Can You Use Bleach In A Pressure Washer?

It seems like a simple question doesn’t it? Can you use bleach in a pressure washer? The simple answer is yes, but only under certain conditions. Let’s take a closer look and see what the experts advise. Many people say you shouldn’t use bleach in a pressure washer, they quote many reasons why it’s wrong to do so and make many valid points.

Let’s start at what the pressure washer makers say, and take things from there.

Why Using Bleach In A Pressure Washer Can Void Your Guarantee

Most reputable pressure washer manufacturers state in their user manuals that using bleach in their pressure washer can void your guarantee. This is due to the chemical composition of bleach. Bleach is made from a group of oxidizers that break down cell membranes and damage cell proteins.

This makes it effective at cleaning away mould and bacteria but also effective at breaking down any organic compound. Why is that a problem? Because the washers that are used to seal the water pipes and pump in your pressure washer are made from rubber. The bleach actually damages the rubber seals causing leaks and damage to the internal components of the pressure washer.

Not only can bleach damage rubber washers, but it can also cause metals to corrode. Causing even more potential damage to the pressure washer. So you can see why they’re so anti-bleach.

How To Use Bleach In A Pressure Washer Safely

We’ve just seen the effects of bleach on the working parts of a pressure washer and just how much damage it can cause. But there are a couple of ways to use bleach in a pressure washer without causing too much damage. The first is known in the trade as down-streaming.

What Is Down-Streaming?

To use bleach safely in a pressure washer you need to purchase a downstream injector, these are relatively inexpensive and can be picked up for around £20. You attach the downstream connector to the high-pressure hose connector on the unloader valve.  It works by introducing the bleach into the water downstream of the water pump.

This protects the pump and washers from corrosion by the bleach and allows you to use bleach to clean away mould etc.  The other end of the downstream connector has a small filter attached to the hose, this end is placed into a bucket containing the bleach (diluted to the appropriate level) and is sucked up through the hose.

Using A Nozzle Attachment For Applying Bleach

The second way is using a nozzle attachment with a soap tip. This can also be connected to a lancer with a bottle and use a bleach and water mixture in this. As the lance and bottle are connected right at the end of the water system there is even less risk from bleach damage to the pressure washer.

Personal Safety

Remember bleach is indiscriminate, it will harm you just as much as any other organic material. Always wear protective clothing, goggles, mask and gloves when using a pressure washer with bleach.

Pets And Plants

Bleach can seriously harm your pets if they come into contact with it or consume it.  Due to the way bleach works it can damage or even kill plants, be aware of the overspray and runoff.

Damage To Buildings

If you plan on using bleach to pressure wash your roof, be mindful of any rubber seals to skylights etc. Bleach will damage any organic surface and can also leave streak stains on tiles, concrete etc.

Pressure Washer After Care

After using your pressure washer with bleach always run through a few minutes of just water to clear the system of any bleach residue.

What Is The Correct Mixture Of Bleach And Water?

It is recommended that the bleach to water ratio is 4 to 1, with 4 times the amount of water to bleach. Never use neat bleach as this is very corrosive and dangerous to use.

How To Pressure Wash Using Bleach

If you decide you need the cleaning power of bleach, follow this step by step guide to ensure you use it safely.

1. Mix the solution
   In a container mix 1 part bleach to 4 parts water and stir.
2. Check your pressure washer
   Inspect the hoses for kinks, check filters, straighten and clean respectively.
3. Start the pressure washer
   Run through your usual start-up regime and make sure your pressure washer is working correctly.
4. Attach soap tip
   Connect the lance and soap tip and fill the container with the bleach solution.
5. Keep pressure low
   Always use low pressure when using bleach this will allow the bleach mixture to evenly coat the surface you are cleaning.
6. Clean the pressure washer
   When you’ve finished washing all the surfaces required with bleach, run clear water through the pressure washer to remove all traces of bleach from the system.

What Will Bleach Clean When Using  A Pressure Washer?

Firstly, bleach is not a cleaning agent, it’s a disinfectant. So if it’s just general dirt and stains you want to clean, bleach is the wrong choice. Bleach is effective against mould, mildew, moss and algae, and can be used to kill weeds too. But care must be taken at all times.

Also, pressure washer manufacturers have made perfectly good alternative detergents that are safer to use, for you, your pressure washer and the environment. 

The Bottom Line

The simple answer to the question can you use bleach in a pressure washer is yes but it’s not recommended. In short, bleach can damage:

•  The internal workings of your pressure washer
•  Your fixtures and fittings
• Your plants
• Your pets
• Your person
• The environment

Plus there are many safe detergents that can be used in a pressure washer that will work just as well on many surfaces.

Frequently Asked Questions