[alistairSH]

Public pools are generally fine. They usually have a small fee to use, so they aren't truly public in the same sense as the local playground. In my area, most pools are county or town operated, with a discount rate for residents and a higher rate for non-residents. Usually, $5-$10/visit for non-residents, which also buys access to the locker room/showers and any gym equipment.

I imagine the public baths in Japan are similar. So, there is an entry fee that funds a small staff to keep the bathhouse in good repair.

Edit - as an aside, I visited Iceland in January. The public baths/pools were amazing. The entry fees were minimal (a few euro, a bit less than entry to a pool in the US). Facilities were all clean and well maintained. But, it's also part of their culture. Like bath-houses in some nations, people go to the pools to hang out and socialize in the evening.