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.
During the 2017 beach season, 62 public beaches on coastlines were sampled from Memorial Day through Labor Day. High-use beaches were sampled weekly or biweekly for enterococcus, a type of fecal bacteria. High enterococcus levels are linked to swimmer illness.
King County saltwater swimming beaches
We sampled 10 King County beaches from May 22 through Sept. 1, 2017 almost every week during the swimming season.
Alki Beach Park
Alki Beach Park was sampled for 14 weeks during the swimming season. Water quality at this beach was good. On July 17, sampling results were in the swim advisory range, but subsequent sampling showed that bacteria levels had dropped into the safe swimming range.
This beach was closed to swimming due to a sewage spill on Feb. 9-10, 2017.
Carkeek Park beach
Carkeek Park beach was sampled for 13 weeks during the swimming season. Water quality at this beach was very good and met the swimming standards during all periods sampled.
Dash Point State Park beach
Dash Point State Park beach was sampled for 15 weeks during the swimming season. This beach had excellent water quality and met the swimming standards during all periods sampled.
Golden Gardens beach
Golden Gardens beach was sampled for 13 weeks during the swimming season. During the 2017 season, this beach had very good water quality and met the swimming standards during all period sampled.
The beach was closed to swimming due to a sewage spill on Feb. 9-21, 2017.
Lincoln Park beach
Lincoln Park beach was sampled for 13 weeks during the swimming season. This beach had very good water quality, meeting the swimming standards during all periods sampled.
A shoreline survey was conducted by BEACH Program staff at this beach on July 12, 2017. A recommendation was made to provide pet waste stations since people were observed walking dogs along the path above the beach.
Redondo County Park beach
Redondo County Park beach was sampled weekly during the swimming season. This beach had good water quality. On July 10, sampling results were in the swim advisory range, but subsequent sampling showed that bacteria levels had dropped into the safe swimming range.
Richey Viewpoint beach
Richey Viewpoint beach was sampled for 12 weeks during the sample season. This beach had very good water quality, meeting the swimming standards during all periods sampled.
Richmond Beach Saltwater Park beach
Richmond Beach Saltwater Park was sampled for 13 weeks during the swimming season. This beach had excellent water quality, meeting the swimming standards during all periods sampled.
Saltwater State Park beach
Saltwater State Park beach was sampled weekly during the swimming season. This beach had excellent water quality, meeting the swimming standards for all periods sampled.
Seahurst Park beach
Seahurst Park Beach was sampled for 13 weeks during the swimming season. This beach had very good water quality, meeting the swimming 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 2017
| Beach |
Geometric Mean |
Statistical Threshold Value |
| Alki Beach Park |
26 |
81 |
| Carkeek Park Beach |
11 |
21 |
| Dash Point State Park Beach |
10 |
13 |
| Golden Gardens Beach |
16 |
32 |
| Lincoln Park Beach |
14 |
38 |
| Redondo County Park Beach |
16 |
45 |
| Richey Viewpoint Beach |
16 |
46 |
| Richmond Beach Saltwater Park |
10 |
16 |
| Saltwater State Park Beach |
13 |
22 |
| Seahurst Park Beach |
14 |
30 |