Public water system · WA5351675
ActiveMariani Water System Inc.
At a glance
Mariani Water System Inc. (PWSID WA5351675) is an active community water system in King County, Washington. It reports serving 138 people through 49 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. EPA's records list 3 violations for this system; none is health-based, and the most recent began in January 2022.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
138
Service connections
49
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Mariani Water System Inc. compare with other water systems in King County?
By EPA's size categories, Mariani Water System Inc. is a very small system (500 people or fewer). King County has 214 active public water systems. Its population served is well below the county average of 15,523 people per system, and accounts for less than 0.1% of the 3,321,960 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 Mariani Water System Inc. 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. 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 Mariani Water System Inc.?
EPA lists Mariani Water System Inc. as privately owned. 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. 142 of the 214 active systems in King County (66%) are also privately owned.
Does Mariani Water System Inc. have drinking water violations?
EPA's records list 3 violations for this system; none is health-based, and the most recent began in January 2022. The violations listed here began between October 1991 and January 2022. By type: 3 monitoring and reporting. The contaminant or rule involved most often is Total coliform bacteria (TCR) (2 of them). EPA lists 2 as archived and 1 as resolved. 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. 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 |
|---|---|---|---|---|
| 2022-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 1993-02-01 | Monitoring and reportingMonitoring, Routine Major (TCR) · code 23 | Total coliform bacteria (TCR)code 3100 | No | Archived |
| 1991-10-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Archived |
All 3 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.
Mariani Water System Inc.: frequently asked questions
Who runs Mariani Water System Inc.?
Mariani Water System Inc. (PWSID WA5351675) is a community water system privately owned. It is regulated by the WA state drinking water program.
How many people does Mariani Water System Inc. serve?
Mariani Water System Inc. reports serving 138 people through 49 service connections in King County, Washington.
Where does Mariani Water System Inc. 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 Mariani Water System Inc. have any drinking water violations?
EPA's records list 3 violations for this system; none is health-based, and the most recent began in January 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 Mariani Water System Inc.'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 3 violations for this system; none is health-based, and the most recent began in January 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 Mariani Water System Inc.'s water quality report?
As a community water system, Mariani Water System Inc. 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 King County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Seattle Public Utilities | King | 1,161,961 | Community | Surface water |
| Bellevue City of | King | 321,349 | Community | Purchased surface water |
| Kent Water Department | King | 166,421 | Community | Purchased surface water |
| Redmond Water System City of | King | 163,335 | Community | Purchased surface water |
| Lakehaven Water and Sewer District | King | 148,809 | Community | Purchased surface water |
| Renton City of | King | 108,091 | 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, “Mariani Water System Inc., PWSID WA5351675, Washington”, https://aquacensus.com/water-systems/washington/mariani-water-system-inc-wa5351675 (data as of October 1, 2026).