Grass Lake
Parry Sound District, OntarioView mapDirections
Ontario MECP publishes the water-quality measurements for Grass Lake. Here is what has been measured.
Grass Lake in Parry Sound District, Ontario has water-quality measurements published by Ontario MECP, shown here as reported. Water clarity: 5.5 m visibility. Phosphorus: 4.9 µg/L.
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Grass Lake is a lake in Parry Sound District County, Ontario.
Source: Ontario open-data programmes (Lake Partner Program and Broad-scale Monitoring) — not the EPA Water Quality Portal, last sampled 2025-05-14. Grade methodology: LakeQuality methodology.
What Grass Lake is good for
From access and monitoring records, not editorial picks.
- Clear water18 ft of visibility
Swimming conditions
No readingNot rated
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Grass Lake is safe to swim in today is a call for the Ontario Ministry of the Environment, Conservation and Parks and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Grass Lake
These are the measurements Ontario MECP publishes for Grass Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Crystal clear, you can see 18 ft down. Phosphorus 4.9 µg/L. TSI 31.
| Metric | Value | EPA condition class |
|---|---|---|
| Water Clarity (Secchi Depth) | 5.5 m | Measured, not scored |
| Phosphorus | 4.9 µg/L | Measured, not scored |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 31 | Oligotrophic |
Low nutrients, clear water. No reading is a swimming clearance.
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Frequently asked questions about Grass Lake
Ask about Grass Lake
Answers come straight from the public measurements and survey records on this page.
Where is Grass Lake?
- Grass Lake is a lake in Parry Sound District, Ontario. Its water-quality measurements are published by Ontario MECP and shown on this page as reported.
What is the water quality of Grass Lake?
- Grass Lake in Parry Sound District, Ontario has water-quality measurements published by Ontario MECP, shown here as reported. Water clarity: 5.5 m visibility. Phosphorus: 4.9 µg/L.
Is Grass Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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Where this data comes from
Measurements for Grass Lake come from Ontario open-data programmes (Lake Partner Program and Broad-scale Monitoring), not the EPA Water Quality Portal. Per-sample source details are not recorded for this lake. Contains information licensed under the Open Government Licence – Ontario. See data sources.