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DeKalb County, Illinois — public water systems

At a glance

43 active public water systems are filed under DeKalb County, Illinois in EPA's SDWIS records, together reporting 95,450 people served. The largest is Dekalb, which reports serving 40,290 people. 20 are community water systems serving people where they live; the other 23 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

43

Population served

95.5K

Community systems

20

Groundwater share

100%

How does DeKalb County compare with other Illinois counties?

DeKalb County has the 26th-most active public water systems among the 149 counties listed for active Illinois systems in EPA records; among the 104 with 3 or more systems, the median has 18. Its systems report 95,450 people served in total, the 18th-largest county figure in the state and 0.8% of the statewide total. The average system here reports serving 2,220 people, about 31% below the Illinois average of 3,204. 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 DeKalb County's drinking water come from?

By primary water source, DeKalb County's active systems draw on groundwater (38, 88%) and purchased groundwater (5, 12%). Overall, all rely mainly on groundwater (including purchased groundwater) and none on surface water, compared with 82% and 18% across Illinois. Groundwater means the system draws its water from wells or springs fed by underground aquifers. The county's largest system, Dekalb, draws primarily on groundwater.

What kinds of water systems operate in DeKalb County?

DeKalb County's active systems break down as 20 community systems (47%), 2 non-transient non-community systems (4.7%) and 21 transient non-community systems (49%). 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 (58%), local government (30%), public/private partnership (9.3%) and state government (2.3%).

Water systems in DeKalb County

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Active public water systems in DeKalb County, Illinois
#Water systemCountyPopulation servedTypeSource
1DekalbDeKalb40,290CommunityGroundwater
2SycamoreDeKalb18,500CommunityGroundwater
3SandwichDeKalb7,156CommunityGroundwater
4Northern Illinois University-DekalbDeKalb6,500CommunityPurchased groundwater
5GenoaDeKalb5,298CommunityGroundwater
6CortlandDeKalb4,398CommunityGroundwater
7HinckleyDeKalb2,006CommunityGroundwater
8KirklandDeKalb2,000CommunityGroundwater
9SomonaukDeKalb1,860CommunityGroundwater
10WatermanDeKalb1,497CommunityGroundwater
11KingstonDeKalb1,160CommunityGroundwater
12MaltaDeKalb1,143CommunityGroundwater
13Suburban Apartments (De Kalb Univ Dvl)DeKalb1,050CommunityGroundwater
14ShabbonaDeKalb913CommunityGroundwater
15Cortland Corners MHPDeKalb205CommunityGroundwater
16Kishwaukee CollegeDeKalb200Non-transient non-communityGroundwater
17Buck Lake Estates SubdivisionDeKalb150CommunityGroundwater
18Triangle Manufactured Home CommunityDeKalb124CommunityPurchased groundwater
19Valley View Subdivision (Dekalb)DeKalb120CommunityGroundwater
20Sycamore Park District - Soccer FieldsDeKalb100Transient non-communityGroundwater
21Sandwich Estates MHPDeKalb90CommunityPurchased groundwater
22Sycamore Rv ResortDeKalb75Transient non-communityGroundwater
23Indian Oaks Country ClubDeKalb75Transient non-communityGroundwater
24Bayer Co - Waterman Research FacilityDeKalb50Non-transient non-communityGroundwater
25Walcamp Lutheran Retreat-Bathhouse NorthDeKalb35Transient non-communityGroundwater
26Donny Brook Estates SubdivisionDeKalb30CommunityGroundwater
27Meijer 313DeKalb25Transient non-communityPurchased groundwater
28Harvest Chapel Assembly of GodDeKalb25Transient non-communityGroundwater
29Franks Freshway Market - GenoaDeKalb25Transient non-communityPurchased groundwater
30Walcamp Lutheran Retreat-Bathhouse SouthDeKalb25Transient non-communityGroundwater
31Walcamp Lutheran Retreat-KitchenDeKalb25Transient non-communityGroundwater
32Walcamp Lutheran Retreat-PavillionDeKalb25Transient non-communityGroundwater
33North Grove School AssociationDeKalb25Transient non-communityGroundwater
34Mayfield Congregational ChurchDeKalb25Transient non-communityGroundwater
35Gum Farm Hunt ClubDeKalb25Transient non-communityGroundwater
36Dekalb County Animal LeagueDeKalb25Transient non-communityGroundwater
37Waterman Winery and Vineyards Inc.DeKalb25Transient non-communityGroundwater
38Evangelical Lutheran ChurchDeKalb25Transient non-communityGroundwater
39Paw Paw Township ParkDeKalb25Transient non-communityGroundwater
40Trinity Lutheran Church GenoaDeKalb25Transient non-communityGroundwater
41Sandwich Sportsmans ClubDeKalb25Transient non-communityGroundwater
42Calvary Lutheran ChurchDeKalb25Transient non-communityGroundwater
43Jonamac OrchardDeKalb25Transient non-communityGroundwater

DeKalb County water systems: frequently asked questions

How many public water systems are in DeKalb County, Illinois?

EPA's SDWIS records file 43 active public water systems under DeKalb County, Illinois: 20 community systems (47%), 2 non-transient non-community systems (4.7%) and 21 transient non-community systems (49%).

Who supplies drinking water in DeKalb County, IL?

The largest community water systems filed under DeKalb County are Dekalb (40,290 people served), Sycamore (18,500 people served) and Sandwich (7,156 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 DeKalb County's drinking water come from groundwater or surface water?

Of the 43 active public water systems in DeKalb County, all draw mainly on groundwater and none on surface water, counting purchased supplies. The largest system, Dekalb, uses groundwater.

Where can I find a water quality report for DeKalb 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. 20 community systems are filed under DeKalb 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 DeKalb 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 Illinois 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 DeKalb County, Illinois”, https://aquacensus.com/water-systems/illinois/dekalb (data as of October 1, 2026).