What Is Muriatic Acid? Cleaning Uses and Safety

A form of hydrochloric acid, muriatic acid is a powerful home cleaning tool

Cleaning off excess tile grout

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Masonry projects that use cement products, like mortar, concrete, and grout, can be messy. Muriatic acid is a sure way to clean masonry surfaces.

What Is Muriatic Acid?

Muriatic acid is a powerful and corrosive acidic liquid made from hydrochloric acid, water, and other trace minerals.

This product is a very strong acid that will clean dried cement products off stones, bricks, and other masonry surfaces.

Muriatic Acid vs. Hydrochloric Acid

Muriatic acid is also known as hydrochloric acid and the two terms are frequently used interchangeably. However, there is a slight difference between muriatic acid and hydrochloric acid. Muriatic acid is a diluted form of hydrochloric acid. It also includes some impurities (including traces of iron) which makes it a yellow color compared to hydrochloric acid's colorless or very slight yellow tinge.

Muriatic Acid Uses in the Home

There are numerous cleaning uses for muriatic acid at home. Muriatic acid comes in different concentrations so it's best to check the label to make sure the concentration you are buying is appropriate for the task. Cautiously use corrosive muriatic acid as a last resort in the home for the following tasks:

  • To remove stains (including embedded oil stains) and mold from masonry and concrete (even in basements)
  • To remove stains and mold from tiled or concrete swimming pool surfaces
  • To remove rust from stainless steel
  • To clean and prep masonry for painting by removing efflorescence (a white crystalline coating)
  • To clean extremely stained shower and floor tile and grout (though this is best left to professional tile and grout cleaners)
  • To clear extremely clogged shower drains (this is also best left to professional plumbers)

Click Play for Muriatic Acid Safety Tips

Use Caution

While this is a very capable cleaning agent, it is also a very dangerous product and extreme caution must be used when cleaning with muriatic acid. If the proper safety precautions are not followed, severe injury can result.

However, with the proper precautions, muriatic acid can be used as a highly successful cleaner. Many masons use it at the end of almost every job that involves a stone wall, ​patio, landscape steps, or any other hardscape made with mortar or concrete. Follow the important tips below and you can use muriatic acid safely and effectively.


You can try using distilled white vinegar (5 percent acetic acid) instead of muriatic acid to clean rust off of stainless steel. It may take longer to do the job than muriatic acid, but vinegar is a less toxic ingredient, and you usually won't need to use vinegar with a higher percentage of acetic acid for rust removal.

Tips for Using Muriatic Acid Safely

  1. Keep it away from children: Do not let kids anywhere near this stuff.
  2. Always wear proper safety gear: You need thick rubber gloves, a respirator, safety glasses, a long sleeve shirt, and pants that completely cover your legs. This cleaner can stain your clothes, so wear something that you do not mind getting dirty.
  3. Be very careful with splashes and spills on surrounding surfaces. The acid can cause permanent damage to wood, plastic, and other surfaces.
  4. Have a supply of clean water on hand: This cleaner is almost always diluted with water before being used for cleaning. Water is used to wet the surface before and after cleaning. Always have a running garden hose nearby.
  5. You need to dilute this cleaning product with water before cleaning any masonry surfaces. You'll need a plastic bucket, and you must always add the water to the bucket first. Then slowly pour the muriatic acid into the water. If you pour water into acid, you will set off a chemical reaction that causes the acid to heat up, aggressively bubble out of the bucket, and splatter onto you. In addition, do not get too close to the bucket when pouring the acid because the fumes are intense and can be painful if inhaled.
  6. Take your time and work slowly. If you rush, you are more apt to lose concentration and spill or splash the muriatic acid.

DIY Projects Using Muriatic Acid

Ready to roll up your sleeves and get to work? How about laying a tile patio? Those with some DIY experience should be able to do the job themselves. If you're looking for an easier DIY masonry project, try building a concrete patio.

Article Sources
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  1. Medical Management Guidelines for Hydrogen Chloride. Agency for Toxic Substances and Disease Registry.

  2. Safe Use of Acid Solution. UC Berkeley.