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Lyon County, Iowa — public water systems

At a glance

12 active public water systems are filed under Lyon County, Iowa in EPA's SDWIS records, together reporting 12,196 people served. The largest is Rock Rapids Municipal Water Works, which reports serving 2,611 people. All 12 are community water systems serving people where they live.

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

Active systems

12

Population served

12.2K

Community systems

12

Groundwater share

100%

How does Lyon County compare with other Iowa counties?

Lyon County has the 61st-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 12,196 people served in total, the 55th-largest county figure in the state and 0.4% of the statewide total. The average system here reports serving 1,016 people, about 41% 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 Lyon County's drinking water come from?

By primary water source, Lyon County's active systems draw on purchased groundwater (7, 58%) and groundwater (5, 42%). Overall, all rely mainly on groundwater (including purchased groundwater) and none on surface water, compared with 92% and 7.8% across Iowa. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own. The county's largest system, Rock Rapids Municipal Water Works, draws primarily on groundwater.

What kinds of water systems operate in Lyon County?

Lyon County's active systems break down as 12 community systems (100%). 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. EPA lists their owner types as local government (67%) and private (33%).

Water systems in Lyon County

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Active public water systems in Lyon County, Iowa
#Water systemCountyPopulation servedTypeSource
1Rock Rapids Municipal Water WorksLyon2,611CommunityGroundwater
2Lyon-Sioux Rws-DoonLyon1,765CommunityGroundwater
3Lyon-Sioux Rws-Big SiouxLyon1,530CommunityGroundwater
4Lyon-Sioux Rws-Rock RapidsLyon1,187CommunityPurchased groundwater
5George Water SupplyLyon1,082CommunityGroundwater
6Inwood Water SupplyLyon928CommunityPurchased groundwater
7Larchwood Water SupplyLyon926CommunityPurchased groundwater
8Doon Water SupplyLyon619CommunityPurchased groundwater
9Lyon-Sioux Rws-BoydenLyon605CommunityGroundwater
10Little Rock Water SupplyLyon441CommunityPurchased groundwater
11Lester Water SupplyLyon296CommunityPurchased groundwater
12Alvord Municipal Water SupplyLyon206CommunityPurchased groundwater

Lyon County water systems: frequently asked questions

How many public water systems are in Lyon County, Iowa?

EPA's SDWIS records file 12 active public water systems under Lyon County, Iowa: 12 community systems (100%).

Who supplies drinking water in Lyon County, IA?

The largest community water systems filed under Lyon County are Rock Rapids Municipal Water Works (2,611 people served), Lyon-Sioux Rws-Doon (1,765 people served) and Lyon-Sioux Rws-Big Sioux (1,530 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 Lyon County's drinking water come from groundwater or surface water?

Of the 12 active public water systems in Lyon County, all draw mainly on groundwater and none on surface water, counting purchased supplies. The largest system, Rock Rapids Municipal Water Works, uses groundwater.

Where can I find a water quality report for Lyon 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. 12 community systems are filed under Lyon 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 Lyon 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 Lyon County, Iowa”, https://aquacensus.com/water-systems/iowa/lyon (data as of October 1, 2026).