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 for painting or cleaning soot from chimneys or for cleaning mildew and mold behind refrigerators and kitchen sinks.


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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. TSP 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. Though bans on phosphates are in effect in many communities, TSP, where legal, is often favored by contractors and painters to ensure that the surface will be clean, dust-free, and able to take the paint. Phosphate-free substitutes to TSP are available.

  • 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

  • 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 eyes and skin

  • Can damage glass and mirrors and can darken aluminum

Safety Considerations

TSP is toxic and can cause eye and skin irritation and is harmful if swallowed. TSP requires care when you work with it. Always use eye protection and waterproof gloves when handling or cleaning with TSP. Also wear full skin protection, including long sleeves and long pants. Safety precautions apply to both dry and mixed or diluted forms of TSP.

Project Metrics

  • Working Time: 5 minutes for 10 square feet
  • Total Time: 15 minutes
  • Skill Level: Beginner
  • Material Cost: $5 to $10

What You Will Need


  • Sponge
  • Bucket
  • Latex or nitrile gloves
  • Eye protection


  • Trisodium phosphate (TSP)
  • Hot water

How to Clean With Trisodium Phosphate (TSP)


Wear eye protection, long sleeves, and waterproof gloves. Use plastic sheeting to protect areas of the home that are not being cleaned with the TSP.

Mix the Solution

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, as this allows the TSP to become soluble. Thus, wearing gloves not only helps to protect the skin but it allows you to handle hotter water than you could manage with bare hands.

Soak and Squeeze

With gloves on, soak the sponge in the water. Hold the sponge over the bucket and thoroughly squeeze it dry. A damp sponge is better than a wet sponge, since the wet sponge may leave tracks from drops of water.

Clean the Surface

Clean the surface from the bottom upward. Move the sponge in broad strokes to remove the worst of the debris. Again soak the sponge in the TSP solution and squeeze out, the more frequent, the better.

Clean Again

For difficult areas, a second cleaning with TSP is required. Rinse the cleaned area with warm water. Because TSP begins as a dry, white powder, it often can conclude as a dry, white powder on the surface after the water has dried. To combat this, make sure that you rinse the surfaces with a new sponge and a bucket that has been thoroughly rinsed out or even a new bucket.

What to Clean With TSP

  • Walls, ceiling, trim, and other woodwork before painting
  • Mold and mildew from decks
  • House siding
  • Soot on chimney mantels
  • Greasy stains and unidentifiable stains
  • Lead paint dust
  • Beams or joists in crawlspace
  • Mold in the home, before mold remediation
  • Kitchen walls near cook areas before painting
  • Behind refrigerators
  • Bathroom ceilings before painting

What Not to Clean With TSP

Though TSP can be used for a wide variety of surfaces, it cannot be used for all surfaces. TSP can darken or stain some materials, and it can etch glass and mirrors. 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. If you have any concerns about whether or not to use TSP on a particular surface, test a small amount in an inconspicuous area first, or use a substitute cleanser.

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.

Pressure-washing is another alternative to cleaning outside surfaces with TSP. With sufficient and well-calibrated water pressure, it is possible to clean tough areas with only the pressure of the water.

Article Sources
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  1. The Unintended Consequences of Household Phosphate Bars. Iowa State University

  2. National Center for Biotechnology Information. PubChem Compound Summary for CID 24243, Trisodium phosphatePubChem, 2005.