Note: For certified and registered electric suppliers, click Electric Choice/Plug In Illinois®.
- Apple Canyon Utility Company
- Aqua Illinois, Inc.
- Bahl Water Corporation
- Camelot Utilities, Inc.
- Cedar Water Company, Inc.
- Charmar Water Company
- Cherry Hill Water Company
- Clarendon Water Company
- Crystal Clear Water Co.
- David M. Smith,
d/b/a Colonial Meadows Water Company
- Del-Mar Water Company
- Eastwood Manor Water Company
- Ferson Creek Utilities Company
- Galena Territory Utilities, Inc.
- Great Northern Utilities, Inc.
- Harbor Ridge Utilities, Inc.
- Holiday Hills Utilities, Inc.
- Illinois-American Water Company
- Killarney Water Co.
- Lake Holiday Utilities Corporation
- Lake Marian Water Corporation
- Lake Wildwood Utilities Corporation
- McHenry Shores Water Company
- Nordic Park Water and Sewerage Disposal Co., Inc.
- Northern Hills Water and Sewer Company
- Nunda Utility Co.
- Powers Water Company, Inc.
- Rockvale Corporation
- Rockwell Utilities, LLC
- Silvis Heights Water Corporation
- Sundale Utilities, Inc.
- Valentine Water Service, Inc.
- Walk-Up Woods Water Company
- Westlake Utilities, Inc.
- Whispering Hills Water Co.
- Wildwood Water Service Company
- Woodlawn Utilities Corporation