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
🔒 Create a free account to export CSV| # | Water system | County | Population served | Type | Source |
|---|---|---|---|---|---|
| 1 | Mason City Water Department | Cerro Gordo | 27,338 | Community | Groundwater |
| 2 | Clear Lake Water Department | Cerro Gordo | 7,687 | Community | Groundwater |
| 3 | Rockwell Water Supply | Cerro Gordo | 1,071 | Community | Groundwater |
| 4 | Ventura Water Works | Cerro Gordo | 716 | Community | Groundwater |
| 5 | Thornton Water Supply | Cerro Gordo | 400 | Community | Groundwater |
| 6 | Plymouth Water Supply | Cerro Gordo | 378 | Community | Groundwater |
| 7 | Bell Harbor | Cerro Gordo | 352 | Transient non-community | Groundwater |
| 8 | Meservey Water Supply | Cerro Gordo | 222 | Community | Groundwater |
| 9 | P.M. Park Trustees-East | Cerro Gordo | 152 | Transient non-community | Groundwater |
| 10 | Swaledale Water Supply | Cerro Gordo | 144 | Community | Groundwater |
| 11 | Clear Lake Baptist Church | Cerro Gordo | 140 | Transient non-community | Groundwater |
| 12 | Heidelberg Materials Us Cement LLC | Cerro Gordo | 130 | Non-transient non-community | Groundwater |
| 13 | Luckys Last Resort Campground | Cerro Gordo | 105 | Transient non-community | Groundwater |
| 14 | Lime Creek Conservation Area | Cerro Gordo | 81 | Transient non-community | Groundwater |
| 15 | Rock Falls Lounge | Cerro Gordo | 80 | Transient non-community | Groundwater |
| 16 | Camp at the Woods | Cerro Gordo | 69 | Transient non-community | Groundwater |
| 17 | Clear Water Campground | Cerro Gordo | 68 | Transient non-community | Groundwater |
| 18 | Oakwood Park Water Association | Cerro Gordo | 66 | Transient non-community | Groundwater |
| 19 | Oak Hills Par 30 Golf Course | Cerro Gordo | 60 | Transient non-community | Groundwater |
| 20 | Oakwood Rv Park | Cerro Gordo | 60 | Transient non-community | Groundwater |
| 21 | Pine Creek Golf Course | Cerro Gordo | 55 | Transient non-community | Groundwater |
| 22 | Twin Oak Camp Ground | Cerro Gordo | 54 | Transient non-community | Groundwater |
| 23 | Buffalo Run Golf Club | Cerro Gordo | 51 | Transient non-community | Groundwater |
| 24 | Long Beach Mobile Park | Cerro Gordo | 50 | Community | Groundwater |
| 25 | Ziegler Cat (Mason City) | Cerro Gordo | 49 | Transient non-community | Groundwater |
| 26 | Grandview Circle Water Association | Cerro Gordo | 48 | Transient non-community | Groundwater |
| 27 | Four Oaks (Mason City) | Cerro Gordo | 38 | Non-transient non-community | Groundwater |
| 28 | Mason City Red Power Inc. | Cerro Gordo | 38 | Transient non-community | Groundwater |
| 29 | Lakeshore Water Association | Cerro Gordo | 38 | Transient non-community | Groundwater |
| 30 | Van Wall Equipment (Mason City) | Cerro Gordo | 34 | Transient non-community | Groundwater |
| 31 | Wilkinson Pioneer Park | Cerro Gordo | 27 | Transient non-community | Groundwater |
| 32 | Linn Grove Park | Cerro Gordo | 27 | Transient non-community | Groundwater |
| 33 | Oakridge Homeowners Association | Cerro Gordo | 26 | Transient non-community | Groundwater |
| 34 | Camp Tanglefoot | Cerro Gordo | 25 | Transient non-community | Groundwater |
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.
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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, “Public water systems in Cerro Gordo County, Iowa”, https://aquacensus.com/water-systems/iowa/cerro-gordo (data as of October 1, 2026).