Can Pressure Washers Run without Water?

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If you have been the owner of a pressure washer for a while, you probably use it with water without giving a second thought. The owner’s manual tells you what to do, but what happens if you try to start the pressure washer up minus water? Is it even possible to start the machine and if it does, how long will it run?

Pressure washers should never be used without water. Water prevents the pump from overheating and also functions as a lubricant. Without water the pump will quickly wear out and possibly suffer permanent damage.

Why Pressure Washers Need Water to Start

Think for a second how a pressure washer operates. When you turn it on, the washer releases water in high volume and with pressure. It is many, many times more powerful than a garden hose so it is ideal for cleaning cars, vans, and large surfaces.

Pressure washers cannot clean without water, period. But not only that, it probably will not start without it either.

Even if you somehow get a pressure washer to run with no water, it will stop soon or malfunction at some point. Besides the cleaning part, water also keeps the pressure washer running smoothly.

As with any pump, the longer you run the hotter it gets. Water is able to keep the temperature down even when the pump runs. Even if you use the pressure washer for long stretches, the pump will maintain its temperature so it does not overheat.

When we think of pressure washers and water we think of cleaning. But water does a lot more than that as it is essential for running and maintaining the pump.

What Happens if a Pressure Washer Runs with No Water?

If you read the owner’s manual – and you should – water is necessary to run a pressure washer. But what if you forget or out of curiosity just want to find out what happens?

If you start a pressure washer without water, its pump will overheat. This can cause serious and likely permanent damage. Lack of water also means there will be nothing to lubricate the pump.

There are two things going against a heavy duty pump, overheating and wear and tear. When you turn on a pressure washer such as the Simpson Cleaning GX200 pressure washer, the pump drives water into the hose to the nozzle.


This tighter the nozzle, the higher the pressure. A typical pressure washer is 50 times more powerful than a garden hose. Think of how much force the pump exerts to perform to do this.

To keep this up, the pump must not overheat. That is where water comes in as it cools the area around the pump. Starting a pressure washer and running it will generate a lot of heat. By having water available at the onset, this can be avoided.

Now if you take out the water, the temperature will continue to rise. Keep using an overheated pump and it will break down eventually. Even worse, the damage can spread throughout the pressure washer.

A good analogy is that of an engine. You never let engines overheat because of the risk, and the same applies to pressure washer pumps.

Lack of Lubrication

Water functions as a lubricant for the pump. Without it, the pressure washer has to exert more effort, which generates friction.

The presence of water make things easier for the pump. To put it simply, lubricants reduce stress on the hardware, allowing them to run smoothly with less effort.

If you take out the water, friction increases. The pump expends more effort to run which increases wear and tear. If you have ever tried running a pump without lubricants, you know what difference it makes.

You can see what will occur when a pressure washer operates without water. In the short term, the pump will stall and stop. In the long term it is going to accelerate wear and tear.

Bottom line: do not forget to use water. You will end up with a faulty pressure washer with a lot of problems. Water is only one part as pressure washers also need oil to run.

Damaged Caused by Not Using Water

Wear and tear and overheating are two of the biggest problems if you start a pressure washer without any water. Aside from damaging the pump, other parts could suffer damage as well.

The pump is connected to other parts. Without any lubricant, the pump will be forced to work harder, which triggers a domino effect. Not only is the pump affected, but the motor as well.

The pump cannot turn without the motor. Lubrication makes it easy to turn the pump, but with no water, friction increases.

You can see where this is heading. The motor has to function harder to operate the pump. An overworked motor is going to wear out the seals, gaskets, rings and other parts.

You are going to end up with a defective pressure washer that can cost a lot of money to repair. In the worst case scenario you will have to buy a new one. As you can see there are a lot of issues that will come up. However you can avoid them by making sure there is water when you run the pressure washer.

How to Check for Signs of Damage

So now you know it is not a good idea to use a pressure washer without water. But what if you forgot? What if you already turned it on and just realized there is no water? Is it damaged already?

If you suddenly remembered there is no water, turn the pressure washer off right away. The next step is to add water to it. Follow your owner’s manual on how to properly add it.

Next, turn the machine on again. If you are lucky or have a quality built pressure washer – the WEN PW3200 is a good example – , there will be no damage. If water emerges from the nozzle then everything is fine.

If water does not come out, the pump and / or motor has been damaged. If the pressure washer starts and then stops, that is another sign of pump damage.

You have two choices, rebuild the motor and pump or buy a new one. If you are going to rebuild, new parts will be required. Unless you know how to do these things, you will need a specialist to do it for you. Either way it is going to be expensive. This is the reason why you must always us pressure washers correctly.

Image Credit: Pgdp123

Can Pressure Washers Run with Limited Amounts of Water?

Too much water can cause problems like leaving marks on cement but that is no reason not to start the pressure washer without it. Using little to no water can damage a pressure washer.

You must always the right amount of water as the manufacturer suggests. These are complex tools that require specific parts to run, and these parts will only work under certain conditions. One of these conditions is having enough water to start with.

If water does not come out of the pump, it means there is damage to the pump or motor. The good thing is you can avoid this with proper usage.

Frequently Asked Questions

How long can you run a pressure washer without water?

No more than five minutes. If you accidentally turn it on without any water, shut the motor immediately. Leaving the motor idling with no water will lead to overheating.

Can you use a pressure washer with a bucket of water?

Some models can use a bucket, but it requires a suction hose. Check the owner’s manual if it is possible.

Can I use a pressure washer with low pressure?

As long the pressure meets the minimum requirement, it will not be a problem. Most of them will run with as low as 20 psi.

What should I do if the pump or motor is overheating?

Shut the pressure washer off right away. Wait for the motor and pump to cool down. Restart it again with water and see if that works. If that fails, you need to rebuild or buy a new motor or pump