PlaceDossier / BC places / Lakes

BC lake · 21 km² · Comox watershed

Comox Lake

Too few readings to judge this lake: 81 summer readings from open water between 2005 and 2015, and we need at least 10 summer readings from open water, spread over at least 3 different years, since 2012 before we summarise or compare it. The readings are below.

The readings

81 summer readings from open water on record from 2005 to 2015, at 3 sampling sites.

Median since 2012Compared with BC lakes
Secchi depthToo few readings to judge
2 readings since 2012, in 1 year
Too few readings to compare (2 readings since 2012, in 1 year).
Total phosphorusToo few readings to judge
3 readings since 2012, in 1 year
Too few readings to compare (3 readings since 2012, in 1 year).
Chlorophyll aToo few readings to judge
3 readings since 2012, in 1 year
Too few readings to compare (3 readings since 2012, in 1 year).
Secchi depth how deep a black-and-white disc stays visible: deeper means clearer water
051015 200520102015 2005: median 12 m from 9 readings2006: median 11 m from 8 readings2007: median 9.0 m from 8 readings2008: median 11 m from 1 reading2015: median 14.7 m from 2 readingsm
Total phosphorus the nutrient that most often feeds algae in BC lakes
310 200520102015 2005: median 2.0 µg/L from 9 readings2006: median 2.0 µg/L from 5 readings2007: median 2.0 µg/L from 8 readings2015: median 2.0 µg/L from 3 readingsµg/L
Chlorophyll a the green pigment in algae: a direct measure of how much is growing
13 200520102015 2005: median 0.5 µg/L from 9 readings2006: median 0.6 µg/L from 8 readings2007: median 1.0 µg/L from 8 readings2015: median 0.6 µg/L from 3 readingsµg/L

Median each year (bigger dot, more readings)Middle half of BC lakesBC median

Source: BC Environmental Monitoring Data System (EnMoDS) results, Environmental Monitoring and Analysis Branch, Province of BC, records to September 19, 2026 (Open Government Licence – British Columbia); lake outlines and names: Freshwater Atlas lakes, Province of BC (Open Government Licence – British Columbia). Summaries by PlaceDossier.

Nutrient level Inferred

Unclear: too few readings to judge this lake's nutrient level.

Left out for too few recent readings (we need at least 10 summer readings from open water, spread over at least 3 different years, since 2012): secchi depth (2 readings since 2012, in 1 year); total phosphorus (3 readings since 2012, in 1 year); chlorophyll a (3 readings since 2012, in 1 year).

Year by year

YearSecchi depthTotal phosphorusChlorophyll a
201514.7 m (2)2.0 µg/L (3)0.6 µg/L (3)
200811 m (1)––
20079.0 m (8)2.0 µg/L (8)1.0 µg/L (8)
200611 m (8)2.0 µg/L (5)0.6 µg/L (8)
200512 m (9)2.0 µg/L (9)0.5 µg/L (9)

Median of each year's May to October readings; the number of readings is in brackets.

Source: BC Environmental Monitoring Data System (EnMoDS) results, Environmental Monitoring and Analysis Branch, Province of BC, records to September 19, 2026 (Open Government Licence – British Columbia); lake outlines and names: Freshwater Atlas lakes, Province of BC (Open Government Licence – British Columbia). Summaries by PlaceDossier.

Where it was sampled

  • E259499 Outlet basin, mid Lake 34 readings
  • E259497 Inlet basin - mid Lake 24 readings
  • E259498 Main basin, mid Lake 23 readings

Site names are tidied from the provincial records; the IDs find each site's full record there.

What this record doesn't cover

Algae bloom reports and invasive mussel checks aren't in this record: the province's Algae Watch map and mussel monitoring aren't published as open data. For swimming, check the regional health authority's beach advisories; for blooms and mussels, ask the province's regional environment office or the local lake association.

Readings are from the province's monitoring database: samples taken by provincial staff, volunteer lake monitors, and companies and local governments that sample under their permits. We keep the ice-free season (May to October), and for phosphorus and chlorophyll only samples from the top 5 m. We leave out sites whose names put them at a water intake, a sewage or industrial outfall, a mine or a permit holder's works, or on the shore (a beach, dock or boat launch): water there can differ a lot from the open lake. Each year's figure is the median of that year's readings. We give a lake a summary, a comparison with other lakes and a nutrient level only when it has at least 10 summer readings from open water, spread over at least 3 different years, since 2012; the summary is the median of those readings. With fewer, or only older ones, we show the readings and say there are too few to judge the lake. A reading below the lab's detection limit counts at that limit. One site can be a bay rather than the open lake, so a lake's figures can differ from one end to the other.

Water quality changes with the season, the weather and the part of the lake. These are past readings, not a test of the water today: before you buy, ask the local government and the lake association what's known, and test a drinking-water intake yourself.