Public water system · WA5366578
ActivePattison 500
At a glance
Pattison 500 (PWSID WA5366578) is an active community water system in Thurston County, Washington. It reports serving 4,643 people through 1,865 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 July 2012.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
4,643
Service connections
1,865
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Pattison 500 compare with other water systems in Thurston County?
By EPA's size categories, Pattison 500 is a medium system (3,301 to 10,000 people). Thurston County has 322 active public water systems, and Pattison 500 is the 6th-largest of them by population served. Its population served is about 3.8 times the county average of 1,233 people per system, and accounts for 1.2% of the 397,060 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 Pattison 500 is about 31% 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 Pattison 500?
EPA lists Pattison 500 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. 73 of the 322 active systems in Thurston County (23%) are also owned by a local government.
Does Pattison 500 have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in July 2012. The violations listed here began between January 2002 and July 2012. By type: 10 monitoring and reporting and 2 public notice, recordkeeping or other. The contaminant or rule involved most often is Diquat (3 of them). EPA lists 7 as resolved and 5 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 |
|---|---|---|---|---|
| 2012-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2011-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2007-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Diquatcode 2032 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Diquatcode 2032 | No | Resolved |
| 2005-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Diquatcode 2032 | No | Resolved |
| 2004-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nitratecode 1040 | No | Resolved |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Nickelcode 1036 | No | Archived |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Seleniumcode 1045 | No | Archived |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Bariumcode 1010 | No | Archived |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chromiumcode 1020 | No | Archived |
| 2002-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Cyanidecode 1024 | No | Archived |
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.
Pattison 500: frequently asked questions
Who runs Pattison 500?
Pattison 500 (PWSID WA5366578) is a community water system owned by a local government. It is regulated by the WA state drinking water program.
How many people does Pattison 500 serve?
Pattison 500 reports serving 4,643 people through 1,865 service connections in Thurston County, Washington.
Where does Pattison 500 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 Pattison 500 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 July 2012. 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 Pattison 500'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 July 2012. For current results, consult the system's annual water quality report, EPA ECHO, or the WA state drinking water program.
Where can I find Pattison 500's water quality report?
As a community water system, Pattison 500 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 Thurston County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Olympia City of | Thurston | 126,966 | Community | Groundwater |
| Lacey Water Department | Thurston | 105,178 | Community | Groundwater |
| Tumwater City of | Thurston | 51,802 | Community | Groundwater |
| Yelm City of | Thurston | 17,355 | Community | Groundwater |
| Tanglewilde Thompson Place 600 | Thurston | 7,900 | Community | Groundwater |
| Grand Mound | Thurston | 3,764 | 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, “Pattison 500, PWSID WA5366578, Washington”, https://aquacensus.com/water-systems/washington/pattison-500-wa5366578 (data as of October 1, 2026).