[sbubbaklein]

most pressure washers require you to hook up a garden hose to the house as a supply source. There is a small suction hose to draw soap from smaller bottles to mix with the high pressure or just apply with low pressure. Always use a fan patern tip to reduce the possibility of paint damage, hold the tip away from the vehicle, too close again paint damage. Start the engine, turn on supply water quickly. When stoping turn off engine and then supply quickly. You can burn up the pump if no supply water is present.
You can not use most washers by just hanging a hose in a lake, it must have pressurized supply.