MASON, OH · Warren County

MASON, CITY OF Water System

Inactive system

This water system is marked inactive in EPA’s federal records as of November 29, 2004. It is no longer an operating public water system under this PWSID, and no compliance deadlines — including the 2027 Consumer Confidence Report rule — apply to it.

If you are a resident looking for your current water provider, see water systems in Warren County, OH.

Data sourced from the EPA ECHO database (SDWA bulk download), last refreshed August 1, 2026. This is a record-keeping and public-information tool — it does not replace Ohio’s official records. Always confirm current status with Ohio before making decisions based on this information.

System facts

System ID (PWSID): OH8300812
System type: Community Water System
Population served: 11,000
Service connections: 3,637
Ownership: local government
Water source: groundwater (wells)

MASON, CITY OF is one of 180 community water systems in Ohio in the 10,001 to 100,000 people size category, formerly serving 11,000 people from groundwater.

EPA's federal records list this system as inactive in 2004; the record below is historical.

As of August 1, 2026, its federal record holds 24 entries between 1993 and 1999, all of which EPA lists as closed. Nothing has been added since 1999.

Of the 24, 23 are monitoring and reporting requirements — the category that accounts for about four in five of all violations in EPA's national dataset — rather than findings about the water itself. The record involves volatile organic chemicals, the Total Coliform Rules, and inorganic chemicals.

Violation history

Monitoring, Regular
—
cis-1,2-Dichloroethylene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
o-Dichlorobenzene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
p-Dichlorobenzene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
1,1,2-Trichloroethane
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
Xylenes, Total
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
1,1,1-Trichloroethane
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
1,2-Dichloropropane
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
CHLOROBENZENE
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
Benzene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
1,2,4-Trichlorobenzene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
DICHLOROMETHANE
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
Vinyl chloride
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
1,2-Dichloroethane
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
Tetrachloroethylene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
Ethylbenzene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
1,1-Dichloroethylene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
Carbon tetrachloride
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
Trichloroethylene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
Toluene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
Styrene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
trans-1,2-Dichloroethylene
July 1, 1999 – September 30, 1999
Resolved
Monitoring, Regular
—
Nitrate
July 1, 1996 – December 31, 1996
Resolved
Monitoring, Repeat Major (TCR)
—
Coliform (TCR)
March 1, 1993 – March 31, 1993
Archived
Maximum Contaminant Level Violation, Acute (TCR)
Health-based
Coliform (TCR)
March 1, 1993 – March 31, 1993
Archived

Resolved addressed and confirmed by the stateArchived closed in EPA's records (typically due to age or a data correction)

Period	Violation	Contaminant / rule	Health-based	Status
July 1, 1999 – September 30, 1999	Monitoring, Regular	cis-1,2-Dichloroethylene	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	o-Dichlorobenzene	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	p-Dichlorobenzene	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	1,1,2-Trichloroethane	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	Xylenes, Total	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	1,1,1-Trichloroethane	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	1,2-Dichloropropane	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	CHLOROBENZENE	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	Benzene	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	1,2,4-Trichlorobenzene	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	DICHLOROMETHANE	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	Vinyl chloride	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	1,2-Dichloroethane	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	Tetrachloroethylene	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	Ethylbenzene	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	1,1-Dichloroethylene	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	Carbon tetrachloride	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	Trichloroethylene	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	Toluene	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	Styrene	—	Resolved
July 1, 1999 – September 30, 1999	Monitoring, Regular	trans-1,2-Dichloroethylene	—	Resolved
July 1, 1996 – December 31, 1996	Monitoring, Regular	Nitrate	—	Resolved
March 1, 1993 – March 31, 1993	Monitoring, Repeat Major (TCR)	Coliform (TCR)	—	Archived
March 1, 1993 – March 31, 1993	Maximum Contaminant Level Violation, Acute (TCR)	Coliform (TCR)	Health-based	Archived

Resolved addressed and confirmed by the stateArchived closed in EPA's records (typically due to age or a data correction)

Enforcement actions

February 8, 2000State Violation/Reminder Notice36 linked violations
January 17, 1985State Formal Notice of Violation issuedgeneral compliance action — not tied to a specific violation on record

Last known contact on file (system is inactive)

Not on record

513-229-8500

MASON, OH 45040