A pressure washer is an expensive piece of kit which is probably only used a handful of times each year, but if looked after and stored properly, it will last for years.
Do your best to store the machine in dry conditions, keeping the machine from collecting dirt, dust and mildew. A garage is the perfect place.
Petrol becomes stale after 30 days, so it's always best to remove any surplus petrol before you put it away.
Ensure that the pressure washer is clean when you store it and put the tools away carefully. It's a good idea to store them on a shelf or wind them around a hook. Looking after them will prolong their life.
It is especially important to give your pressure washer some TLC as the winter approaches. Even though a garage is indoors, it will not be heated, so the contents of the garage will be subjected to winter temperatures, indeed the temperatures may fall below freezing. It is essential that you remove all of the water out of the machine when you have finished using it. Otherwise the water may freeze inside the tank when the temperatures plummet and potentially crack the lines. It is also recommended that you cover the pressure washer.