Public water system · OH0903912
ActiveSouthwest Regional Water District
At a glance
Southwest Regional Water District (PWSID OH0903912) is an active community water system in Butler County, Ohio. It reports serving 42,856 people through 15,875 service connections. Its primary water source is groundwater, and EPA lists it as under public/private ownership. EPA's Safe Drinking Water Act records list no violations for this system.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
42,856
Service connections
15,875
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Southwest Regional Water District compare with other water systems in Butler County?
By EPA's size categories, Southwest Regional Water District is a large system (10,001 to 100,000 people). Butler County has 20 active public water systems, and Southwest Regional Water District is the 5th-largest of them by population served. Its population served is about 126% above the county average of 18,928 people per system, and accounts for 11% of the 378,564 people reported by systems filed under the county. Across Ohio, the 3,854 active systems average 2,767 people each. Nationally, the average active community water system reports serving 6,703 people, so Southwest Regional Water District is about 6.4 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. Ohio has 1,028 active community water systems, 27% of the state's 3,854 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 3,446 Ohio systems (89%) list groundwater as their primary source.
Who owns and regulates Southwest Regional Water District?
EPA lists Southwest Regional Water District as under public/private ownership. The OH state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 1 of the 20 active systems in Butler County (5%) are also under public/private ownership.
Does Southwest Regional Water District have drinking water violations?
No SDWA violations on record.
EPA's SDWA violation and enforcement data (via EPA ECHO, updated quarterly) lists no violations for Southwest Regional Water District. For the latest compliance status, check EPA ECHO for current compliance history.
Southwest Regional Water District: frequently asked questions
Who runs Southwest Regional Water District?
Southwest Regional Water District (PWSID OH0903912) is a community water system under public/private ownership. It is regulated by the OH state drinking water program.
How many people does Southwest Regional Water District serve?
Southwest Regional Water District reports serving 42,856 people through 15,875 service connections in Butler County, Ohio.
Where does Southwest Regional Water District 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 Southwest Regional Water District have any drinking water violations?
EPA's Safe Drinking Water Act records list no violations for this system.
Is Southwest Regional Water District'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 Safe Drinking Water Act records list no violations for this system. For current results, consult the system's annual water quality report, EPA ECHO, or the OH state drinking water program.
Where can I find Southwest Regional Water District's water quality report?
As a community water system, Southwest Regional Water District 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 Butler County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Butler Co. Water District 2 Pws | Butler | 116,572 | Community | Purchased surface water |
| Hamilton Public Water System | Butler | 62,447 | Community | Groundwater |
| Middletown City Pws | Butler | 51,229 | Community | Groundwater |
| Fairfield City Pws | Butler | 44,907 | Community | Groundwater |
| Oxford City Pws | Butler | 24,000 | Community | Groundwater |
| Monroe City Pws | Butler | 15,600 | Community | Purchased surface water |
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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, “Southwest Regional Water District, PWSID OH0903912, Ohio”, https://aquacensus.com/water-systems/ohio/southwest-regional-water-district-oh0903912 (data as of October 1, 2026).