Larimer County, Colorado · Water Quality Report Card
The Loch Surface Lake
The Loch Surface Lake in Larimer County, Colorado has a water quality grade of C (Fair). Chlorophyll-a (algae): 3.4 µg/L.
- Type
- Mesotrophic
The Loch Surface Lake is a mesotrophic lake in Larimer County, Colorado. Water quality is graded C based on 1 sampling years through 2020. Compared to the 8 other monitored lakes in Larimer County, The Loch Surface Lake ranks #7 for water quality.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2020-12-29. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
No clarity data. Chlorophyll-a: 3.4 µg/L. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 3.4 µg/L | Fair |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near The Loch Surface Lake
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Fishing The Loch Surface Lake
Location
County Ranking
Ranked #7 of 9 lakes in Larimer County
Cleaner Lakes Within 30 Miles
The Loch Surface Lake holds Grade C. One nearby lake has a higher grade.
Nearby Lakes in Larimer County
Explore The Loch Surface Lake across LakeGrade
8.6 mi away · 25 ft
Species activity outlook by water temperature and season
Where to stay at Colorado's top lakes, each with its grade
Moderate nutrients, good water quality
Colorado's cleanest and most-polluted lakes, ranked
Planning a trip around Rocky Mountain?
The Loch Surface Lake is about 5 miles from Rocky Mountain National Park. Crowds there swing hard by season, so the month you pick changes both how busy the park is and what lodging costs.
Best time to visit Rocky Mountain →More Colorado Lake Rankings
Other Grade C Lakes in Colorado
Mesotrophic Lakes in Colorado
More records, surveys & data sources
Where this data comes from
13 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- USGS Colorado Water Science Center
USGS-CO13 samples · 2020
Monitoring station identifiers (1)
Grade thresholds come from the U.S. EPA National Lakes Assessment 2022 Technical Support Document (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated.
Data Sources
Water quality data from the EPA Water Quality Portal
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion
Most recent sample: 2020-12-29
Monitoring stations: 1