Always be aware of the water you are swimming in, especially after a BIG rain storm/squall. A lot of the beaches in Kitsap county with older (beach homes) in established neighborhoods are on septic systems . . . old septic systems. In the 1950s (and prior) some systems allowed the effluent to be released directly into the sound. Some homes are still on this type of system! Additionally, when we have very, very heavy rain storms the waste water treatment plant is permitted to discharge directly into the Sound!
Most beaches in the area are rocky. Very few have sand. Some beaches contain shellfish, oysters, etc. Oysters release an enzyme that slows the healing process. If you receive a cut from a shell it will take a little longer to stop bleeding. Don't wear flips! Be carefull with pets as well. Also be aware of 'sea glass' (broken glass that washes ashore).