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Cyanotoxin Monitoring

Results: No Detection

The South Fork Water Board (SFWB) is the wholesale drinking water provider to the Cities of Oregon City and West Linn, and portions of the Clackamas River Water south side service area. SFWB tests for cyanotoxins in the raw water entering the treatment plant every other week from May through October. 

This monitoring is part of the EPA’s Unregulated Contaminants Monitoring Rule (UCMR4), and Oregon Health Athority Rules for Cyanotoxin Monitoring in Drinking Water.

If cyanotoxins levels are detected at or above the Oregon Heath Authority guidelines, the SFWB will notify its customers of any health risks and the necessary precautions individuals should take.

What are cyanotoxins?

Cyanotoxins are toxins produced by bacteria called cyanobacteria (also known as blue-green algae). These are found in all types of water, lake, river, and ocean.

Not all blue-green algae blooms produce toxins, but under certain conditions, such as in warm water containing an abundance of nutrients, they can rapidly form harmful algal blooms capable of producing cyanotoxins that can harm humans and animals.

Does SFWB water treatment filter out cyanotoxins?

Drinking water treatment systems on the Clackamas River can remove the risks to humans and pets from drinking water with cyanotoxins in all conditions except those that may occur during an extremely large and long duration cyanobacteria bloom.  

It is only the blooms that are very large and last a long time that create a risk from drinking the water, because under all other conditions our treatment processes, which are designed to meet all Federal and State Drinking Water health protection mandates, provide multiple layers of protection.

For more information about your drinking water please visit your city website.

Oregon City Water

West Linn Water