The Pros and Cons of Cleaning with TSP

TSP is a powerful, tried-and-true cleaning agent, but it's so potent that you must be very careful when using it. Read on to learn its rewards and risks.

By Bob Vila | Updated Sep 28, 2020 11:29 AM

Cleaning with Trisodium Phosphate - TSP Cleaner


It wasn’t so long ago that trisodium phosphate (TSP) was a go-to choice for tough cleaning jobs, especially on exteriors. Diluted in water and applied often with a stiff scrub brush, it can remove stubborn grease stains and mold and mildew growth. In recent years, however, the popularity of TSP has waned. There are no complaints about its performance—TSP was and remains a highly effective cleaner. Rather, an increasing number of people are steering clear of cleaning with TSP simply because, due to its potency, working with the stuff can pose dangers to personal health and the environment.

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Here, we look at both the pros and the cons of working with a TSP cleaner, leaving you to decide whether or not it’s the right choice for you and your family, your home, and the situation at hand.

The Pros and Cons of Cleaning with TSP


Pros of Cleaning with TSP

  • Efficacy: There’s little doubt that TSP cleaner works great. In fact, it often succeeds where other solutions fail to do the trick with the most stubborn stains like grease and dirt.
  • Easy application: You might expect that using such a powerful cleaning agent would entail a complicated procedure, but once diluted, TSP can be applied simply with a brush or sponge, or via a sprayer.
  • Suitability for exterior surfaces: TSP works well—and without damage—on a variety of surfaces, including brick and stone, cement, wood, and roofing. If the surface is previously painted, you should expect to repaint after cleaning with TSP (see next).
  • Paint-stripping capabilities: So strong that it will peel old paint from a surface along with the stains, TSP is often used for cleaning surfaces in the course of preparation for painting, particularly for exteriors. It removes splintered or flaking leftover paint that may impede the bond of the new coat.
  • Mold and mildew treatment: One benefit of washing exteriors with TSP cleaner is that, when combined with household bleach, it eliminates mold and mildew.

These advantages made TSP especially popular for clearing oil stains from concrete driveways, preparing surfaces for paintstripping paint from masonry, removing creosote from fireplaces, washing decks, and cleaning exterior siding.

Pro tip: If you’re using TSP to clean siding, speed up the job with a power washer. Don’t own one? Rent the tool from your local home center. Doing so may set you back a few bucks, but you’ll save endless trips up and down the ladder.

The Pros and Cons of Cleaning with TSP


Cons of Cleaning with TSP

  • Toxicity: Being toxic, TSP must be handled with care. That means wearing the appropriate protective gear. T-shirts and shorts are a no-no. Instead, wear full-sleeve clothing in addition to gloves, glasses, and a respiratory mask. And if you’re going to be working indoors, you must adequately ventilate the area.
  • Danger to landscaping: If using TSP outdoors (especially if mixing it with bleach), use only as much TSP as you need and tightly control the runoff. Be sure to protect your landscaping. Choose a windless day for your project, and hose down any nearby plants, shrubs, or tree branches, both before and after the job.
  • Environmental concerns: TSP cleaner can also be bad news for the environment as a whole. If it ends up in lakes and streams, the phosphates trigger an overgrowth of algae that results in a depletion of oxygen levels in the water, which endangers fish and aquatic plant life.
  • Local regulations may limit use: You should also be aware that, given the drawbacks of TSP, some municipalities have either limited its use or banned its use altogether. Before starting your cleaning project, be sure to check local regulations. Also note that on the shelves of your local home center you may not find TSP, but TSP substitute instead. The latter is much safer to use, but most agree that it doesn’t clean as well as the real stuff.
  • Damage to certain surfaces: Avoid cleaning with TSP in the bathroom; it can damage metal, ceramic tile, grout, and glass. And as discussed above, it’s not suitable for painted surfaces.

An Alternative to Cleaning with TSP

If the cons give you pause and you wish to use another cleanser, consider this TSP substitute: borax. Also known as sodium borate, borax is a naturally-occurring mineral compound that will clean many of the same surfaces TSP has been used on for years, including mold- and mildew-stained areas—all without causing damage nearby plants. (See it in use in our tutorial for homemade deck cleaner.) Plus, you can pick up this powerful antimicrobial cleaning agent right in your grocery store’s cleaning aisle.