What Is Trisodium Phosphate (TSP)?

Pros and Cons, Cleaning With TSP, and Safety Tips

Trisodium Phosphate

Lee Wallender

Imagine a cleaner called trisodium phosphate with many uses 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, greasy areas around the home. Yet, it's not a product without controversy, and many states even ban it outright.

Trisodium phosphate, or TSP, might be the heavy-duty cleaner you need for projects around the home such as painting or cleaning soot from chimneys and cleaning mildew and mold behind refrigerators and kitchen sinks. As for areas around the country that have banned TSP, a substitute that works nearly as well is available.

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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 is typically inexpensive and 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 to surfaces 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, such as walls or cabinets in need of painting.

Though bans on phosphates are in effect in many communities, TSP is still legal in many areas. It's often favored by contractors and painters to ensure that the surface will be clean, dust-free, and able to accept the paint. However, phosphate-free substitutes to TSP are also available nearly everywhere.

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

  • TSP substitutes are available

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 eyes and skin

  • Can damage glass and mirrors and darken aluminum

  • Requires extreme care when using

Personal Safety and Environmental Considerations

Trisodium phosphate is a safe cleaner if you use it properly. Trisodium phosphate is harmful and toxic if used incorrectly because it 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. Keep TSP away from glossy surfaces.

TSP is known to harm vegetation and grass according to product safety data sheets. Since 2010, states around the country 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 deplete oxygen levels in the water and kill aquatic wildlife and aquatic plants.

Trisodium Phosphate Alternatives

Due to bans on TSP, as well as general concerns about the environment, some manufacturers offer TSP substitutes and you can also find your own.

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. Here's a list of alternatives to TSP:

  • Borax: Though TSP and borax are not the same, they can both be used to clean and cut through surface grease.
  • Dawn: You can use the original blue Dawn dish detergent instead of TSP to cut through surface grease.
  • Pressure-washing: This 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.

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

Equipment/Tools

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

Materials

  • Trisodium phosphate (TSP)
  • Hot water

How to Clean With Trisodium Phosphate (TSP)

  1. Prepare Yourself and Work Area

    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.

  2. Mix TSP Solution

    The correct trisodium phosphate formula is a mix of 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.

  3. 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.

  4. Clean Surface With TSP

    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.

  5. Rinse Surface Thoroughly

    Rinse the cleaned area with cool 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.

  6. Clean Surface Again With TSP

    For difficult areas, a second cleaning with TSP is required. Mix up another bucket with fresh, warm water and TSP and clean with this new solution. Rinse with a fresh bucket of cool water.

Tips For Cleaning With Trisodium Phosphate (TSP)

  • If you're not accustomed to rinsing surfaces after washing them down with a cleaning solution, this step is absolutely necessary with TSP. TSP will always leave a white film behind if not rinsed.
  • For problem surfaces or for mold and mildew, add some chlorine bleach to the TSP mix.
  • When you first mix up the TSP solution, it should have a cloudy, milky appearance but it should not be solid white.
  • Be especially careful of using TSP around glass, mirrors, and porcelain or ceramic tile. The mild acids in the TSP can etch the surface.

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

Tip

TSP is often used to de-gloss painted surfaces that need another coat of paint. Just be sure to thoroughly rinse the TSP with fresh water and wipe it down with a tack cloth.

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, 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, as a few major home centers have already experienced.

Article Sources
The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. The Unintended Consequences of Household Phosphate Bars. Iowa State University

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

  3. Phosphorus. EPA.