Originally Posted by BlooMule
Just remember, your water supply has to be higher than the GPM of the washer..... if the garden hose only supplys 2 GPM, your washer can't supply 3GPM and will run dry.
(My water pressure and flow is terrible- even my old electric Karcher will run dry if I have the lawn sprinkler running at the same time)
This is true to a certain point but if the flow of hose is 2 gpm adding a pressure washer will effectively increase that flow. Maybe not a lot but you could probably get 2.5 gpm output out of the washer. Most people though shouldn't have to worry since a house with a 5/8" water meter and decent pressure should easily be running 5-10 gpm. If you have a 3/4" meter or bigger it could be a lot more. You need a big pressure washer to exceed those numbers. This is dependant on how your plumbing is run also. Running it from a tap closest to the meter and as wide and as short of a hose as possible is also a plus.