There are two hoses on a pressure washer: the high-pressure hose that carries water to the gun, and the water hose – often called the supply hose or garden hose – that feeds water into the pump. A water hose for power washer is the supply line, and while it is lower pressure and less talked about than the high-pressure hose, it is just as important. If the supply hose does not deliver enough water, the pump starves and can be destroyed. This guide explains how to choose the right supply hose and how to avoid common mistakes.
Supply hoses are standard garden hoses used to feed water from a spigot to the pump inlet. They are not high-pressure hoses. But they must deliver adequate flow (gpm) to match the pressure washer’s demand. A kinked, too-thin, or damaged supply hose starves the pump and causes cavitation.
Choosing a Supply Hose
| Feature | What to Look For | Why It Matters |
|---|---|---|
| Diameter | 5/8 inch or 3/4 inch | Larger diameter delivers more flow |
| Length | As short as practical | Long hoses reduce flow/pressure |
| Material | Durable, kink-resistant | Prevents flow restriction |
| Fittings | Standard garden thread | Matches pump inlet and spigot |
| Condition | No leaks or cracks | Maintains supply pressure |
For high-flow pressure washers (4+ gpm), use a 3/4 inch hose and keep it short. A 1/2 inch hose on a high-flow machine will restrict supply and starve the pump.
Do You Need a Special Hose?
- Standard garden hose. Works for most machines if it delivers enough flow.
- Reinforced supply hose. Better for high-flow machines and long runs.
- Short high-flow hose. Ideal for machines needing 4+ gpm.
You do not need a high-pressure hose for the supply side – garden hose pressure is much lower than the washer’s output. You just need enough flow.
Common Mistakes
- Using too-small diameter. Restricts flow and starves the pump.
- Using too-long hose. Reduces flow and pressure.
- Kinked hose. Stops flow and damages the pump.
- Leaking connections. Reduce supply pressure and flow.
- Adding screens/filters incorrectly. A clogged inlet filter restricts flow.
- Confusing hose types. Never use the supply hose as a high-pressure hose.
Frequently Asked Questions
Can I use a regular garden hose as a water hose for a power washer?
Yes, as long as it delivers adequate flow (gpm) and is in good condition. For high-flow machines, use a larger diameter (3/4 inch) and keep it short.
What size water hose do I need?
5/8 inch minimum for most machines; 3/4 inch for high-flow (4+ gpm) machines. Keep it as short as practical to maintain flow.
Why is my pressure washer losing pressure?
Common causes include an undersized or kinked supply hose, a clogged inlet filter, or a low-flow water source. Check the supply side first.
Can I use a high-pressure hose on the supply side?
You can, but it is unnecessary and more expensive. A garden hose is fine as long as it delivers enough flow.
The Bottom Line
The water hose for a power washer is the supply line that feeds the pump. Choose the right diameter for your machine’s flow, keep it short and kink-free, and ensure all connections are tight. An inadequate supply hose starves the pump and causes damage – so match it to your washer’s gpm and keep it in good condition.