What Is Trisodium Phosphate?

Trisodium Phosphate

Lee Wallender

Imagine a cleaner that cuts through the worst of stains, including mold, grease, and soot. It has no additives, no fragrance, no bleach or ammonia. This cleaner is very cheap and mixes up in minutes with hot water. Its shelf life is years and it has a proven track record of cleaning stubborn, grimy areas around the home. Yet it's not a product without controversy, and many states even ban it outright. This product is called trisodium phosphate and it just might be the heavy-duty cleaner you need for projects around the home such as painting or cleaning soot from chimneys.

What Is Trisodium Phosphate (TSP)?

Trisodium phosphate, commonly called TSP, is a packaged, blended cleaning product consisting of 75- to 80-percent trisodium phosphate and 20 to 25 percent sodium carbonate. It usually comes in the form of an odorless dry powder that must be thoroughly mixed into hot water to form a mostly clear solution, though slightly cloudy. Applied with sponges or scrub brushes, TSP is an effective, heavy-duty cleaner for problem areas around the house that may be sooty, greasy, or dirty. TSP is often used by painters to ensure that the surface will be clean, dust-free, and able to take the paint.

How to Use TSP

Before using TSP, you will need a clean bucket, clean sponge, waterproof gloves, eye and skin protection, and access to hot water.

  1. Wear eye protection, long sleeves, and waterproof gloves.
  2. Protect areas not being cleaned with plastic.
  3. Mix 1/2-cup of TSP per 2 gallons of water for heavy-duty cleaning or 1/4-cup of TSP per 2 gallons of water for household cleaning. Make sure that the water is hot to allow the TSP to become soluble.
  4. Squeeze the sponge dry.
  5. Clean the surface from the bottom upward.
  6. For difficult areas, a second cleaning with TSP is required.
  7. Rinse the cleaned area with warm water.

Pros

  • Inexpensive

  • Readily available in states that do allow its sale

  • Excellent cleaner for heavy-duty dirt and stains, especially grease

  • Can be mixed stronger or weaker, as needed

  • Long shelf life if kept dry

Cons

  • Not available in some states due to TSP bans

  • Will clump if it is not kept dry or free of humid conditions

  • Will stain some surfaces if precaution is not taken

  • Can irritate the skin

Working Safely With TSP

TSP is considered to be a stable, non-flammable, non-toxic cleaning product. Still, TSP requires care when you work with it. Always use waterproof gloves with touching TSP. Wear full skin protection, including long sleeves and long pants. Both TSP dry powder and in mixed form can irritate the skin.

Warning

TSP can darken or stain some materials. Keep TSP away from aluminum, as well as other metals, when the TSP solution is at its hottest. Paints that have a glossy sheen may lose their sheen if they come into contact with TSP. Hardwoods like oak and mahogany may darken if they are cleaned with TSP.

What to Clean With TSP

TSP Bans and Availability

TSP has long been the go-to cleaning product for most home improvement-related projects. However, since 2010, states have increasingly started to ban household cleaning products that contain phosphates as this chemical has been linked to water-fouling and toxic algae growth that can kill aquatic wildlife.

Dishwasher detergents containing phosphates are banned in all 50 states, and laundry detergents are banned in a majority of states. The movement toward banning phosphates includes TSP in many states. For retailers offering TSP in states with bans, the penalty can be high. In one case, a New York State home center was leveled a hefty fine after an administrative error inadvertently placed a few boxes of TSP on that retailer's shelves.

TSP Substitutes

Due to bans on TSP, as well as general concerns about the environment, some manufacturers offer TSP substitutes.

Free of phosphates, these substitutes usually come in fluid form for easier mixing with water and work comparable to TSP. Safe for cleaning aluminum, these solutions will not harm vegetation if you are using them for outdoor cleaning.

Another benefit of these phosphate-free cleaners over TSP is that they do not require rinsing after they have been applied to the surface.