Copper in Colorado Drinking Water
Ranked by 90th percentile copper level (mg/L) · Data from EPA SDWIS & UCMR
Copper in Colorado: what the data shows
Colorado has 78 cities with copper monitoring data. The state average 90th percentile copper level is 6.090 mg/L, compared to 28.808 mg/L nationally — better than the national average. 78 cities exceed the EPA action level of 1.3 mg/L. Copper in drinking water typically comes from corrosion of copper pipes and plumbing fixtures, particularly in older homes. The EPA action level of 1.3 mg/L is the 90th percentile threshold — if more than 10% of tap samples exceed it, utilities must take corrective action including adjusting water chemistry to reduce corrosivity. Short-term copper exposure above the action level can cause gastrointestinal distress. Long-term exposure at elevated levels is associated with liver and kidney damage. Flushing your tap for 30 seconds before use and using an NSF 53-certified filter can reduce copper exposure.
Cities exceeding 1.3 mg/L EPA Action Level
Copper data across Colorado
Each dot is a city, colored by overall water quality grade. Cities with copper levels above the 1.3 mg/L EPA action level are highlighted. Size reflects population served.
Top 10 cities by copper level in Colorado
Highest Copper levels (mg/L)
All Colorado cities ranked by copper level
| # | City | Level | Level | Exceeds? | Violations | Grade |
|---|---|---|---|---|---|---|
| 1 | Parker | 320.000 mg/L | Yes | 4 | F | |
| 2 | Denver | 11.062 mg/L | Yes | 104 | F | |
| 3 | Antonito | 4.830 mg/L | Yes | 17 | F | |
| 4 | Littleton | 4.124 mg/L | Yes | 16 | F | |
| 5 | Colorado Springs | 3.900 mg/L | Yes | 117 | F | |
| 6 | Idaho Springs | 3.520 mg/L | Yes | 28 | B | |
| 7 | Carbondale | 3.320 mg/L | Yes | 77 | F | |
| 8 | Lyons | 3.320 mg/L | Yes | 61 | D | |
| 9 | Peyton | 2.820 mg/L | Yes | 2 | B- | |
| 10 | Tabernash | 2.600 mg/L | Yes | 0 | A | |
| 11 | Castle Rock | 2.320 mg/L | Yes | 20 | F | |
| 12 | Brighton | 2.300 mg/L | Yes | 18 | F | |
| 13 | Boulder | 2.260 mg/L | Yes | 15 | F | |
| 14 | Aurora | 2.250 mg/L | Yes | 22 | F | |
| 15 | Eagle | 2.230 mg/L | Yes | 4 | C+ | |
| 16 | Highlands Ranch | 2.200 mg/L | Yes | 0 | B- | |
| 17 | Akron | 2.140 mg/L | Yes | 4 | B | |
| 18 | Towoac | 2.110 mg/L | Yes | 5 | D | |
| 19 | Lake City | 2.050 mg/L | Yes | 1 | A- | |
| 20 | Montrose | 2.000 mg/L | Yes | 7 | F | |
| 21 | Berthoud | 2.000 mg/L | Yes | 8 | C+ | |
| 22 | Fraser | 2.000 mg/L | Yes | 0 | C- | |
| 23 | Cripple Creek | 2.000 mg/L | Yes | 1 | B | |
| 24 | Del Norte | 2.000 mg/L | Yes | 4 | B | |
| 25 | Lafayette | 1.980 mg/L | Yes | 19 | F | |
| 26 | Glenwood Springs | 1.970 mg/L | Yes | 17 | F | |
| 27 | Milliken | 1.949 mg/L | Yes | 0 | B | |
| 28 | Morrison | 1.900 mg/L | Yes | 12 | C+ | |
| 29 | Norwood | 1.900 mg/L | Yes | 44 | B- | |
| 30 | South Fork | 1.900 mg/L | Yes | 8 | D | |
| 31 | Hotchkiss | 1.870 mg/L | Yes | 145 | F | |
| 32 | Aspen | 1.850 mg/L | Yes | 2 | D | |
| 33 | Indian Hills | 1.800 mg/L | Yes | 8 | B | |
| 34 | Mount Crested Butte | 1.790 mg/L | Yes | 0 | A- | |
| 35 | Fort Lupton | 1.780 mg/L | Yes | 35 | D | |
| 36 | Woodland Park | 1.730 mg/L | Yes | 55 | D | |
| 37 | Dillon | 1.720 mg/L | Yes | 0 | C+ | |
| 38 | Walden | 1.700 mg/L | Yes | 1 | B | |
| 39 | Wheat Ridge | 1.680 mg/L | Yes | 56 | D | |
| 40 | Minturn | 1.680 mg/L | Yes | 2 | B+ | |
| 41 | Evergreen | 1.650 mg/L | Yes | 57 | F | |
| 42 | San Luis | 1.622 mg/L | Yes | 9 | D | |
| 43 | Platteville | 1.620 mg/L | Yes | 0 | B+ | |
| 44 | Lakewood | 1.610 mg/L | Yes | 28 | F | |
| 45 | Steamboat Springs | 1.600 mg/L | Yes | 57 | F | |
| 46 | Sterling | 1.600 mg/L | Yes | 29 | C- | |
| 47 | Buena Vista | 1.600 mg/L | Yes | 13 | F | |
| 48 | Grand Lake | 1.600 mg/L | Yes | 3 | B+ | |
| 49 | Pagosa Springs | 1.580 mg/L | Yes | 25 | F | |
| 50 | Crestone | 1.580 mg/L | Yes | 2 | B- | |
| 51 | Ignacio | 1.570 mg/L | Yes | 6 | F | |
| 52 | La Veta | 1.550 mg/L | Yes | 26 | F | |
| 53 | Centennial | 1.500 mg/L | Yes | 18 | F | |
| 54 | Silverthorne | 1.500 mg/L | Yes | 3 | D+ | |
| 55 | Silt | 1.500 mg/L | Yes | 28 | F | |
| 56 | Colorado City | 1.500 mg/L | Yes | 34 | F | |
| 57 | Edwards | 1.500 mg/L | Yes | 43 | C | |
| 58 | Evans | 1.490 mg/L | Yes | 0 | B+ | |
| 59 | Poncha Springs | 1.490 mg/L | Yes | 1 | A- | |
| 60 | Durango | 1.480 mg/L | Yes | 112 | F | |
| 61 | Crawford | 1.470 mg/L | Yes | 31 | F | |
| 62 | Limon | 1.440 mg/L | Yes | 3 | A- | |
| 63 | Divide | 1.440 mg/L | Yes | 49 | F | |
| 64 | Ft Morgan | 1.440 mg/L | Yes | 61 | F | |
| 65 | Monument | 1.430 mg/L | Yes | 23 | F | |
| 66 | Ridgway | 1.430 mg/L | Yes | 11 | D+ | |
| 67 | Nucla | 1.420 mg/L | Yes | 9 | D | |
| 68 | Telluride | 1.410 mg/L | Yes | 21 | D | |
| 69 | Lochbuie | 1.410 mg/L | Yes | 1 | A- | |
| 70 | Cedaredge | 1.400 mg/L | Yes | 67 | D | |
| 71 | Copper Mountain | 1.400 mg/L | Yes | 1 | B+ | |
| 72 | Hillrose | 1.400 mg/L | Yes | 15 | B+ | |
| 73 | Elizabeth | 1.400 mg/L | Yes | 5 | B | |
| 74 | Collbran | 1.400 mg/L | Yes | 0 | A- | |
| 75 | Greenwood Village | 1.390 mg/L | Yes | 24 | F | |
| 76 | Loveland | 1.350 mg/L | Yes | 50 | F | |
| 77 | La Junta | 1.350 mg/L | Yes | 245 | F | |
| 78 | Granby | 1.350 mg/L | Yes | 9 | C- |
Frequently asked questions about copper in Colorado
Is copper in Colorado drinking water safe?
78 cities in Colorado exceed the EPA action level of 1.3 mg/L for copper. The state average is 6.090 mg/L. Copper levels are highest in homes with copper plumbing, particularly when water sits in pipes overnight. Flushing the tap before use significantly reduces copper in drinking water.
What causes high copper levels in Colorado tap water?
Copper typically leaches from copper pipes and brass fittings within homes, not from the water source itself. Corrosive (low pH or soft) water accelerates this leaching. Water utilities with high copper readings are required to adjust water chemistry to reduce corrosivity. You can reduce exposure by flushing your tap for 30 seconds before use.