PlaceDossier / BC places / Lakes / Rankings

BC lakes, ranked

2 rankings of the 906 lakes with clarity or nutrient readings in the province's monitoring records. Clarity ranks only lakes with at least 10 summer readings from open water, spread over at least 3 different years, since 2012; next to every figure is what it rests on.

Clearest lakes

Median summer Secchi depth since 2012, for lakes with at least 10 summer readings from open water, spread over at least 3 different years; the years each lake's median covers are beside it. 62 ranked.

  1. Slocan Lake15.5 m
  2. Chilliwack Lake13 m
  3. Cowichan Lake11.7 m
  4. Christina Lake11.6 m
  5. Whiteswan Lake11.1 m

All 62 →

Most-sampled lakes

Summer readings of clarity, phosphorus and chlorophyll from open water on record, all years; the years each lake's readings span are beside it. 906 ranked.

  1. Lake Koocanusa6,972
  2. Kootenay Lake4,037
  3. Shuswap Lake2,182
  4. Okanagan Lake1,720
  5. Upper Arrow Lake1,681

All 906 →

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 the water receiving its discharge, 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.

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.

More rankings: BC places (farmland, wildfire, wells, climate) and BC aquifers (wells, depth, yield).