Cuesta College across Hwy 1 has a pool. You would need to pay a fee, but a pass could work if you're staying a while.
It's a camp ground no lake but they have showers in the bathrooms your best bet is to go a lil farther to Morro bay
S.l.o..YMCA has a swimming pool where you can shower $2.00 (this is why I hate camping)
Very small creek. Go to the ocean nearby.
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