Most of us find cleaning concrete quite tough and you will find a simple as well as a hard way to do it. You need to understand one thing when you are pressure washer cleaning concrete that it may not be possible always to make the concrete to look absolutely new once it has been stained. You may be able to make the stains lighter or bleach them but it may not be possible to completely eliminate them. You may be lucky sometimes but when you are want perfect results most probably you will be disappointed. When you are discussing this with your clients you must tell them up front as well as explain the situation otherwise they will be expecting a task which is not possible to be done unless you remove the complete concrete slab and re-pour it.
Now we can discuss the equipment which is required to get this kind of work done. You have to keep in mind that safety is the top most priority when you are working using a pressure washer. You may even need chemicals for eliminating some of the stubborn stains and you must use some kind of eye protection always. If you are making use of chemicals you must wear thick jeans to safeguard your legs. You must not play around with chemicals which are designed to clean concrete as they are very strong. It is good to wear rubber boots or get rubber waders as they will prevent your feet from getting burned by hot water as well as getting wet.
It is a good idea to place orange cones when you are doing the job. They tell people visually that some work is going on especially if you are cleaning concrete in an area with high traffic or plenty contract workers are present like a newly constructed building which needs concrete cleaning. This will keep everyone safe and you will help in preventing accidents.
You will need a Hydro-Twister to get the concrete cleaning done. It is possible to do it technically with a wand but that takes more water and time. It can even create streaking if even strokes are not being used across the concrete slab. You get the option of hydro twister kind unit in most of the latest hot water pressure washers but if it is not available in yours you can think of buying another unit.