I need to use a pressure washer outside my house, but there's no spigot nearby. I do have my tankless gas water heater nearby though, which has drain valves (both hot and cold). When I opened up the cold water drain valve cap (circled in red) and turned the valve above it, cold water came out. Can I hook up a garden hose to this and feed my pressure washer? I'll turn off the gas and the power to the heater when I do this just to be safe. Thank you. enter image description here

1 Answer 1


From you photo it also appears to also be the water source for the heater. As long as you can draw water without closing the water valve to the heater I see no reason why you cannot use hook up a garden hose to this and feed your pressure washer or possibly as a general purpose water outlet.

  • It would be wise to add a backflow preventer between the spigot and the hose.
    – John Canon
    Commented Apr 12, 2022 at 6:40

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