Larimer County Lake Quality
Colorado, 7 lakes, average grade D (Poor)
Only 7 lakes in Larimer County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county. The county-wide average grade is D — water quality issues are persistent across most of the monitored basins. 0 lakes fall into the F bracket outright.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Dowdy Lake (C) is the cleanest in the county.
Quick Answers for Larimer County
Planning a trip? Check special fishing regulations for Dowdy Lake — or check the official Colorado fishing regulations.
All Lakes in Larimer County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Dowdy Lake | C | 8.2 ft | - |
| 2 | Carter Reservoir | C | 6.9 ft | - |
| 3 | Lon Hagler Reservoir | D | 4.6 ft | - |
| 4 | Chambers Lake | D | 5.1 ft | - |
| 5 | Boyd Lake | D | 4.6 ft | - |
| 6 | Douglas Reservoir | D | 4.1 ft | - |
| 7 | Timnath Reservoir | D | 5.6 ft | - |
Other Counties in Colorado
See how Larimer County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 12 states.
Where to stay near Larimer County
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Source: EPA National Aquatic Resource Surveys, 2026.