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Whatcom County Health Department
Drinking Water Program, Environmental Health Division
Phone: (360) 676-6724
E-mail: Environmental Health


Blue Green Algae

Toxic Blue Green Algae & Surface Water Users

We are providing you with a link to a website where you can download an information pamphlet entitled “Toxic Blue-Green Algae Blooms”  so that you can make decisions about when and how to avoid toxic blue-green algae blooms in lake water if you use the lake for residential use or recreation activities. (If you are on a public water system please contact the manager of the system for questions). Please also note the following:

Predicitability of blooms

Although blooms can occur anytime, they are more common in warmer summer/fall weather. They may follow a heavy rainfall event after a long dry period (i.e. many nutrients are washed into the lake from storm water).

  • Blooms can cover large or small portions of the lake.
  • Blooms move from day to day due to wind/currents.
  • There can be multiple blooms on the lake at one time at varying stages of maturity.
  • Blooms can change from non-toxic to toxic.


The Whatcom County Health Department will not be testing for toxic blooms because it is:

  • Difficult due to the changing nature of the blooms (see above)
  • Expensive
  • Time consuming
  • Often inconclusive due to the changing nature of the blooms

* Boiling or chlorinating water will not make the water safe.

Lake Samish

Lake Samish, like any surface body of water, will always be subject to contamination and the Health Department does not promote the use of surface water as a private domestic supply. If you see a blue-green algae bloom please follow the advice provide in the pamphlet and notify your neighbors to their presence.

Contact Information

If you have any further questions please contact us:

Whatcom County Health Department
Drinking Water Program, Environmental Health Division
Phone: (360) 676-6724