Hot water on stable yard?

i would like to get hot water on my stable yard for my horses just like a boiler of some kind on the wall that can give me a bucket of hot water every now and then! i have seen them on other peoples yards like they look like white boxs on the wall in there tack room above a sink and it comes out boiling hot then fills back up again and in 10 mins will give u another tank of hot water! i tryed looking on the net for one but cant find anything was wondering if anyone on here could help me in getting started on getting this sorted?? thanks