Adams County Lake Quality
Colorado, 12 lakes — no lake here has enough monitoring data for a grade
Adams County has 12 monitored lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. No lake in Adams County has enough sampling behind it for an A–F grade yet. The 12 monitored lakes below carry whatever clarity, phosphorus, and chlorophyll-a measurements exist.
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.
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Quick Answers for Adams County
Planning a trip? Check special fishing regulations for Barr Lake — or check the official Colorado fishing regulations.
All Lakes in Adams County
12 lakes · 0 graded, 12 not rated0 graded lakes · 12 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| NRBarr LakeAdams | NR | 3.9 ft | No recent samples | No recent samples | No recent samples | ✓ Public | |
| NRBoot Lake ReservoirAdams | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLandora LakeAdams | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRDerby LakeAdams | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRReservoir FAdams | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRReservoir CAdams | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NROhio Lake ReservoirAdams | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NREastlake Reservoir Number ThreeAdams | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRSmith ReservoirAdams | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRMcKay LakeAdams | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRMayham LakeAdams | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLake SangracoAdams | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded |
NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
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Other Counties in Colorado
See how Adams County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all United States (49 states), Canada (Ontario and Québec), and 38 other country hubs..
Source: EPA National Aquatic Resource Surveys, 2026.