Is Beaver Dam Lake Polluted?
Yes — Beaver Dam Lake in Dodge County, Wisconsin is on the EPA's Clean Water Act 303(d) impaired-waters list (2024 assessment cycle). It is cited for Nutrients (phosphorus, nitrogen). 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 | Dodge County, Wisconsin |
Pollutants Cited
- Nutrients (phosphorus, nitrogen) — Excess phosphorus and nitrogen fuel algae growth and summer blooms. This is the classic agricultural-runoff and shoreline-development impairment, and the one most likely to affect swimming via blue-green algae.
Specific parameters in the EPA record: PHOSPHORUS, TOTAL.
What this means for using Beaver Dam Lake
Because Beaver Dam Lake is listed for Nutrients (phosphorus, nitrogen), swimming can be affected — check for posted beach advisories, especially after heavy rain or during visible algae. 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. Beaver Dam Lake carries an overall water-quality grade of D and phosphorus at 230.5 µg/L — see the full breakdown on the lake report. The official EPA assessment is available in the ATTAINS waterbody report.
Watch Beaver Dam Lake water quality
Get an email when the grade, clarity, or algae reading changes. Unsubscribe anytime.