How Clean Is Lake St Louis?
Lake St Louis does not have enough monitoring data to grade. It does not have enough recent summer sampling for a letter grade, so it is shown unrated. Unrated means the measurements are missing, not that the water is poor. Everything the monitoring record does contain is below. Water clarity (Secchi depth): 2.7 ft. Phosphorus: 50 µg/L. Chlorophyll-a (algae): 74.3 µg/L. Trophic State Index: 65.
Cleanliness Snapshot
| Metric | Lake St Louis | Missouri avg |
|---|---|---|
| Overall Grade | NR | C |
| Water Clarity (Secchi) | 2.7 ft | — |
| Phosphorus | 50 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 74.3 µg/L | <10 = clean |
| Trophic State Index | 65 | <50 = clean |
How does Lake St Louis compare?
Lake St Louis is not rated for water quality: it does not have enough recent summer sampling for a letter grade, so it is not compared with the Missouri state average. Multi-year monitoring data shows water quality is declining based on 5 years of records.
Watch Lake St Louis water quality
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