Ditto for the comment made about spending too much money and not having the district/school maintain it properly. We have used a water delivery company for about two years now, it runs like $700 year(not sure of how much and how often), and the kids are also allowed to bring water bottles. You wouldn't believe how cranky these kids can get if they start to get hot and thirsty! well, i'm sure you can imagine...
Sorry, I don't have a great answer for you. I would just encourage you to check this out pretty thoroughly. We (also in Texas) don't have water fountains outside because they are so difficult to keep in good repair. Your situtation may be different, but I'd worry that we might spend on lot of money on something that the District couldn't/wouldn't be able to afford to maintain.
Our kids just use water bottles in the summer. Nothing fancy - the kids just bring any kind at all and there are always extras. Each is marked with the child's name and stored in a basket in each room. The kids simply fill them up from the water fountain inside.
I'd think that your local plumbers and your school district purchasing office might be a good place to check for leads. They probably already have local contracts which you could use.
Generically, here are some websites for a few of the manufacturers:
Our PTO is planning on buying outdoor water fountains for our playground- we have none!!! We are in south-east TX--it gets pretty hot out there on the playground at the beginning and end of the school year and the kids really want and need cool water. We have not had much luck in finding a reasonably priced company to provide our needs...does anyone have a particular company they may recommend to buy fountains from??