Public water system · WA5366565
ActivePatterson Addition
At a glance
Patterson Addition (PWSID WA5366565) is an active community water system in Spokane County, Washington. It reports serving 22 people through 20 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in February 2026.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
22
Service connections
20
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Patterson Addition compare with other water systems in Spokane County?
By EPA's size categories, Patterson Addition is a very small system (500 people or fewer). Spokane County has 163 active public water systems. Its population served is well below the county average of 3,871 people per system, and accounts for less than 0.1% of the 631,008 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 Patterson Addition 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 Patterson Addition?
EPA lists Patterson Addition 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. 93 of the 163 active systems in Spokane County (57%) are also privately owned.
Does Patterson Addition have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in February 2026. The violations listed here began between July 2015 and February 2026. By type: 7 monitoring, 3 public notice, recordkeeping or other and 2 monitoring and reporting. The contaminant or rule involved most often is Revised Total Coliform Rule (7 of them). 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 |
|---|---|---|---|---|
| 2026-02-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2026-01-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2024-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2023-09-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2023-08-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2023-03-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2022-07-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2022-03-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2021-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2018-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2015-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2015-07-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | 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.
Patterson Addition: frequently asked questions
Who runs Patterson Addition?
Patterson Addition (PWSID WA5366565) is a community water system privately owned. It is regulated by the WA state drinking water program.
How many people does Patterson Addition serve?
Patterson Addition reports serving 22 people through 20 service connections in Spokane County, Washington.
Where does Patterson Addition 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 Patterson Addition 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 February 2026. 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 Patterson Addition'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 February 2026. For current results, consult the system's annual water quality report, EPA ECHO, or the WA state drinking water program.
Where can I find Patterson Addition's water quality report?
As a community water system, Patterson Addition 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 Spokane County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Spokane City of | Spokane | 346,138 | Community | Groundwater |
| Whitworth Water District 2 | Spokane | 26,883 | Community | Groundwater |
| Vera Water & Power | Spokane | 24,692 | Community | Groundwater |
| Consolidated Irrig Dist 19 System 2 | Spokane | 21,220 | Community | Groundwater |
| Spo Co Water Dist 3 Sys 1 | Spokane | 19,035 | Community | Groundwater |
| Modern Electric Water Co | Spokane | 18,487 | 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, “Patterson Addition, PWSID WA5366565, Washington”, https://aquacensus.com/water-systems/washington/patterson-addition-wa5366565 (data as of October 1, 2026).