Patterson Lake
Stark County, North DakotaView mapDirections
ND DEQ publishes the water-quality measurements for Patterson Lake. Here is what has been measured.
- Eutrophic
- Impaired · Nutrients (phosphorus, nitrogen)
- Public access
- Limited data
Patterson Lake in Stark County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Phosphorus: 293.5 µg/L. Chlorophyll-a (algae): 7.8 µg/L.
Patterson Lake is a productive, nutrient-rich eutrophic lake in Stark County, North Dakota. Limited fish-species data available. Public access is available. Compared to the 2 other monitored lakes in Stark County, Patterson Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, NDDEQ, last sampled 2023-07-14. Methodology: how these readings are compared.
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Patterson Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen), sediment / turbidity, turbidity. Check local advisories before you swim.
Whether Patterson Lake is safe to swim in today is a call for the North Dakota Department of Environmental Quality and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Patterson Lake
These are the measurements ND DEQ publishes for Patterson Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 293.5 µg/L. Chlorophyll-a 7.8 µg/L. TSI 68.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 294µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 7.8µg/L | Good GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 68 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Patterson Lake
Answers come straight from the public measurements and survey records on this page.
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Stays near Patterson Lake
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Fishing Patterson Lake
EPA Impairment Status
Patterson Lake is officially listed as impaired under Clean Water Act §303(d) in the 2022 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit ND-10130202-002-L_00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Patterson Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Richardton City OfRichardton · 3.2 mi away · NPDES ND0020109Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Nearby Lakes in Stark County
Frequently asked questions about Patterson Lake
Where is Patterson Lake?
- Patterson Lake is a lake in Stark County, North Dakota. Its water-quality measurements are published by ND DEQ and shown on this page as reported.
What is the water quality of Patterson Lake?
- Patterson Lake in Stark County, North Dakota has water-quality measurements published by ND DEQ, shown here as reported. Phosphorus: 293.5 µg/L. Chlorophyll-a (algae): 7.8 µg/L.
Is Patterson Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Patterson Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for nutrients (phosphorus, nitrogen), sediment / turbidity, turbidity. Check local advisories before you swim.
Can I fish at Patterson Lake?
- Public access to Patterson Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by North Dakota's fish and wildlife agency, so check its current regulations before you go.
Explore Patterson Lake across LakeQuality
Planning a trip around Theodore Roosevelt?
Patterson Lake is about 35 miles from Theodore Roosevelt 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 Theodore Roosevelt →More lakes in North Dakota
Other Lakes in North Dakota
Eutrophic Lakes in North Dakota
Where this data comes from
15 measurements from 3 monitoring stations, 2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- North Dakota Department Of Environmental Quality
21NDHDWQ_WQX15 samples · 2023
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 (3)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)