Barton Springs is like no other

Is there anywhere else in the country where you can: 1. Swim all year without a wetsuit 2. Swim in an easily accessible, central to town setting 3. Swim in unchlorinated but clean water 4. Swim with animals and plants 5. Have a swimming culture where it’s safe and there’s always someone around?

The only other place I can think of is San Marcos, but wondering if anyone has experienced places like this elsewhere in the US? Also curious about globally although the likelihood of being able to move out of the country is less for me.