stae, ya my circumstances was being in Latin America, and I was very careful and aware of trying to reduce the risk of a crappy riding experience. Food was something I couldnt control (to a certain extent yes I could) but water I could definitely control by filtering my own water every morning before heading out. Did my bike bottles and spare bottles in my pannier, how much depending on the area and heat. Often rode with about 4 litres , then supplemented with corner store or gas station cold drinks.
and yes, I too read up on the whole uv thing, of how municipal services have been using it for a long time, and if done properly, has a pretty good track record.
oh, and tourist touched on an important thing, of not contaminating your uv'd water with non treated stuff. I tried to be very careful of this. Steripened water in a large mug, then carefully poured it into my bike bottles or spare 2 L bottles.