Public water system · WA5356300
ActiveMoses Lake City of
At a glance
City of Moses Lake (PWSID WA5356300) is an active community water system in Grant County, Washington. It reports serving 32,428 people through 13,420 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in October 2022.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
32,428
Service connections
13,420
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does City of Moses Lake compare with other water systems in Grant County?
By EPA's size categories, City of Moses Lake is a large system (10,001 to 100,000 people). Grant County has 265 active public water systems, and City of Moses Lake is the largest of them by population served. Its population served is about 60 times the county average of 543 people per system, and accounts for 23% of the 143,944 people reported by systems filed under the county. Across Washington, the 4,705 active systems average 2,172 people each. Nationally, the average active community water system reports serving 6,703 people, so City of Moses Lake is about 4.8 times 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. Washington has 2,392 active community water systems, 51% of the state's 4,705 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 4,370 Washington systems (93%) list groundwater as their primary source.
Who owns and regulates City of Moses Lake?
EPA lists City of Moses Lake as owned by a local government. The WA state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 26 of the 265 active systems in Grant County (9.8%) are also owned by a local government.
Does City of Moses Lake have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in October 2022. The violations listed here began between October 2022 and October 2022. By type: 12 monitoring and reporting. The contaminants or rules involved are Dichloromethane, cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene and 1,2,4-Trichlorobenzene. 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 |
|---|---|---|---|---|
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Dichloromethanecode 2964 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | cis-1,2-Dichloroethylenecode 2380 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | trans-1,2-Dichloroethylenecode 2979 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2,4-Trichlorobenzenecode 2378 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2-Dichloropropanecode 2983 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,2-Trichloroethanecode 2985 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,1-Trichloroethanecode 2981 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Vinyl chloridecode 2976 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,2-Dichloroethanecode 2980 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Trichloroethylenecode 2984 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | Carbon tetrachloridecode 2982 | No | Resolved |
| 2022-10-01 | Monitoring and reportingMonitoring, Regular · code 03 | o-Dichlorobenzenecode 2968 | 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.
City of Moses Lake: frequently asked questions
Who runs City of Moses Lake?
City of Moses Lake (PWSID WA5356300) is a community water system owned by a local government. It is regulated by the WA state drinking water program.
How many people does City of Moses Lake serve?
City of Moses Lake reports serving 32,428 people through 13,420 service connections in Grant County, Washington.
Where does City of Moses Lake 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 City of Moses Lake have any drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in October 2022. 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 City of Moses Lake'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, none is health-based, and the most recent began in October 2022. For current results, consult the system's annual water quality report, EPA ECHO, or the WA state drinking water program.
Where can I find City of Moses Lake's water quality report?
As a community water system, City of Moses Lake 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 Grant County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Gorge Amphitheatre | Grant | 25,119 | Transient non-community | Groundwater |
| Ephrata Water Department | Grant | 8,718 | Community | Groundwater |
| Quincy Water Department City of | Grant | 8,415 | Community | Groundwater |
| Mattawa City of | Grant | 5,370 | Community | Groundwater |
| Sun Lakes State Park | Grant | 4,858 | Transient non-community | Groundwater |
| Warden City of | Grant | 4,674 | 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, “Moses Lake City of, PWSID WA5356300, Washington”, https://aquacensus.com/water-systems/washington/moses-lake-city-of-wa5356300 (data as of October 1, 2026).