Will Bleach Remove Rust from Concrete? (No, Here’s What to Do Instead)

Will Bleach Remove Rust from Concrete? (No, Here’s What to Do Instead)

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If you have rust stains on your concrete driveway or patio, you probably hate how they look. No, that orange-reddish-brown stain just doesn’t look nice, plus it’s not good for the concrete either.

If you have some household bleach laying around, you might think that pouring it on the rust stain will remove it. Unfortunately, this is not really the case at all. Let’s figure out what bleach is, why it won’t remove rust stains from concrete, and what to do instead.

What Is Bleach and Will It Remove Rust Stains From Concrete?

Bleach or household bleach is generally used as a powerful cleaning product and disinfectant agent, and often as a mold killer as well. Bleach is made out of water, salt, and sodium hypochlorite, which is otherwise known as liquid chlorine.

Your average household bleach contains about 5% liquid chlorine. Chlorine is a very powerful disinfectant that has the ability to kill a wide variety of viruses and bacteria, which is why it is used in drinking water and swimming pools alike.

This is why chlorine bleach makes for such an effective stain remover too. So, chlorine bleach is able to kill bacteria and get rid of stains in clothing but does it have the ability to break down rust? The short answer here is no, bleach will not remove rust stains from concrete.

2 Reasons Why Bleach Won’t Remove Rust Stains From Concrete

Now that we know why bleach does not remove rust stains from concrete, let’s figure out exactly why this is the case.

1. A Lack of Penetration

One of the main reasons that chlorine bleach will not remove rust stains from concrete has to do with penetration issues, which means that the bleach cannot penetrate all the way down into the concrete to remove all of the rust. Concrete is very porous, which means that any rust stains aren’t just going to sit neatly on the surface.

Those rust stains can be pretty deep down in the concrete. The issue with chlorine bleach is that it just won’t penetrate that far down into the porous concrete. While it may look like bleach removes rust stains from concrete at a quick glance, if you look closer, you will notice that there is still plenty of rust left over, especially in the porous sections.

2. It Just Removes the Color

The other reason that chlorine bleach does not remove rust stains from concrete is that it doesn’t actually break down and dissolve the rust. There are plenty of rust removers out there that contain strong acids that have the ability to literally dissolve rust and penetrate deep down into the concrete.

Bleach doesn’t contain any acids and therefore won’t dissolve rust. Sure, bleach may remove some of that reddish-brown coloration, but it’s just that, removal of color, not of the actual rust. So, while the rust may have lost its color due to the bleach, it’s still there.

How to Remove Rust Stains From Concrete Without Bleach

So, if bleach won’t get rust stains off of concrete, then what can you use to do so?

Well, one of the most cost-effective methods of removing rust from concrete is by using a combination of baking soda and laundry detergent. The baking soda creates a basic or alkaline solution that does dissolve rust, with the laundry detergent capturing the dissolved rust. This is a good method for small and minor stains.

Of course, acids are always a good way to go for dissolving rust stains, and if you want to use household products that you already have laying around, so you don’t have to spend much money, then both lemon juice and vinegar work quite well, with vinegar being the stronger of the two. That said, these methods work best for light to moderate rust stains, but usually won’t do well when it comes to heavy and widespread rust stains.

If you are looking for something more powerful, something that contains plenty of acids and is well known as being an effective remover of calcium, lime, and rust, then some CLR will do the trick. This is a household cleaner that will quickly dissolve rust, and it works for some pretty heavy stains too. That said, CLR can’t be used on certain types of concrete, and it may stain concrete too, so be careful when using it.

Another product that will effectively remove rust from concrete is WD-40. The regular version of WD-40 is ideal for removing moderate rust stains. However, if you have big rust stains, using WD-40 Specialist Rust Remover is recommended. It’s not cheap, but it does work very well. Just keep in mind that if you are using regular WD-40, you will need a degreasing agent once the rust has been loosened, as WD-40 is a lubricant, so removing it from the concrete can be a challenge in itself.

For more details, read my article about how to remove rust from concrete.

Mistakes to Avoid, Tips & Tricks

Let’s quickly go over some tips and tricks to help make removing rust stains from concrete as easy and fast as possible:

  • Whatever rust removal substance you are using, always make sure to spot test a small area first, just to make sure it doesn’t stain.
  • Unless you are using vinegar, lemon juice, or baking soda, you do generally want to wear gloves to protect your hands. Many of the acids that can remove rust from concrete are quite corrosive.
  • If you are using a professional rust removal product or acid, always follow the directions on the label, especially when it comes to safety precautions.

Summary

As you can see, although bleach is not ideal for removing rust stains from concrete, there are plenty of other substances and products that can get the job done.