Is Lake of the Hills Polluted?
Yes — Lake of the Hills in Scott County, Iowa is on the EPA's Clean Water Act 303(d) impaired-waters list (2024 assessment cycle). It is cited for Algal growth. A formal cleanup plan — a Total Maximum Daily Load (TMDL) — has been written. "Impaired" is a legal designation, separate from the lake's A–F water-quality grade: it means at least one designated use (such as swimming, aquatic life, or fish consumption) does not meet state standards for the listed pollutant.
EPA 303(d) Listing
| On 303(d) impaired list | Listed impaired |
| Cleanup plan (TMDL) | Completed |
| Assessment cycle | 2024 |
| EPA IR category | 4A |
| Location | Scott County, Iowa |
Pollutants Cited
- Algal growth — listed by EPA as exceeding water-quality standards for at least one designated use.
Specific parameters in the EPA record: CHLOROPHYLL-A.
What this means for using Lake of the Hills
Review the EPA assessment and any state advisories before relying on Lake of the Hills for swimming, fishing, or other uses. An impairment listing does not mean the lake is closed — most impaired lakes remain open for boating and swimming. It means a specific pollutant exceeds a standard for a specific use. Lake of the Hills carries an overall water-quality grade of C, with algae (chlorophyll-a) at 16.8 µg/L and phosphorus at 53 µg/L — see the full breakdown on the lake report. The official EPA assessment is available in the ATTAINS waterbody report.
Watch Lake of the Hills water quality
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