Interim Enhanced Surface Water Treatment Rule violations in Colorado
170 active public water systems in Colorado had a Interim Enhanced Surface Water Treatment Rule violation in the past three years, 30 of them in the latest quarter of EPA's data. What Interim Enhanced Surface Water Treatment Rule is and why it matters.
Systems with a Interim Enhanced Surface Water Treatment Rule violation
Latest quarter first, then largest first| System | Serves | Status | Rules violated, 3 yr | Unresolved |
|---|---|---|---|---|
|
Grand Junction City of Mesa County |
26,000 | 2 | 0 | |
|
Gypsum Town of Eagle County |
15,272 | 2 | 0 | |
|
Grand County Water NO 1 Grand County |
5,400 | 11 | 0 | |
|
Perry Park Wsd Douglas County |
3,890 | 3 | 0 | |
|
Walsenburg City of Huerfano County |
3,230 | 6 | 2 | |
|
Colorado City MD Pueblo County |
2,755 | 8 | 4 | |
|
Fowler Town of Otero County |
1,169 | 4 | 1 | |
|
Highland Lakes WD Teller County |
875 | 7 | 2 | |
|
San Lazaro Mfctd Housing Community Boulder County |
844 | 5 | 0 | |
|
Camp Alexander Boy Scouts Park County |
785 | 3 | 0 | |
|
Riverview CG Larimer County |
450 | 3 | 1 | |
|
Stagecoach State Park Routt County |
405 | 4 | 0 | |
|
Sylvan Lake State Park Eagle County |
255 | 4 | 1 | |
|
Phippsburg Town of Routt County |
200 | 5 | 0 | |
|
Ophir Town of San Miguel County |
193 | 9 | 1 | |
|
Redstone Wsd Pitkin County |
180 | 3 | 0 | |
|
Sans Souci Cooperative Boulder County |
150 | 8 | 2 | |
|
Pine Creek Cookhouse Pitkin County |
144 | 3 | 0 | |
|
Ponderosa Lodge INC Chaffee County |
125 | 4 | 1 | |
|
Livermore WS Larimer County |
99 | 3 | 1 | |
|
Eden Valley Institute Larimer County |
91 | 11 | 1 | |
|
Steamboat Mountain School Routt County |
83 | 8 | 0 | |
|
Crystola Roadhouse Teller County |
80 | 6 | 2 | |
|
Trappers Lake Lodge Garfield County |
75 | 5 | 1 | |
|
Drowsy Water Ranch Grand County |
71 | 3 | 0 | |
|
Blue Leaf School LLC Boulder County |
65 | 5 | 1 | |
|
Freemons Guest Ranch Mineral County |
65 | 3 | 1 | |
|
Rifle Falls State Park Garfield County |
64 | 4 | 3 | |
|
Highlands Camp and Retreat Center Boulder County |
63 | 5 | 2 | |
|
Mustang Water Authority Montrose County |
0 | 7 | 1 | |
|
Denver Water Board Denver County |
1,287,000 | 3 | 0 | |
|
Thornton City of Adams County |
226,465 | 2 | 0 | |
|
FT Collins City of Larimer County |
179,901 | 4 | 0 | |
|
Arvada City of Jefferson County |
171,610 | 2 | 0 | |
|
Boulder City of Boulder County |
166,080 | 1 | 0 | |
|
Pueblo West MD Pueblo County |
30,000 | 3 | 0 | |
|
Lafayette City of Boulder County |
28,700 | 4 | 0 | |
|
Breckenridge Town of Summit County |
28,315 | 4 | 0 | |
|
FT Lupton City of Weld County |
12,099 | 3 | 1 | |
|
Wellington Town of Larimer County |
11,720 | 5 | 0 | |
|
Morrison Town of Jefferson County |
9,887 | 2 | 0 | |
|
Craig City of Moffat County |
8,930 | 3 | 0 | |
|
Telluride Town of San Miguel County |
7,900 | 6 | 0 | |
|
Manitou Springs City of El Paso County |
6,938 | 1 | 0 | |
|
Carbondale Town of Garfield County |
6,700 | 3 | 0 | |
|
Stratmoor Hills Wsd El Paso County |
6,500 | 6 | 0 | |
|
Georgetown Town of Clear Creek County |
5,315 | 2 | 0 | |
|
Frisco Town of Summit County |
4,495 | 2 | 1 | |
|
Battlement Mesa MD Garfield County |
4,100 | 6 | 0 | |
|
Central City City of Gilpin County |
3,750 | 4 | 0 |
About this data
A system is counted once if any of its violations in the past three years involved Interim Enhanced Surface Water Treatment Rule, including monitoring and reporting lapses. Rules violated and status in the table are for the whole system, not Interim Enhanced Surface Water Treatment Rule alone.
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 Colorado 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.