Hardest Water in Colorado
23 cities ranked by water hardness. Parker tops the list at 210 PPM.
Colorado's water hardness varies significantly by city and water source. The state average across our database is 99 PPM, which is moderately hard. Some cities need treatment while others do not. 26% of cities we track in Colorado have hardness above 120 PPM.
Parker has the hardest water at 210 PPM (12.3 GPG). At this level, expect visible scale on faucets, reduced water heater efficiency, and higher soap usage. A salt-based water softener typically pays for itself within 12-18 months in energy and consumable savings. Boulder North has the softest water at just 40 PPM. No softener is needed.
| # | City | PPM | GPG | Level | Softener? |
|---|---|---|---|---|---|
| 1 | Parker | 210 | 12.3 | Very Hard | Yes |
| 2 | Castle Rock | 200 | 11.7 | Very Hard | Yes |
| 3 | Brighton | 160 | 9.4 | Hard | Recommended |
| 4 | Greeley | 152 | 8.9 | Hard | Recommended |
| 5 | Lafayette | 150 | 8.8 | Hard | Recommended |
| 6 | Aurora East | 120 | 7 | Hard | Recommended |
| 7 | Fort Collins | 105 | 6.1 | Moderately Hard | Optional |
| 8 | Colorado Springs | 101 | 5.9 | Moderately Hard | Optional |
| 9 | Denver | 90 | 5.3 | Moderately Hard | Optional |
| 10 | Fort Collins South | 90 | 5.3 | Moderately Hard | Optional |
| 11 | Arvada | 81 | 4.7 | Moderately Hard | Optional |
| 12 | Thornton | 78 | 4.6 | Moderately Hard | Optional |
| 13 | Boulder | 77 | 4.5 | Moderately Hard | Optional |
| 14 | Centennial | 75 | 4.4 | Moderately Hard | Optional |
| 15 | Aurora | 73 | 4.3 | Moderately Hard | Optional |
| 16 | Lakewood | 73 | 4.3 | Moderately Hard | Optional |
| 17 | Pueblo | 72 | 4.2 | Moderately Hard | Optional |
| 18 | Loveland | 72 | 4.2 | Moderately Hard | Optional |
| 19 | Broomfield | 70 | 4.1 | Moderately Hard | Optional |
| 20 | Longmont | 68 | 4 | Moderately Hard | Optional |
| 21 | Westminster | 66 | 3.9 | Moderately Hard | Optional |
| 22 | Durango | 45 | 2.6 | Slightly Hard | No |
| 23 | Boulder North | 40 | 2.3 | Slightly Hard | No |
Frequently Asked Questions
What is the average water hardness in Colorado?
Across 23 cities in our database, the average water hardness in Colorado is 99 PPM (5.8 GPG). This ranges from 40 PPM in Boulder North to 210 PPM in Parker.
Do I need a water softener in Colorado?
It depends on your city. 26% of Colorado cities in our database (6 of 23) have hardness above 120 PPM where a softener provides measurable benefit. Check your specific city above.
Which Colorado city has the softest water?
Boulder North has the softest water in Colorado at 40 PPM (2.3 GPG). No water softener is needed at this level.
What causes hard water in Colorado?
Hard water in Colorado is caused by dissolved calcium and magnesium from the local geology. Regional geology varies, with some areas having limestone bedrock that adds minerals and others with granite or sandstone that produces softer water.