Serviced pitches vary greatly. Some have the services at the back, some at the side,some have it shared between 2 pitches. 5 metres of waste should do, depending on where your outlets are. Probably 5 metres of water hose too, but safer to take a bit more. We bought a 25metre hose and cut it in half. Have come across 2 different ways of connecting it to the tap, so you need to be prepared with a small selection of connectors.
we have one that we bought the full kit it cost about £50 we have had it about 4 years and used it twice although when we did use it it was good alot of money
------------- "common sence is not so common"...Voltaire