We have quite a large area of patio that gets very slippery, slimey and very very dirty. We were having a party at out house back in May and our patio was a disgrace really black with dirt. My mum had a pressure washer so we borrowed it, plugged it in, hooked it up to the outside tap and I switched on, it is brilliant. Its quite a long job as the patio slabs were black, but within about 60 minutes our patio looked like new, it also got all the weeds out from inbetween the slabs (and some of the cement too, be warned) I was soaked, my shoes were covered in dirt and it looked like I had run through several puddles of dirty water, so make sure you wear a pair of wellies  Read the complete review