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Columbia County, Oregon — public water systems

At a glance

57 active public water systems are filed under Columbia County, Oregon in EPA's SDWIS records, together reporting 40,191 people served. The largest is City of St Helens, which reports serving 13,410 people. 37 are community water systems serving people where they live; the other 20 are non-community systems, such as schools, workplaces, campgrounds and gas stations with their own supply.

Dataset updated . Source: EPA SDWIS/ECHO, refreshed quarterly.

Active systems

57

Population served

40.2K

Community systems

37

Groundwater share

84.2%

How does Columbia County compare with other Oregon counties?

Columbia County has the 15th-most active public water systems among the 57 counties listed for active Oregon systems in EPA records; among the 38 with 3 or more systems, the median has 41. Its systems report 40,191 people served in total, the 19th-largest county figure in the state and 1% of the statewide total. The average system here reports serving 705 people, about 56% below the Oregon average of 1,587. Population figures are what each system reports; people served by more than one system, such as a wholesaler and the town that buys from it, are counted by each.

Where does Columbia County's drinking water come from?

By primary water source, Columbia County's active systems draw on groundwater (47, 82%), surface water (9, 16%) and groundwater under influence of surface water (1, 1.8%). Overall, 84% rely mainly on groundwater (including purchased groundwater) and 16% on surface water, compared with 88% and 12% across Oregon. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, City of St Helens, draws primarily on groundwater under influence of surface water.

What kinds of water systems operate in Columbia County?

Columbia County's active systems break down as 37 community systems (65%), 6 non-transient non-community systems (11%) and 14 transient non-community systems (25%). 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. A non-transient non-community water system regularly serves at least 25 of the same people for more than six months a year, but not where they live. Schools, factories, office buildings and hospitals with their own supply are typical examples. A transient non-community water system serves places where people do not stay long, such as gas stations and campgrounds, and regularly serves at least 25 people a day for at least 60 days a year. EPA lists their owner types as private (75%), local government (23%) and public/private partnership (1.8%).

The 50 largest water systems in Columbia County

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Active public water systems in Columbia County, Oregon
#Water systemCountyPopulation servedTypeSource
1St Helens, City ofColumbia13,410CommunityGroundwater under influence of surface water
2Scappoose, City ofColumbia8,710CommunitySurface water
3Mcnulty Water PUDColumbia2,500CommunityGroundwater
4Clatskanie, City ofColumbia2,188CommunitySurface water
5Vernonia, City ofColumbia2,100CommunitySurface water
6Warren Water AssociationColumbia2,050CommunityGroundwater
7Columbia City Mun WaterworksColumbia1,995CommunityGroundwater
8City of RainierColumbia1,932CommunitySurface water
9Rainier Sd #13Columbia950Non-transient non-communityGroundwater
10Western Hills Mh EstatesColumbia375CommunityGroundwater
11Fishhawk Lake Reserve and CommunityColumbia350CommunitySurface water
12Quincy Water AssociationColumbia300CommunityGroundwater
13Columbia Co Pks-Hudson/ParcherColumbia200Transient non-communityGroundwater
14Columbia Co Pks-Camp WilkersonColumbia200Transient non-communityGroundwater
15Midland Water AssociationColumbia160CommunitySurface water
16Rainier Or LDS ChurchColumbia150Transient non-communityGroundwater
17Columbia Co Pks-Big EddyColumbia125Transient non-communityGroundwater
18Columbia Acres Water AssocColumbia110CommunityGroundwater
19Shell Star MartColumbia100Transient non-communityGroundwater
20Scappoose Brew & ThruColumbia100Transient non-communityGroundwater
21Alston Corners-Assembly of GodColumbia100Transient non-communityGroundwater
22Lost Creek Heights Wtr AssocColumbia100CommunityGroundwater
23Deer View CooperativeColumbia90CommunityGroundwater
24Paradise MoorageColumbia90CommunityGroundwater
25Country Villa Mobile EstatesColumbia90CommunityGroundwater
26Deer Island WaterworksColumbia90CommunityGroundwater
27Rainier Congregation of JwColumbia90Transient non-communityGroundwater
28Goble Water AssociationColumbia85CommunityGroundwater
29Columbia Hills HoaColumbia84CommunityGroundwater
30Olympic Forest ProductsColumbia80Non-transient non-communityGroundwater
31Tamarack Mobile Home ParkColumbia80CommunityGroundwater
32Maple Terrace Mobile Home ParkColumbia70CommunityGroundwater
33Prescott, City ofColumbia70CommunityGroundwater
34Mccuddys LandingColumbia70CommunityGroundwater
35Marshland Water AssociationColumbia70CommunitySurface water
36Laurel Ridge MHPColumbia70CommunityGroundwater
37Columbia River Nitrogen, LLCColumbia65Non-transient non-communityGroundwater
38Deer Island Heights WsColumbia60CommunityGroundwater
39Laurelwood Water AssocColumbia50CommunityGroundwater
40Deer Island Village MHP-Fawn LaneColumbia50CommunityGroundwater
41Cedar Tree Mobile Home ParkColumbia50CommunityGroundwater
42Deer Island Village MHPColumbia50CommunityGroundwater
43Valley of the MoonColumbia46Transient non-communityGroundwater
44Berndt Creek Water CorpColumbia45CommunitySurface water
45Columbia River PUDColumbia45Non-transient non-communityGroundwater
46J & M Mobile Home ParkColumbia45CommunityGroundwater
47Dikeside MoorageColumbia45CommunityGroundwater
48Island Community LLCColumbia41Transient non-communityGroundwater
49Swedetown Water AssocColumbia40CommunityGroundwater
50Hogg Heaven MHPColumbia40CommunityGroundwater

All other water systems in Columbia County (7)

The remaining active systems filed under Columbia County, largest first, with the population each reports serving.

Columbia County water systems: frequently asked questions

How many public water systems are in Columbia County, Oregon?

EPA's SDWIS records file 57 active public water systems under Columbia County, Oregon: 37 community systems (65%), 6 non-transient non-community systems (11%) and 14 transient non-community systems (25%).

Who supplies drinking water in Columbia County, OR?

The largest community water systems filed under Columbia County are City of St Helens (13,410 people served), City of Scappoose (8,710 people served) and Mcnulty Water PUD (2,500 people served). Which system serves a particular address depends on its service area, which EPA's SDWIS records do not include; a water bill or the local utility can confirm it.

Does Columbia County's drinking water come from groundwater or surface water?

Of the 57 active public water systems in Columbia County, 84% draw mainly on groundwater and 16% on surface water, counting purchased supplies. The largest system, City of St Helens, uses groundwater under influence of surface water.

Where can I find a water quality report for Columbia County?

Each community water system must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1, covering the previous calendar year. 37 community systems are filed under Columbia County, so the report to look for is the one from the system that supplies your address.

How can I check violations for a water system in Columbia County?

Open the system's profile from the list on this page. Each profile shows the most recent Safe Drinking Water Act violations in EPA's records, with plain-English labels and whether each one is resolved. For current compliance status, EPA ECHO is the primary source.

More Oregon water systems

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, “Public water systems in Columbia County, Oregon”, https://aquacensus.com/water-systems/oregon/columbia (data as of October 1, 2026).