yes it'll be fine
a extension lead will be ok, i would get 1 with a "circuit breaker" the plug end, then if anything happened, it would just trip the breaker out, a bit of extra safety
Oh and also get the thickest cable you can, i would make my own with some 40 amp cable ( the heavy duty stuff for cookers and powershowers )
a hose connected will be fine
make sure you have the sockets off the floor, that way, if you have aoverflow of water, you will be safe, though if you use a "circuit breaker" you wll be ok anyways