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Cerro Gordo County, Iowa — public water systems

At a glance

34 active public water systems are filed under Cerro Gordo County, Iowa in EPA's SDWIS records, together reporting 39,879 people served. The largest is Mason City Water Department, which reports serving 27,338 people. 9 are community water systems serving people where they live; the other 25 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

34

Population served

39.9K

Community systems

9

Groundwater share

100%

How does Cerro Gordo County compare with other Iowa counties?

Cerro Gordo County has the 11th-most active public water systems among the 114 counties listed for active Iowa systems in EPA records; among the 96 with 3 or more systems, the median has 14. Its systems report 39,879 people served in total, the 15th-largest county figure in the state and 1.3% of the statewide total. The average system here reports serving 1,173 people, about 32% below the Iowa average of 1,718. 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 Cerro Gordo County's drinking water come from?

By primary water source, Cerro Gordo County's active systems draw on groundwater (34, 100%). Overall, all rely mainly on groundwater (including purchased groundwater) and none on surface water, compared with 92% and 7.8% across Iowa. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, Mason City Water Department, draws primarily on groundwater.

What kinds of water systems operate in Cerro Gordo County?

Cerro Gordo County's active systems break down as 9 community systems (26%), 2 non-transient non-community systems (5.9%) and 23 transient non-community systems (68%). 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 (65%), local government (32%) and state government (2.9%).

Water systems in Cerro Gordo County

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Active public water systems in Cerro Gordo County, Iowa
#Water systemCountyPopulation servedTypeSource
1Mason City Water DepartmentCerro Gordo27,338CommunityGroundwater
2Clear Lake Water DepartmentCerro Gordo7,687CommunityGroundwater
3Rockwell Water SupplyCerro Gordo1,071CommunityGroundwater
4Ventura Water WorksCerro Gordo716CommunityGroundwater
5Thornton Water SupplyCerro Gordo400CommunityGroundwater
6Plymouth Water SupplyCerro Gordo378CommunityGroundwater
7Bell HarborCerro Gordo352Transient non-communityGroundwater
8Meservey Water SupplyCerro Gordo222CommunityGroundwater
9P.M. Park Trustees-EastCerro Gordo152Transient non-communityGroundwater
10Swaledale Water SupplyCerro Gordo144CommunityGroundwater
11Clear Lake Baptist ChurchCerro Gordo140Transient non-communityGroundwater
12Heidelberg Materials Us Cement LLCCerro Gordo130Non-transient non-communityGroundwater
13Luckys Last Resort CampgroundCerro Gordo105Transient non-communityGroundwater
14Lime Creek Conservation AreaCerro Gordo81Transient non-communityGroundwater
15Rock Falls LoungeCerro Gordo80Transient non-communityGroundwater
16Camp at the WoodsCerro Gordo69Transient non-communityGroundwater
17Clear Water CampgroundCerro Gordo68Transient non-communityGroundwater
18Oakwood Park Water AssociationCerro Gordo66Transient non-communityGroundwater
19Oak Hills Par 30 Golf CourseCerro Gordo60Transient non-communityGroundwater
20Oakwood Rv ParkCerro Gordo60Transient non-communityGroundwater
21Pine Creek Golf CourseCerro Gordo55Transient non-communityGroundwater
22Twin Oak Camp GroundCerro Gordo54Transient non-communityGroundwater
23Buffalo Run Golf ClubCerro Gordo51Transient non-communityGroundwater
24Long Beach Mobile ParkCerro Gordo50CommunityGroundwater
25Ziegler Cat (Mason City)Cerro Gordo49Transient non-communityGroundwater
26Grandview Circle Water AssociationCerro Gordo48Transient non-communityGroundwater
27Four Oaks (Mason City)Cerro Gordo38Non-transient non-communityGroundwater
28Mason City Red Power Inc.Cerro Gordo38Transient non-communityGroundwater
29Lakeshore Water AssociationCerro Gordo38Transient non-communityGroundwater
30Van Wall Equipment (Mason City)Cerro Gordo34Transient non-communityGroundwater
31Wilkinson Pioneer ParkCerro Gordo27Transient non-communityGroundwater
32Linn Grove ParkCerro Gordo27Transient non-communityGroundwater
33Oakridge Homeowners AssociationCerro Gordo26Transient non-communityGroundwater
34Camp TanglefootCerro Gordo25Transient non-communityGroundwater

Cerro Gordo County water systems: frequently asked questions

How many public water systems are in Cerro Gordo County, Iowa?

EPA's SDWIS records file 34 active public water systems under Cerro Gordo County, Iowa: 9 community systems (26%), 2 non-transient non-community systems (5.9%) and 23 transient non-community systems (68%).

Who supplies drinking water in Cerro Gordo County, IA?

The largest community water systems filed under Cerro Gordo County are Mason City Water Department (27,338 people served), Clear Lake Water Department (7,687 people served) and Rockwell Water Supply (1,071 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 Cerro Gordo County's drinking water come from groundwater or surface water?

Of the 34 active public water systems in Cerro Gordo County, all draw mainly on groundwater and none on surface water, counting purchased supplies. The largest system, Mason City Water Department, uses groundwater.

Where can I find a water quality report for Cerro Gordo 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. 9 community systems are filed under Cerro Gordo 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 Cerro Gordo 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 Iowa 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 Cerro Gordo County, Iowa”, https://aquacensus.com/water-systems/iowa/cerro-gordo (data as of October 1, 2026).