at most hospitals you can, but it depends on the amount of mws on shift at the time you go into labour.
I was down for a water birth, but because there was another 2 girls in labour the exact time as me, and another 3 who had just given birth, there wasnt enough midwives for me, as you have to have at least 2 with you aparently.
I was really upset, they said I could wait and get in a bath whilst they see if they could get the staff, but my labour was super quick so wasnt enough time.
If your hospital does them, then I say go for it, but be prepared to be let down, coz it may not happen.
x