFAS) 4.0 ppt each (final 2024 rule) Compliance deadline 2029
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is RIMROCK RIDGE WATER ASSOCIATION water safe to drink? ▼
RIMROCK RIDGE WATER ASSOCIATION (PWS ID: SD4602084) has 99 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 35 people using Groundwater sources.
How many people does RIMROCK RIDGE WATER ASSOCIATION serve? ▼
RIMROCK RIDGE WATER ASSOCIATION serves 35 people in RAPID CITY, South Dakota. It is a Private-owned system using Groundwater water sources with 16 service connections.
What type of violations does RIMROCK RIDGE WATER ASSOCIATION have? ▼
RIMROCK RIDGE WATER ASSOCIATION has 99 total violations: 12 health-based violations (MCL exceedances or treatment failures), 83 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in RIMROCK RIDGE WATER ASSOCIATION water? ▼
No PFAS testing data is available for RIMROCK RIDGE WATER ASSOCIATION under the EPA's UCMR5 monitoring program.
What water source does RIMROCK RIDGE WATER ASSOCIATION use? ▼
RIMROCK RIDGE WATER ASSOCIATION uses Groundwater as its primary water source. It is classified as a Community Water System (CWS), serving residential populations year-round.
Where does this data come from? ▼
All data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS tracks compliance for all public water systems regulated under the Safe Drinking Water Act.

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Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025. This data is provided for informational purposes only.

Read our methodology — how this data is sourced, computed, and verified.

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