Keeping beaches safe
The Beach Environmental Assessment, Communication & Health (BEACH) Program ensures that marine water is safe to swim and play in and informs the public if water doesn't meet swimming standards.
From Memorial Day through Labor Day in 2020, we sampled 63 public high-use beaches statewide, either weekly or biweekly, for enterococcus, a type of fecal bacteria. High enterococcus levels are linked to swimmer illness.
King County saltwater swimming beaches
We monitored 10 beaches in King County from June 1 – Aug. 31, 2020. Beaches were monitored every week during the swimming season.
Find details about each of the King County beaches below:
Alki Beach Park was sampled 10 times during the 2020 swim season. Water quality at this beach was excellent and met swimming standards during all sampling events.
Carkeek Park was sampled 10 times during the 2020 swim season. This beach had one sampling event with elevated bacteria results. On June 29, results were in the advisory range, but subsequent samples showed bacteria levels dropped into the safe swimming range. This beach met the swimming standard for all other periods sampled.
Dash Point State Park beach was sampled 14 weeks during the swimming season. This beach had excellent water quality and met swimming standards during all periods sampled.
Golden Gardens beach was sampled 10 times during the 2020 swim season. This beach had very good water quality and met the swimming standards during all sampling events.
Lincoln Park beach was sampled 10 times during the 2020 swim season. This beach had excellent water quality, meeting swimming standards during all periods sampled.
Redondo County Park beach was sampled 14 times during the 2020 swim season. This beach had one sampling event with elevated bacteria results. On June 8, results were in the advisory range, but subsequent samples showed bacteria levels dropped into the safe swimming range. This beach met the swimming standard for all other periods sampled.
Richey Viewpoint beach was sampled 10 times during the 2020 swim season. This beach had excellent water quality, meeting swimming standards during all periods sampled.
Richmond Beach Saltwater Park was sampled nine times during the 2020 swim season. This beach had excellent water quality, meeting swim standards during all periods sampled.
This beach was preemptively closed due to a sewage spill from Dec. 24 – Dec.28.
Saltwater State Park beach was sampled 14 times during the 2020 swim season. This beach had excellent water quality, meeting swim standards during all periods sampled.
This beach was preemptively closed due to a sewage spill from Sept. 17 – Oct. 22.
Seahurst Park Beach was sampled 10 times during the 2020 swim season. This beach had excellent water quality, meeting swim standards during all periods sampled.
Data summary: Bacteria results compared to standards
The chart below summarizes the bacteria levels at King County beaches in relation to the EPA swimming standard or saltwater swimming criteria. Beaches are considered unsafe for swimming when the geometric mean of enterococcus/100 mL of water is greater than or equal to 30 and the statistical threshold value of enterococcus/100 mL is greater than or equal to 110. We issue a public swimming advisory when enterococcus levels exceed 104 per 100 mL of water.
Table: Calculated geometric mean and statistical threshold value at King County beaches (in enterococcus per 100 mL) for 2020.
|
Beach
|
GM
|
STV
|
|
Alki Beach Park
|
12
|
18
|
|
Carkeek Park
|
15
|
16
|
|
Dash Point State Park
|
9
|
11
|
|
Golden Gardens
|
16
|
32
|
|
Lincoln Park
|
12
|
15
|
|
Redondo County Park
|
16
|
56
|
|
Richey Viewpoint
|
17
|
31
|
|
Richmond Beach Saltwater Park
|
10
|
14
|
|
Saltwater State Park
|
12
|
22
|
|
Seahurst Park
|
10
|
14
|
|