Is Guelph Lake safe to swim in?

Generally safe for swimming, moderate water quality. Guelph Lake has an overall water quality grade of C. Always check local health department advisories before swimming.

Wellington County, Ontario · Water Quality Report Card

Guelph Lake

Grade C — Fair

Eutrophic

Guelph Lake in Wellington, Ontario received a water quality grade of C (Fair). Water clarity: 0.8 m visibility. Phosphorus: 24.6 µg/L.

Clarity: 0.8 m
Type: Eutrophic

Where to stay →Safe to swim?

Guelph Lake is a productive, nutrient-rich eutrophic lake in Wellington County, Ontario. Water quality is graded C based on 2 sampling years through 2017. Compared to the 5 other monitored lakes in Wellington County, Guelph Lake ranks #5 for water quality.

Source: EPA Water Quality Portal sampling records, Ontario MECP, last sampled 2017-05-08. Grade methodology: LakeGrade methodology.

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Swimming Safety

Generally safe for swimming, moderate water quality

Compare the safest swimming lakes near Erie →

Water Quality Grade: C, Fair

Very murky, less than 2.6 ft of visibility. Phosphorus level: 24.6 µg/L. Trophic State Index: 57.

Metric	Value	Grade
Water Clarity (Secchi Depth)	0.8 m	F
Phosphorus	24.6 µg/L	B
Chlorophyll-a (Algae)	No data
Trophic State Index (TSI)	57	Eutrophic

High nutrients, frequent algae, reduced clarity

Where to stay near Guelph Lake

Compare lakeside cabins, hotels, and vacation rentals near Guelph Lake in Wellington, Ontario — 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.

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Fishing Guelph Lake

→ Guelph Lake fishing regulations (limits, seasons, special rules)

Location

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County Ranking

Ranked #5 of 6 lakes in Wellington

Cleaner Lakes Within 30 Miles

Guelph Lake holds Grade C. 5 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Wellington

Explore Guelph Lake across LakeGrade

Lake Fishing Forecast

Species activity outlook by water temperature and season

Eutrophic Lakes

High nutrients, frequent algae, reduced clarity

The State of Ontario's Lakes

Ontario's cleanest and most-polluted lakes, ranked

More Ontario Lake Rankings

Cleanest lakes in Ontario

Top 25 by overall water quality score

Clearest lakes in Ontario

Top 25 by Secchi water clarity

Best swimming lakes in Ontario

Grade A/B + low algae filter

Family fishing lakes in Ontario

Panfish-rich, public access

All Ontario lakes

Full state directory

Other Grade C Lakes in Ontario

Four Wells Lake

Region of Waterloo · 1 m

Peel Region · 2.8 m

Perth · 1.5 m

Simcoe · 1.8 m

Durham Region · 1.7 m

Arran Lake

Bruce · 2.4 m

Eutrophic Lakes in Ontario

Four Wells Lake Palgrave Mill Pond Gibson Lake Grenadier Pond

More records, surveys & data sources

Where this data comes from

Measurements for Guelph Lake come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.

Data Sources

Water quality data from the EPA Water Quality Portal

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion

Most recent sample: 2017-05-08

Monitoring stations:

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