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 2018, we sampled 62 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 May 21 – Aug. 31, 2018. Beaches were monitored almost every week during the swimming season.
Find details about each of the King County beaches below:
Alki Beach Park was sampled 13 weeks during the swimming season. Water quality at this beach was good and met swimming standards during all periods sampled
Carkeek Park beach was sampled 13 weeks during the swimming season. Water quality at this beach was excellent and met swimming standards during all periods sampled.
Dash Point State Park beach was sampled 15 weeks during the swimming season. This beach had excellent water quality and met swimming standards during all periods sampled.
Golden Gardens beach was sampled 14 weeks during the swimming season. On Aug. 6, 2018, sampling results were in the advisory range, but subsequent sampling showed that bacteria levels had dropped into the safe swimming range. During the 2018 season this beach had good water quality and met the swimming standards during all other periods sampled.
Lincoln Park beach was sampled 14 weeks during the swimming season. On June 4, sampling results were in the advisory range, but subsequent sampling showed that bacteria levels had dropped into the safe swimming range. This beach had good water quality, meeting swimming standards during all other periods sampled.
Redondo County Park beach was sampled 15 weeks during the swimming season. This beach had excellent water quality and met the swimming standards for all periods sampled.
Richey Viewpoint beach was sampled 13 weeks during the sample season. This beach had very good water quality, meeting swimming standards during all periods sampled.
Richmond Beach Saltwater Park was sampled 13 weeks during the swimming season. This beach had excellent water quality, meeting swim standards during all periods sampled.
Saltwater State Park beach was sampled 15 weeks during the swimming season. This beach had very good water quality, meeting swim standards during all periods sampled.
Seahurst Park beach was sampled 12 weeks during the swimming season. This beach had very good 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 35 and the statistical threshold value of enterococcus/100 mL is greater than or equal to 276. We issue a public swimming advisory when enterococcus levels reach 104 per 100 mL of water.
Table: Calculated geometric mean and statistical threshold value at King County beaches (in enterococcus per 100 mL) for 2018
| Beach |
Geometric Mean |
Statistical Threshold Value |
| Alki Beach Park |
16 |
38 |
| Carkeek Park Beach |
11 |
16 |
| Dash Point State Park Beach |
10 |
14 |
| Golden Gardens Beach |
18 |
63 |
| Lincoln Park Beach |
16 |
42 |
| Redondo County Park Beach |
13 |
20 |
| Richey Viewpoint Beach |
22 |
72 |
| Richmond Beach Saltwater Park |
13 |
20 |
| Saltwater State Park Beach |
12 |
21 |
| Seahurst Park Beach |
16 |
30 |