Public bathing

Walls will definitely help. As long as the bathing sim is not within line of sight of another sims, both should be fine. In my Oldwest save I placed the bathtub outside and while one sim is taking a bath, the others can tend to the chickens or train elsewhere in the yard.

If you have Seasons, you can shower in the rain. ETA: Oh, you're creating a wash house. Nevermind, lol.

Arches count like doors for privacy, so you could separate the bath house in to small rooms connected by arches. It would look open-plan (sort of) but each room would be private.

Half walls and fences count as long as they block line of sight.

There's an outdoor shower in Outdoor Retreat game pack. Hope it helps.

I'm trying to make a public bathing house - do you think half-walls surrounding most of the tub would help?

There are showers in gyms and sims are always walking into my bathroom to continue a conversation and my sim doesn't get embarrassed, but I didn't know if that was some kind of cheat or effect turned off by creators.

I'm not sure about half walls. It depends: Does the game treat them as full walls (blocking sight) or can sims see across them?
I think they count as full walls internally and therefore should work.

In the end I used half-wall cubicles with baths and it seems to be fine. It must be something about community lots. Thanks everyone!