$name - King County

Matthews Beach 0818SB

For algal toxin data please visit the State Toxic Algae web page and follow the “Find Lake” menu.

Please select a site and a year

Sample Date	Temperature (°C)	Temperature (°F)	Included in Bacteria Geomean Calculation?	Daily Average Bacteria	Bacteria Geometric Mean – using the three most recent samples
05/16/2022	14.0	57.2	Yes	141

Table Legend

Cell Color	Bacteria Value	Concern Level
	Individual day <= 200 CFU/100 ml	Low Concern - safe for swimming
	Individual day > 200 & <= 1000 CFU/100 ml	Moderate Concern – still safe for swimming
	Individual day > 1000 CFU/100 ml or geometric mean > 200 CFU/100 ml	High Concern – probable closure. For more information see Beach Closure Protocol

NOTE: Beach closure and reopening decisions are made by Public Health – Seattle & King County. Decisions are based on these results plus additional information about beach conditions, and may not always match the concern levels shown here.

Redirecting to NWToxicAlgae site...

Seattle Parks and Recreation

Due to high bacteria counts, do not wade in Thornton Creek
Learn more about the pump station