Can You Use Laundry Detergent in a Pressure Washer

Can You Use Laundry Detergent in a Pressure Washer

You’ve probably heard of people using all sorts of DIY pressure washer detergents to clean the surfaces outside of their home, and one of the most commonly used is laundry detergent, but just because your neighbor does it doesn’t mean you should.

So, can you use laundry detergent in a pressure washer? Yes, you can use laundry detergent in a pressure washer as long as the detergent is completely dissolved, it is a downstream pressure washer, and you follow proper pressure washer maintenance practices.

In this article, we will discuss the benefits of using laundry detergent in a pressure washer, why you might want to avoid it, and how to dilute it for effective use.

The Benefits of Using Laundry Detergent in a Pressure Washer

The Benefits of Using Laundry Detergent in a Pressure Washer

Many homeowners who make use of pressure washers for their outdoor cleaning find that laundry detergent works wonders for tasks like cleaning the siding of your home, concrete, or asphalt. Here are some of the reasons you might choose laundry detergent over a pre-mixed pressure washer detergent.

  • You have it at home. No need to travel to your local home improvement store to pick up cleaners. No need to store an extra bottle of cleaners in your garage or shed.
  • It sticks well to surfaces. Laundry detergent seems to have a sticking power that other DIY soaps don’t have.
  • It cleans well. Most laundry detergents are powerful. They have to get nasty stains, grease, and sweat out of clothes, and they will work nearly as well on the surfaces you’re pressure washing.
  • It is fairly gentle. Even though laundry detergent is powerful, it also has to be gentle so that it doesn’t destroy delicate fabrics. It won’t be too harsh for most applications.
  • It also rinses away easily. Laundry detergent needs to rinse out of clothes, and so it will also rinse off of the surfaces you’re cleaning easier than some other methods. You’ll be less likely to be left with a soapy residue. Of course, this is only true if you dilute the detergent appropriately.
  • It doesn’t get excessively sudsy. As long as you’re using the right amount of soap, using laundry detergent in your pressure washer won’t leave you with a sudsy mess as dish soap does. 

As you can see, laundry detergent works well as a cleaner for most pressure washing situations. You might be thinking there is no reason to avoid using it, but there is a downside to everything.

The Downside of Using Laundry Detergent in a Pressure Washer

The Downside of Using Laundry Detergent in a Pressure Washer

Now laundry detergent isn’t the perfect detergent for a pressure washer. (there’s a reason the pros mix their own cleaning fluids!) Before using laundry detergent in your pressure washer, you should take these disadvantages into account.

You Could Damage Your Pressure Washer

No matter what type of pressure washer you are using, if you run a cleaning fluid through it that wasn’t designed for use in a pressure washer, you run the risk of causing damage to all parts of the pressure washer that the soap runs through.

This is more of a risk for pressure washers with upstream injectors. So you will want to be extra careful if you have an upstream injector.

What’s the Difference Between an Upstream Injector and a Downstream Injector?

If all this talk of upstream and downstream has you scratching your head, don’t worry. It’s not that complicated.

  • Upstream injector: The cleaning chemicals will run through the pump of the pressure washer, which means that there is more potential for damage. Many recommend only running water through your pressure washer if you have an upstream injector.
  • Downstream injector: The cleaning chemicals are added into the water after the pump, which means the chemicals cannot damage your pump, although it can still cause issues in other parts of your pressure washer.

But how do you know if you have an upstream injector or a downstream injector? The easiest way is to check your user’s manual. It will leave no room for doubt.

To avoid damaging your pressure washer with your chosen soap, you could install a downstream injector on most pressure washers using a downstream injector kit. You could also simply apply the soap separately with a sprayer or a brush, even if it is a little more work.

Laundry Detergent Often Contains Phosphates

Phosphates are used in many detergents because of their ability to balance the pH of a solution, soften hard water, and dissolve in water, but it is becoming clear that dumping too much phosphate into the environment can be a bad thing.

  • Phosphates aren’t good for the environment. They can cause problems for local lakes and streams because it increases the number of algae, which reduces the amount of oxygen in the water, and other living things need this oxygen. Basically, it upsets local ecosystems. And remember, the water that runs into your storm drain at the curb is usually directed toward local streams. 
  • Phosphates aren’t great for your pressure washer. They may cause damage if they dry inside any part of your pressure washer.

So, if you are going to use laundry detergent in your pressure washer, it is best to stick to phosphate-free laundry detergent.

Don’t Use Laundry Detergent For Cleaning Your Car

The only cleaner you should use on your car is a cleaner that is meant to be used on a car. Seriously!

Laundry detergent is a powerful cleaner, and it will clean the shine right off your car if you use it for regular car cleanings, and it doesn’t just look nice. It protects your car’s paint job. So, protect your investment by using only specially formulated cleaners on your car.

There are many inexpensive car washing soaps meant to be used with a pressure washer, and there is really no reason not to go with one of them.

How to Dilute Laundry Detergent For a Pressure Washer

How to Dilute Laundry Detergent For a Pressure Washer

How much laundry detergent you use is going to depend on the method you decided to use with your pressure washer. 

  • If you’re going to be running the detergent thought your downstream injector, mix about a cup of detergent into a gallon of water. This might seem like a lot, but the downstream injector will further dilute the mixture.
  • If you’re going to apply the mixture separately, mix a quarter of a cup of detergent with a gallon of water. You can always mix in a little more if it isn’t strong enough, but you don’t want to overuse the detergent and have a hard time rinsing later.
  • If you are going to running the detergent through an upstream injector, reconsider. Most people do not recommend this. If you still plan to do it against our recommendations, you will need to dilute it. Mix a quarter cup of detergent per gallon of water or less.

It is best to allow the soap to sit for about 10 minutes to give it time to work on the dirt and grime. Rinsing immediately will not give you the best results.

When you are done using your pressure washer, be sure to perform your normal post-wash maintenance tasks. Pay special attention to rinsing all detergent from the pressure washer. Run clean water through the pressure washer on a low-pressure setting for about 3 minutes.

If laundry detergent dries inside the pressure washer, you could end up with a damaged machine.

Final Thoughts

Can You Use Laundry Detergent in a Pressure Washer

To be on the safe side, it is best to use phosphate-free laundry detergent in a separate sprayer from your pressure washer or apply your soapy solution with a brush. This way, you aren’t running the chemicals through your pressure washer. If you have a downstream injector, there is less of a risk of damaging your pressure washer, however, and many choose to use laundry detergent in this set up without an issue.

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