Public water system · IA4070022
ActiveWilliams Water Supply
At a glance
Williams Water Supply (PWSID IA4070022) is an active community water system in Hamilton County, Iowa. It reports serving 315 people through 192 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 4 violations for this system; none is health-based, and the most recent began in April 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
315
Service connections
192
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Williams Water Supply compare with other water systems in Hamilton County?
By EPA's size categories, Williams Water Supply is a very small system (500 people or fewer). Hamilton County has 13 active public water systems. Its population served is well below the county average of 1,099 people per system, and accounts for 2.2% of the 14,289 people reported by systems filed under the county. Across Iowa, the 1,828 active systems average 1,718 people each. Nationally, the average active community water system reports serving 6,703 people, so Williams Water Supply 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. Iowa has 1,084 active community water systems, 59% of the state's 1,828 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 1,502 Iowa systems (82%) list groundwater as their primary source.
Who owns and regulates Williams Water Supply?
EPA lists Williams Water Supply as owned by a local government. The IA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 8 of the 13 active systems in Hamilton County (62%) are also owned by a local government.
Does Williams Water Supply have drinking water violations?
EPA's records list 4 violations for this system; none is health-based, and the most recent began in April 2025. The violations listed here began between July 1986 and April 2025. By type: 4 monitoring and reporting. The contaminants or rules involved are Nitrate, Haloacetic acids (HAA5), Total trihalomethanes (TTHM) and Fluoride. EPA lists 3 as resolved and 1 as archived. 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. Archived means the violation was not marked resolved but is more than five years past the end of the noncompliance period, so it no longer counts toward current compliance status.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-04-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Archived |
| 2022-05-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2022-05-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 1986-07-01 | Monitoring and reportingMonitoring, Regular · code 03 | Fluoridecode 1025 | No | Resolved |
All 4 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.
Williams Water Supply: frequently asked questions
Who runs Williams Water Supply?
Williams Water Supply (PWSID IA4070022) is a community water system owned by a local government. It is regulated by the IA state drinking water program.
How many people does Williams Water Supply serve?
Williams Water Supply reports serving 315 people through 192 service connections in Hamilton County, Iowa.
Where does Williams Water Supply 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 Williams Water Supply have any drinking water violations?
EPA's records list 4 violations for this system; none is health-based, and the most recent began in April 2025. 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 Williams Water Supply'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. EPA's records list 4 violations for this system; none is health-based, and the most recent began in April 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the IA state drinking water program.
Where can I find Williams Water Supply's water quality report?
As a community water system, Williams Water Supply 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 Hamilton County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Webster City Water Supply | Hamilton | 7,825 | Community | Groundwater |
| Flying J No 572 | Hamilton | 1,892 | Non-transient non-community | Groundwater |
| Jewell Water Supply | Hamilton | 1,216 | Community | Groundwater |
| Stratford Muni Water Dept | Hamilton | 707 | Community | Groundwater |
| Williams Travel Center | Hamilton | 610 | Transient non-community | Groundwater |
| Ellsworth Public Water Supply | Hamilton | 514 | 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, “Williams Water Supply, PWSID IA4070022, Iowa”, https://aquacensus.com/water-systems/iowa/williams-water-supply-ia4070022 (data as of October 1, 2026).