A pressure washer typically is a standalone unit that is connected to a water supply by a garden hose. However, you can use an air hose for a pressure washer by using a pressure washer attachment that connects to the air hose of an air compressor and to a garden hose. This will allow you to increase the pressure when spraying water from your garden hose without buying a separate power washer.
Turn on the air compressor, and let it build up pressure. Look at the gauge on the air compressor to see the current PSI level. The pressure level of the compressor needs to reach at least 30 PSI.
Connect one end of a garden hose to a faucet on the outside of your house or garage.
Connect the other end of the garden hose to the water line connection on the pressure washer attachment. The water line connection is the threaded connector on the gun.
Plug the air hose from the air compressor into the air line connector. Push the connector on the end of the air hose onto the nipple on the attachment until you hear a popping sound.
Turn on the faucet to allow water to flow through the garden hose.
Point the pressure washer attachment at the area to spray, such as the floor, and then press the trigger.
You can purchase a pressure water attachment, such as the Amflo 2000G, from many retailers using the Google Products web page. After constant use, the PSI in the air compressor will go down and it will need to recharge or increase PSI in the tank. PSI stands for pounds per square inch.
If the air compressor does not have enough PSI built up in the tank, there will be no pressure available to use the pressure washer attachment.