What I did in a pinch was create a wand using 1/2" PVC that has a valve that can also attach to your garden hose. At the end of the wand I put on a cap and drilled two tiny holes in it. I used it for a tunnel boring machine to get pipe under a walk way and I tried it against the house and it did a great job. It also works well on cleaning dirt bikes after a dirty ride.
I think the key is having good water pressure to start with.... and the valve is a necessity. You could also use the same set up with a spray nozzle that's threaded at the tip to recieve the PVC want, in which case you would not need a valve.
Hope that helps.