Pearl Lake
Routt County, Colorado166 acresView mapDirections
Nutrients and algae sit mid-range for this region.
↓ down from B at the last regrade
- Oligotrophic
- #1 of 4 in the county
- 22 ft max depth
- Public access
- Limited data
Pearl Lake in Routt County, Colorado has a water quality grade of C (Fair). Water clarity: 14.1 ft visibility. Phosphorus: 12.5 µg/L. Chlorophyll-a (algae): 2 µg/L. Surface area: 166 acres.
- Clarity
- 14.1 ft
- Max depth
- ~22 ft est.
- Area
- 166 acres
- Type
- Oligotrophic
- Public access
- Yes
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Pearl Lake is a 166-acre cold, clear oligotrophic lake in Routt County, Colorado with an estimated average depth of about 22 feet. Water quality is graded C based on 3 sampling years through 2020. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 3 other monitored lakes in Routt County, Pearl Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, CDPHE, last sampled 2020-09-22. Grade methodology: LakeQuality methodology.
What Pearl Lake is good for
From access and monitoring records, not editorial picks.
- Clear water14.1 ft of visibility
- Boat launch1 documented ramp
Swimming Safety
Grade onlyLimited data
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
The C is nutrients and algae, not a swimming clearance. Pearl Lake is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury). Check local advisories before you swim.
Water Quality Grade: C (Fair)
Good clarity, visible to about 14.1 ft. Phosphorus 12.5 µg/L. Chlorophyll-a 2 µg/L. TSI 39. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14.1 ft | Not graded |
| Phosphorus | 12.5 µg/L | Good |
| Chlorophyll-a (Algae) | 2 µg/L | Fair |
| Trophic State Index (TSI) | 39 | Oligotrophic |
Low nutrients, clear water. The letter is not a swimming clearance.
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~22 ft est. |
| Surface Area | 166 acres |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Colorado has not published bathymetry for Pearl Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Recreation & Access
- Pearl Lake State ParkPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Pearl Lake
Reservoir Info (USACE NID)
Pearl Lake is a man-made reservoir impounded by the Lester Creek (completed 1962), built primarily for recreation on the Lester Creek; earth-type dam, 110 ft tall and 525 ft long.
- Surface area
- 166 ac
- Normal storage
- 5,592 ac-ft
- Max storage
- 6,739 ac-ft
- Drainage area
- 4 sq mi
- Hazard class
- High
- Owner
- COLORADO PARKS AND WILDLIFE (TAYLOR, MARGARET)
Source: USACE National Inventory of Dams, NID ID CO01022 · Operator website
EPA Impairment Status
Pearl Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit COUCYA22_D · Official waterbody report
County Ranking
Ranked #1 of 4 lakes in Routt County
Nearby Lakes in Routt County
Frequently asked questions about Pearl Lake
Where is Pearl Lake?
- Pearl Lake is a lake in Routt County, Colorado. LakeQuality grades it C for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Pearl Lake?
- Pearl Lake in Routt County, Colorado has a water quality grade of C (Fair). Water clarity: 14.1 ft visibility. Phosphorus: 12.5 µg/L. Chlorophyll-a (algae): 2 µg/L. Surface area: 166 acres.
Is Pearl Lake safe to swim in?
- The C is nutrients and algae, not a swimming clearance. Pearl Lake is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury). Check local advisories before you swim.
How deep is Pearl Lake?
- No published bathymetric survey covers Pearl Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 22 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate. The lake covers 166 acres.
Are there boat ramps on Pearl Lake?
- Pearl Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Pearl Lake State Park. Public access is listed as yes.
Explore Pearl Lake across LakeQuality
2 thermal springs within 20.8 mi, nearest Routt Hot Springs
Species activity outlook by water temperature and season
Where to stay at Colorado's top lakes, each with its grade
Low nutrients, clear water. The letter is not a swimming clearance.
Colorado's cleanest and most-polluted lakes, ranked
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Other Grade C Lakes in Colorado
Oligotrophic Lakes in Colorado
Where this data comes from
18 measurements from 2 monitoring stations, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Colorado Dept. of Public Health & Environment-WQCD
21COL001_WQX18 samples · 2020
Analytical methods
- Secchi disk depth measurement
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Nitrogen in Water by Pyrolysis Detection
Monitoring station identifiers (2)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Named boat-access points from the USGS National Boat Ramps inventory