Castaic Lake Lagoon has a nice swimming area with lots of life guards. The water (lake with beach) is very cloudy (2 ft visibility at best), and it's chlorinated. Unfortunately, the entrance fee is $11 per car and the bathrooms are rustic (no TP, no soap, and dirty). There are shade trees and some grass for picnicking.
Pros: Close to the city, beach with swimming area on a lake
Cons: Dirty bathrooms, $11 entrance fee (per car)
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