Tapcensus

Illinois

McHenry County drinking water quality

307 active public water systems serve 271,908 people in McHenry County. 234 are compliant, 73 had at least one EPA violation in the past three years, 2 are designated serious violators, and 3 carry a health flag.

Active systems 307 32 community systems
People served 272K by public water systems
Systems with violations 73 24% of active systems, past 3 years
Serious violators 2 3 systems carry a health flag

Needs attention

Huntley IL1110350 · Huntley · Community water system · Serves 28,495 1 rule violated in the past three years
Mindhaven Academy IL3049809 · Non-Transient non-community system · Serves 100 7 rules violated in the past three years. Unresolved: 1,1,1-Trichloroethane, 1,1,2-Trichloroethane, 1,1-Dichloroethylene, 1,2,4-Trichlorobenzene, 1,2-Dibromo-3-Chloropropane (DBCP), 1,2-Dichloroethane, 1,2-Dichloropropane, 2,4,5-TP (Silvex), 2,4-D, Alachlor (Lasso), Atrazine, BHC-Gamma (Lindane), Benzene, Benzo(a)pyrene, Carbofuran, Carbon Tetrachloride, Chlordane, Chlorobenzene, Dalapon, Di(2-ethylhexyl) Adipate, Di(2-ethylhexyl) Phthalate, Dichloromethane (Methylene Chloride), Dinoseb, Diquat, Endothall, Endrin, Ethylbenzene, Ethylene Dibromide (EDB), Glyphosate, Heptachlor, Heptachlor Epoxide, Hexachlorobenzene, Hexachlorocyclopentadiene, Lead and Copper Rule (LCR), Methoxychlor, Oxamyl (Vydate), Pentachlorophenol, Picloram, Polychlorinated Biphenyls (PCBs), Simazine, Styrene, Tetrachloroethylene (PCE), Toluene, Toxaphene, Trichloroethylene (TCE), Vinyl Chloride, Xylenes, Total, cis-1,2-Dichloroethylene, o-Dichlorobenzene, p-Dichlorobenzene, and trans-1,2-Dichloroethylene.
Leica Biosystems IL3131045 · Non-Transient non-community system · Serves 100 2 rules violated in the past three years. Unresolved: Revised Total Coliform Rule (RTCR).
Marengo Ridge (16162) IL3016162 · Transient non-community system · Serves 50 3 rules violated in the past three years. Unresolved: Groundwater Rule (GWR).
Lehman's Lakeside Resort Rental House IL3070813 · Transient non-community system · Serves 45 1 rule violated in the past three years. Unresolved: Revised Total Coliform Rule (RTCR).

Community water systems

32 systems, largest first
SystemServesStatusRules violated, 3 yrUnresolved
Crystal Lake
Crystal Lake 		40,661 1 0
Algonquin
Algonquin 		30,700 0 0
Lake in the Hills
Lake In The Hills 		28,661 1 0
Huntley
Huntley 		28,495 1 0
Woodstock
Woodstock 		25,630 3 0
McHenry
Mchenry 		22,335 2 0
Cary
Cary 		17,826 1 1
Harvard
Harvard 		9,469 0 0
IL American-Whispering Hills
 8,300 4 0
Marengo
Marengo 		7,572 0 0
Fox River Grove
Fox River Grove 		4,702 0 0
Lakewood
Lakewood 		4,267 2 1
Wonder Lake
 3,870 2 0
Richmond
Richmond 		2,089 0 0
Wonder Lake (niu)
 1,950 2 0
Aqua Illinois-McHenry Shores
 1,862 0 0
Hebron
Hebron 		1,368 2 1
IL American-Killarney
 1,232 0 0
Johnsburg No.2
 1,124 3 0
Oakbrook Estates MHP
 1,012 1 0
IL American-Holiday Hills
Holiday Hills 		868 0 0
Aqua Illinois-Crystal Clear Water Co.
 855 1 0
IL American-Walk UP Woods
 775 3 0
Aqua Illinois-Eastwood Manor
 728 2 2
IL American-Terra Cotta
 681 0 0
Union
Union 		594 2 1
Aqua Illinois-Nunda
 485 0 0
Johnsburg 1
 174 4 0
Royal Oaks MHP
 170 1 1
Prairie Ridge Association
 148 0 0
Harbor Lites-Pistakee Fshg CL
 132 2 2
Valley HI Nursing Home
 125 1 1
Non-community systems (275: schools, campgrounds, workplaces, restaurants)

These systems serve places people visit rather than homes.

SystemServesStatusRules violated, 3 yrUnresolved
Prairie Grove School
 1,050 2 0
Snap on Tools
 700 7 0
Northwestern Medicine McHenry Hospital
 600 0 0
Johnsburg JR High School
 575 2 0
Lippold Park Con Softball Boncosky
 500 0 0
Spring Grove Elementary School
 500 6 0
ST Peters Church
 500 0 0
Greenwood School
 400 1 0
Illinois Turner Camp Pool
 400 0 0
Resurrection Church
 350 0 0
Fellowship of Faith Lutheran Church
 330 0 0
Cafe 31 North
 300 0 0
Christ the King Church
 300 0 0
Northwestern Medicine Woodstock Hospital
 300 2 1
Valley View School
 300 5 0
Scot Forge
 253 3 1
Crystal Creek Farm
 251 0 0
Crystal Lake Park D/w Herrick
 250 0 0
Shiloh Church
 250 0 0
Riley Community School
 220 5 0
Riverside Pub
 220 0 0
Kingdom Hall of Jehovahs Witnesses
 219 0 0
Banquetes Y Cocina
 200 0 0
Big Foot Inn
 200 0 0
Bostik, INC
 200 1 0
Crystal Lake Montessori
 200 0 0
Illinois Railway Museum North Well
 200 0 0
Itw Medical
 200 3 0
Lehman's Lakeside Resort Rental House
 200 2 1
Mary Ann Beebe Ctr/activity Ctr (18226)
 200 1 1
Orchard Fun, LLC (cider & Bakery)
 200 0 0
Pioneer Center for Human Services
 200 0 0
Ringwood Primary Center
 170 1 0
Boone Creek Golf Club
 150 0 0
Chicago NW KOA Kampground
 150 0 0
Illinois Railway Museum South Well
 150 0 0
Johnsburg Community Club
 150 0 0
Moraine Hills SP Northern Woods
 150 0 0
ST John Baptist
 150 2 1
First Presbyterian Church
 130 0 0
Cullom Knoll
 125 0 0
Longhorn Equity Partners LLC
 125 0 0
The Breakers
 125 0 0
State Bank of the Lakes
 111 0 0
Alden Quick Mart
 100 0 0
Cary Country Clubhse/main Dept
 100 0 0
Chapel Hill Country Club
 100 2 0
Chicago NW KOA
 100 0 0
Christ Covenant Presbyterian Church
 100 0 0
Church of Latter Day Saints
 100 0 0
Crandalls
 100 0 0
Crystal Lake 31
 100 0 0
Crystal Lake Christian Church
 100 0 0
Crystal Woods Golf/jay Craig
 100 0 0
Difranco Brothers LLC
 100 0 0
Dilars Cafe
 100 0 0
Evangelical Free Church
 100 0 0
Grace Lutheran/sue Fosdal
 100 2 0
Grandma's Mexican Kitchen
 100 0 0
Illinois Turner Camp-Rathskeller
 100 0 0
Leica Biosystems
 100 2 1
Lord and Savior Lutheran
 100 5 2
Maranatha Assembly of God
 100 0 0
Marengo Ridge Golf Club
 100 0 0
MC Henry Outdoor Theatre
 100 1 1
MC Henry Recreation
 100 0 0
McHenry Athletic Complex
 100 0 0
Mindhaven Academy
 100 7 1
Moraine Hills ST Park Lake Defiance
 100 1 0
Natures Scholars Daycare
 100 1 1
Oak Grove Golf Course
 100 0 0
Prairie Isle Golf Club
 100 0 0
Ridgefield-Crystal Lake Presbyterian Chu
 100 0 0
River Road Shell
 100 0 0
TC Industries
 100 3 0
Wonder Lake Bible Church
 100 0 0
Woodstock Country Club
 100 0 0
I AM I Can Preschool & Daycare
 98 0 0
Alden United Methodist Church
 80 0 0
Blackstone Golf Club Halfway House
 80 0 0
Joyful Harvest Church
 80 0 0
Royal Oaks Country Farm
 80 1 1
Broken Oar
 75 1 0
Busy Bee Restaurant
 75 0 0
Chalet Chateau
 75 0 0
Crystal Lake P D Skateboard Park
 75 0 0
Harvard Sportsman Club
 75 0 0
Kcs Cabin
 75 1 0
Lippold Park Crystal Lake Park Dist
 75 0 0
Pork King
 75 1 0
River Cafe
 75 0 0
Snuggery
 75 0 0
Spring Beach Inn
 75 0 0
Whiskey Bungalow
 75 0 0
Wonder Lake BP
 75 0 0
Sammy's Bar & Gaming
 74 0 0
Woodstock Dist 200 Trans Dept
 70 0 0
Ringers Landscaping Services Inc.
 65 3 1
American AD Bag
 60 2 1
Nikos Grill & Pub
 55 0 0
All 275 in the systems table
Inactive systems (990, no longer operating or reporting)

Kept for the record and excluded from the county totals above. Browse inactive systems.

About this data

Totals cover active systems. Systems serving more than one county are counted in each county. EPA counts the rules a system was in violation of, not the individual violations; one rule can carry several.

Source: the U.S. EPA's Enforcement and Compliance History Online system (ECHO), which publishes the federal Safe Drinking Water Information System. EPA's terms and values are shown as published. The Illinois records are from EPA's data refresh of Oct 7, 2026; EPA refreshes this data quarterly, and states report to EPA with a lag of three to six months, so the newest violations may not appear yet. Retrieved from ECHO on Oct 11, 2026.