Clearwater Lake
Mountrail County, North DakotaView mapDirections
Nutrients and algae run above the regional average.
↓ down from C at the last regrade
- Eutrophic
- #5 of 5 in the county
- 8 ft max depth
- Public access
- Limited data
Clearwater Lake in Mountrail County, North Dakota has a water quality grade of D (Nutrient-rich). Water clarity: 2.1 ft visibility. Phosphorus: 56 µg/L. Chlorophyll-a (algae): 4.1 µg/L.
- Clarity
- 2.1 ft
- Max depth
- ~8 ft est.
- Type
- Eutrophic
- Phosphorus
- 56 µg/L
- Chlorophyll-a
- 4.1 µg/L
- Public access
- Yes
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Stays near Clearwater Lake
Compare lakeside cabins, hotels, and vacation rentals near Clearwater Lake in Mountrail County, North Dakota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Clearwater Lake are listed below.
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Clearwater Lake is a productive, nutrient-rich eutrophic lake in Mountrail County, North Dakota with an estimated average depth of about 8 feet. Water quality is graded D based on 1 sampling years through 2024. Limited fish-species data available. Public access is available with 1 public boat landing. Compared to the 4 other monitored lakes in Mountrail County, Clearwater Lake ranks #5 for water quality.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2024-10-03. Grade methodology: LakeQuality methodology.
What Clearwater Lake is good for
From access and monitoring records, not editorial picks.
- 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 D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
Water Quality Grade: D (Nutrient-rich)
Very murky, less than 2.1 ft of visibility. Phosphorus 56 µg/L. Chlorophyll-a 4.1 µg/L. TSI 58. The letter is not a swimming clearance.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.1 ft | Not graded |
| Phosphorus | 56 µg/L | Not graded |
| Chlorophyll-a (Algae) | 4.1 µg/L | Not graded |
| Trophic State Index (TSI) | 58 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | ~8 ft est. |
| Public Access | Yes |
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. North Dakota has not published bathymetry for Clearwater 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
- Clearwater LakePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fishing Clearwater Lake
County Ranking
Ranked #5 of 5 lakes in Mountrail County
Nearby Lakes in Mountrail County
Frequently asked questions about Clearwater Lake
Where is Clearwater Lake?
- Clearwater Lake is a lake in Mountrail County, North Dakota. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Clearwater Lake?
- Clearwater Lake in Mountrail County, North Dakota has a water quality grade of D (Nutrient-rich). Water clarity: 2.1 ft visibility. Phosphorus: 56 µg/L. Chlorophyll-a (algae): 4.1 µg/L.
Is Clearwater Lake safe to swim in?
- The D is nutrients and algae, not a swimming clearance. Check local advisories before you swim.
How deep is Clearwater Lake?
- No published bathymetric survey covers Clearwater Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 8 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Clearwater Lake?
- Clearwater Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Clearwater Lake. Public access is listed as yes.
Explore Clearwater Lake across LakeQuality
Species activity outlook by water temperature and season
Where to stay at North Dakota's top lakes, each with its grade
High nutrients, frequent algae, reduced clarity
North Dakota's cleanest and most-polluted lakes, ranked
More North Dakota Lake Rankings
Other Grade D Lakes in North Dakota
Eutrophic Lakes in North Dakota
Where this data comes from
21 measurements from 1 monitoring station, 2024. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX21 samples · 2024
Analytical methods
- Phosphorus by Colorimetry
- 447.0 ~ EPA; Chlorophyll a and b in phytoplankton by HPLC/UV
- 4500 NO3 E ~ Nitrate in Water- Cadmium Reduction
Monitoring station identifiers (1)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Depth, fish, and access data from North Dakota Game & Fish
Named boat-access points from the USGS National Boat Ramps inventory