
Summit County Lake Quality
Utah, 28 lakes, average grade C (Fair)
There are 28 monitored lakes in Summit County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. 5 of those lakes carry an A–F grade. The county-level summary describes that subset, not every water body listed. Summit County averages to a C. The distribution behind that average matters more than the letter: a few stressed lakes versus many decent ones can produce the same average as the inverse.
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. Lyman Lake (B) is the cleanest in the county.
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Quick Answers for Summit County
Planning a trip? Check special fishing regulations for Lyman Lake — or check the official Utah fishing regulations.
All Lakes in Summit County
28 lakes · 5 graded, 23 not rated5 graded lakes · 23 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | BLyman LakeSummit | B | 19.7 ft | 10.3 µg/L | 2.1 µg/L | No recent samples | Not recorded |
| 2 | BBeaver Meadow ReservoirSummit | B | 4.6 ft | 22 µg/L | 4.9 µg/L | No recent samples | Not recorded |
| 3 | CSmith And Morehouse ReservoirSummit | C | 7.5 ft | 8.2 µg/L | 3.5 µg/L | No recent samples | ✓ Public |
| 4 | DWhitney ReservoirSummit | D | 17.7 ft | 23 µg/L | 8 µg/L | No recent samples | Not recorded |
| 5 | DHoop LakeSummit | D | 5.6 ft | 45 µg/L | 13 µg/L | No recent samples | Not recorded |
| NRRockport Mid LakeSummit | NR | 12.3 ft | No recent samples | No recent samples | No recent samples | ✓ Public | |
| NREcho Mid Res LakeSummit | NR | 10.4 ft | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRBarker ReservoirSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRFish LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRBoyer LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRBig Elk LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLong LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRMeadow LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRTamarack LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRFish LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRIsland LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRCoffin LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRBeaver LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRChina LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLake BlanchardSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRCliff LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRSmiths Fork Pass LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRMcPheters LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRRed Castle LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRUpper Red Castle LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLower Red Castle LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRFish LakeSummit | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRAmethyst LakeSummit | 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 Utah
See how Summit 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, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs..
Source: EPA National Aquatic Resource Surveys, 2026.