Guide · Couplers, adapters and swivels
Pressure washer water inlet fittings
The inlet is the low-pressure garden-hose side. Its fittings, the inlet filter, and the supply temperature, hose length and flow limits makers set.
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Short answer
The water inlet is the low-pressure side, where a garden hose joins the machine. Its fittings are not rated for the high-pressure outlet, so never move them there. Before buying inlet parts, check the inlet filter and the maker's supply limits: water temperature, supply hose size and length, and flow.
Garden-hose thread
Dixon lists 3/4 in garden hose thread (GHT) as 1.0625 in male outside diameter with 11-1/2 threads per inch.[1] That is a coarse inch thread, unlike the metric M22 on the high-pressure side.
The US standard for hose coupling threads is ASME B1.20.7, which covers threads for hose couplings, valves, nozzles and other fittings used directly with hose, in sizes from 1/2 in to 4 in.[2] The ASME page itself does not use the words "garden hose thread" or "GHT".
GHT is not pipe thread. Dixon states that female NPT is not available on hose swivel nuts.[1] A hose swivel and a pipe fitting can look close and still not seal.
Inlet quick connects stay at the inlet
Kärcher's 2.645-221.0 is a garden hose quick connect set for the pressure washer's water inlet, and Kärcher says it cannot be used on the high-pressure outlet.[3] It has three pieces: a garden-hose connector, an inlet connector for Kärcher electric washers, and a connector that converts the threaded inlet on Kärcher gas washers to quick connect.[3] Kärcher's page does not say which piece goes with which model, so check your manual.
The same logic applies to any garden-hose fitting: it is built for supply pressure, not pump output.
Supply limits makers set
Inlet limits are per model and per manual. Three examples:
| Maker and document | Water temperature | Supply hose | Flow and pressure |
|---|---|---|---|
| Sun Joe SPX3000 manual (MR12) | 104°F (40°C) maximum; never a hot water supply | Not stated in our source | Not stated in our source |
| Generac manual (0L5053, SpeedWash line) | Below 100°F | No longer than 50 ft | At least 3.8 GPM at 30 PSI or more |
| Champion 100384 manual | See the manual | 5/8 in or larger | Not stated in our source |
Sources: Sun Joe's manual limits inlet water to 104°F and says the machine must never be connected to a hot water supply.[4] Generac's manual requires water below 100°F, a supply hose no longer than 50 ft, and at least 3.8 GPM at no less than 30 PSI.[5] Champion's 100384 manual recommends a 5/8 in or larger garden hose and lists a too-small garden hose and a restricted supply among causes of low or fluctuating pressure.[6]
Where a manual sets a cold-water limit, a hot-rated hose further down the chain does not change that.
See the Generac SpeedWash G0079000 and Champion 100384 pages for their full specs.
The inlet filter
The inlet filter screens the incoming water before it reaches the pump. For a Kärcher washer with no pressure, Kärcher's FAQ lists owner checks that include removing and cleaning the water-inlet filter and checking that the right accessories are being used.[7] Champion also lists a clogged inlet filter as a cause of low or fluctuating pressure.[6]
Check the filter before you buy a new inlet fitting or hose to fix low pressure. Do it with the machine off and the water shut off.
Backflow preventers
Kärcher describes a backflow preventer as a device that stops detergent from getting into the water system.[7] That is Kärcher's wording only, for its own machines. We give no plumbing advice: follow your machine's manual and your local plumbing rules on what goes between the faucet and the inlet.
Inlet parts
Picks that fit1 product
This is Westinghouse's own quick-connect kit for its machines. Choose it only if Westinghouse lists your model, and use each piece only at the joint Westinghouse names for it; read the pieces and any rating on Westinghouse's listing, since we found no verified rating.
More on choosing
On Amazon, check that 'Ships from / Sold by' shows Amazon.com or the brand.
Westinghouse's larger quick-connect kit
Westinghouse WPWFIT3KIT 6‑piece quick-connect kit for garden hose and M22‑14 mm hose/gun, brass
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Questions
What size is a pressure washer water inlet?
Most take a garden hose. Dixon lists 3/4 in garden hose thread as 1.0625 in male outside diameter with 11-1/2 threads per inch. Some brands add their own inlet quick connect, so check your manual.[1]
Can I connect a pressure washer to hot water?
Not the machines in our sources. Sun Joe's SPX3000 manual limits inlet water to 104°F and says never to connect a hot water supply; Generac's manual requires water below 100°F.[4][5]