Admittedly I haven't been to all lakes in California, but one time I went to Lake Shasta to do house boating for a week, and nearly every beach we landed on/near was littered with everything from old tires to car batteries to shotgun shells, plus the usual food/drink garbage.

I'd personally rather not allow "all recreation" in reservoirs used for drinking water.

Here’s the thing, all these reservoirs still allow boating, camping, etc, which contribute to the problems you're mentioning. They are already allowed. I’m just saying, it’s silly to not allow swimming as well. If you’d like to ban reservoir contact in totality, that’s one thing, but to not allowing swimming in the lake while all other activity is alllowed is just ridiculous.

That’s bay are drinking water reservoirs - which are not “most of CA reservoirs”.

Just look at the parent website, all of the largest reservoirs listed there, and most of the others, allow swimming and water recreation.

If you read the citation and subsequent law, it’s most CA reservoirs, not just Bay Area. That just happens to be an article for the Bay Area.

For instance, I live in Santa Barbara and all of our local reservoirs have human contact bans.