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Transient Non-Community Water System · PWS IA1700352

Oakwood Park Water Association

Mason City, Iowa 50401 - drinking water served from groundwater sources to 66 people, tracked in EPA SDWIS and UCMR5.

66
People served
278
EPA violations
140
Health-based
Untested
UCMR5 result

The verdict

EPA records 278 drinking-water violations at Oakwood Park Water Association, 50% of them health-based - above the Iowa per-system average.

278
Total EPA violations on record
50%
Health-based (MCL / treatment failure)
66
People served by this system
N/A
PFAS compounds detected (UCMR5)

Water Quality Snapshot: Oakwood Park Water Association

Oakwood Park Water Association is a private-owned transient non-community water system that delivers drinking water to 66 residents in Mason City, Iowa (Cerro Gordo County) through 33 service connections. Its water is drawn from groundwater sources. EPA's Safe Drinking Water Information System records 278 total violations for this system , of which 140 (50%) are health-based, meaning a contaminant exceeded an EPA Maximum Contaminant Level or a required treatment technique failed. A further 123 monitoring and reporting violations are on file. The most recent violation on record dates to 2017.

The most frequently cited contaminant at this system is Arsenic, recorded in 113 violations (MCL, health-based). This system has not yet been sampled under EPA's UCMR5 PFAS monitoring program, so no PFAS detection data is available here.

Across Iowa, EPA tracks 1,795 public water systems serving 3,114,444 people, with 138,271 cumulative violations and 27,946 health-based violations on record. About 95% of systems in the state carry at least one violation, and state-wide the average per system is 77 violations. Statewide, 127 of 152 UCMR5-tested systems have reported PFAS detections (83.6%).

Oakwood Park Water Association's 278 violations sit above the Iowa average.

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
66
Total Violations
278
Health-Based Violations
140
Water Source
Groundwater

System Details

System Type
Transient Non-Community
Owner Type
Private
Connections
33
County
Cerro Gordo
School/Daycare
No
MCL Violations
140
Monitoring Violations
123
Treatment Tech Violations
0

Violation History

Contaminant violations recorded by EPA.

Contaminant Category Count Latest
Arsenic MCL 113 2003
Coliform (TCR) MR 60 1998
Coliform (TCR) MCL 27 2000
Arsenic MR 17 1998
Lead and Copper Rule MR 9 2017
Barium MR 6 1987
Mercury MR 6 1987
Selenium MR 6 1987
Chromium MR 6 1987
Fluoride MR 6 1987
Antimony, Total MR 4 1994
Cadmium MR 3 1987

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 Oakwood Park 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 IA1700352 on SDWIS

Source: EPA SDWIS Federal Reports Search

State Regulator

Iowa Drinking Water Authority

Iowa'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 IA 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
2017 Lead and Copper Rule MR 9 SDWIS / IA1700352 / 5000
2003 Arsenic MCL 113 SDWIS / IA1700352 / 1005
2000 Coliform (TCR) MCL 27 SDWIS / IA1700352 / 3100
1998 Coliform (TCR) MR 60 SDWIS / IA1700352 / 3100
1998 Arsenic MR 17 SDWIS / IA1700352 / 1005
1994 Antimony, Total MR 4 SDWIS / IA1700352 / 1074
1987 Barium MR 6 SDWIS / IA1700352 / 1010
1987 Mercury MR 6 SDWIS / IA1700352 / 1035
1987 Selenium MR 6 SDWIS / IA1700352 / 1045
1987 Chromium MR 6 SDWIS / IA1700352 / 1020
1987 Fluoride MR 6 SDWIS / IA1700352 / 1025
1987 Cadmium MR 3 SDWIS / IA1700352 / 1015

How Oakwood Park Water Association Compares

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

Metric Oakwood Park Water Association Iowa avg Federal benchmark
Total violations 278 77 SDWA compliance, any non-zero count is a recorded breach
Health-based violations 140 15.6 Indicates a contaminant exceeded a federal MCL
PFAS detection None 83.6% EPA final rule (2024): PFOA/PFOS MCL = 4.0 ppt
Population served 66 1,735 Sizing context for compliance burden

Sources: EPA SDWIS and EPA National Primary Drinking Water Regulations (40 CFR Part 141). State averages computed across 1,795 regulated public water systems in Iowa.

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 (EPA proposed extending to 2031, not yet final as of May 2026)
Nitrate (as N) 10 mg/L Acute health risk for infants

Frequently Asked Questions

Is Oakwood Park Water Association water safe to drink? ▼
Oakwood Park Water Association (PWS ID: IA1700352) has 278 recorded violations in the EPA SDWIS database. No PFAS contamination was detected in UCMR5 testing. This system serves 66 people using Groundwater sources.
How many people does Oakwood Park Water Association serve? ▼
Oakwood Park Water Association serves 66 people in Mason City, Iowa. It is a Private-owned system using Groundwater water sources with 33 service connections.
What type of violations does Oakwood Park Water Association have? ▼
Oakwood Park Water Association has 278 total violations: 140 health-based violations (MCL exceedances or treatment failures), 123 monitoring/reporting violations, and 0 treatment technique violations. Health-based violations indicate contaminant levels exceeded EPA safe limits.
Has PFAS been detected in Oakwood Park Water Association water? ▼
No PFAS testing data is available for Oakwood Park Water Association under the EPA's UCMR5 monitoring program.
What water source does Oakwood Park Water Association use? ▼
Oakwood Park Water Association uses Groundwater as its primary water source. It is classified as a Transient Non-Community Water System, serving transient populations.
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.
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.

Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This system's figures are rendered directly from EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.