Sully Lake
Sully Lake in Sully County, South Dakota is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 212 acres.
- Area
- 212 acres
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Why Sully Lake has no grade
We grade a lake only when the monitoring record supports a letter: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Sully Lake, no water-quality sampling on record for this lake.
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by SD DANR and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Sully Lake is a 212-acre lake in Sully County, South Dakota.
Source: EPA Water Quality Portal sampling records, SD DANR, last sampled recent years. Grade methodology: LakeQuality methodology.
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Swimming Safety
Not ratedElevated nutrients
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Sully Lake
These readings exist but are not enough for an A–F grade — see why.
No clarity data. Trophic State Index: undefined.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) |
Where to stay near Sully Lake
Compare lakeside cabins, hotels, and vacation rentals near Sully Lake in Sully County, South 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.
Top-rated places to stay near Sully Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Surface Area | 212 acres |
No bathymetric survey has been published for Sully Lake, so its depth is not documented here.
Fishing Sully Lake
Nearby Lakes in Sully County
Frequently asked questions about Sully Lake
Where is Sully Lake?
- Sully Lake is a lake in Sully County, South Dakota. LakeQuality has not rated this lake (UNRATED) — no water-quality sampling on record for this lake.
What is the water quality grade for Sully Lake?
- Sully Lake in Sully County, South Dakota is not rated for water quality — its monitoring record does not meet the evidence bar. Surface area: 212 acres.
Is Sully Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Sully Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
Explore Sully Lake across LakeQuality
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Where this data comes from
Measurements for Sully Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.