pH of cleaning products: a chart of common chemicals and which pH cleans which soil

What is the pH scale for cleaning chemicals?

The pH scale measures how acidic or alkaline a water-based solution is, from 0 to 14, with 7 neutral. Numbers below 7 are acidic and numbers above 7 are alkaline (also called basic), as the U.S. Geological Survey explains on its pH and water page. For a cleaner, pH is the single best predictor of what a product will dissolve and what it will damage.

The scale is logarithmic. Each whole number is a tenfold change: pH 5 is ten times more acidic than pH 6, and pH 13 is a hundred times more alkaline than pH 11. That is why an oven cleaner at 13 to 14 burns skin while a baking soda paste at about 8 is safe to touch, even though both sit on the “alkaline” side.

The scale in cleaning terms

Products are formulated, not just measured. Surfactants, solvents and builders do a lot of the work, so two cleaners at pH 10 can perform very differently. pH tells you the category and the risk; the label tells you the job.

pH chart of common cleaning products

The chart below gives the pH of the common chemicals and product types a cleaning company meets. Where a figure comes from a measured solution of the active ingredient (PubChem, the chemistry database run by the National Institutes of Health), that is noted; branded products vary with concentration and additives, so treat the ranges as typical, and read the safety data sheet for the exact product you carry.

Two notes on the chart. Bleach sits where it does partly by design: Clorox explains that its bleach contains at least 5% sodium hypochlorite plus a little sodium hydroxide and sodium carbonate to buffer the solution and keep it stable. And “ammonia” on a store shelf is ammonia dissolved in water (ammonium hydroxide) at up to about 10%, which PubChem gives for household use, so household ammonia lands around 11.6 to 12.

Which pH removes which kind of soil?

Use the opposite of the soil: acids dissolve mineral deposits, alkalis break down organic soils, and neutral cleaners handle everything that is just dirt. Picking the right side of the scale is most of the difference between a surface that wipes clean and one that needs scrubbing.

A practical rule for training: if it is white and crusty, think acid; if it is greasy or sticky, think alkali; if you are not sure, start neutral and work outward. A cleaner who learns that one sentence stops reaching for a degreaser on soap scum, which is a common mismatch in bathrooms.

Where pH does not help

Disinfection is not a pH question. A quat disinfectant can be near neutral and still kill what its label says, and a strongly alkaline degreaser kills very little. Choose a disinfectant by its EPA registration and contact time, not by pH, and clean the soil off first so the disinfectant can reach the surface.

Which surfaces are damaged by the wrong pH?

Natural stone, aluminum, waxed or oiled wood and some finishes are the surfaces most often damaged by the wrong pH. The damage is usually permanent and usually the cleaning company’s to pay for, so the surface list belongs in your training as much as the soil list.

• Marble, limestone, travertine, terrazzo. Acids etch them: vinegar, citrus cleaners and acidic bathroom sprays leave dull spots that need a stone professional to polish out. Use neutral or stone-specific cleaners only.
• Granite and quartz. Tougher, but strong alkalis and acids can dull sealers and some resins. Neutral is the safe default.
• Aluminum (window frames, some appliances, ladders). Strong alkalis such as oven cleaner and some degreasers darken and pit it.
• Hardwood and laminate. Alkaline cleaners can strip finish; acid residue can dull it. Neutral floor cleaner, barely damp.
• Grout. Repeated acid cleaning erodes cement grout; alkaline cleaners are usually safer for routine work, acids only for scale, and rinsed.
• Brass, copper, some chrome. Acids and ammonia can tarnish or spot plating.
• Painted and lacquered surfaces. Strong alkalis soften paint; keep oven cleaner off cabinet doors.

Test in a hidden corner before using any acid or strong alkali on a surface you have not cleaned before, and put “no acids on stone” on the client’s property notes so every cleaner sees it. Damage claims are expensive even when you are insured; the cleaning business insurance guide explains how deductibles work on property damage.

How dangerous are the extremes, and what should never be mixed?

Both ends of the scale burn. Strong acids and strong alkalis destroy skin and eye tissue on contact, and some combinations release toxic gas. The two rules that prevent almost every injury are: gloves and eye protection for anything below pH 3 or above pH 11, and never mix products.

Never mix

• Bleach with ammonia: releases toxic chloramine gases. Ammonia hides in some glass cleaners and in urine, so do not use bleach on a toilet or floor that has just been cleaned with an ammonia product, or on fresh pet accidents.
• Bleach with acids: releases chlorine gas. Acids include vinegar, toilet bowl cleaners, drain cleaners, rust removers and brick and concrete cleaners, as the Washington State Department of Health lists on its bleach mixing dangers page, which advises not to mix bleach with ammonia, acids or any other cleaner.
• Bleach with alcohol: the Northeastern safety sheet lists alcohols among bleach’s incompatibilities, forming chloroform and other irritants. Keep alcohol-based glass cleaner and bleach apart.
• Drain cleaners with anything, including other drain cleaners and water in the wrong order. Lye gels react with heat; follow the label exactly and never add a second product to a clogged drain.

Handling the extremes

• Oven and drain cleaners (pH 13 to 14): long gloves, eye protection, ventilation, and never spray near the face. Easy-Off’s own label says it contains sodium hydroxide, will burn eyes and skin, and to use only with adequate ventilation.
• Acid bowl cleaners (pH 0 to 2): gloves and goggles, apply under the rim and let it work, never scrub so it splashes, flush well, and never use on the bathroom floor.
• Bleach (pH 11 to 13): gloves, dilute per label, mix water first, fresh each day, and keep it away from every other bottle.
• Splash in the eye: rinse with clean water for 15 minutes and seek medical care; the SDS for each product gives the specific first aid.

Once you have employees, OSHA requires labels, safety data sheets and training for the hazardous chemicals they use. The chemical safety section of the cleaning business supplies list covers what the Hazard Communication Standard asks of a small cleaning company.

Why should neutral be your default product?

Neutral cleaners (pH about 6 to 8) handle most daily soil, are safe on almost every sealed surface, and are the hardest for a new cleaner to misuse. Build the kit around one neutral all-purpose cleaner and one neutral floor cleaner, then add one acid and one alkali for the jobs that need them.

A four-product pH kit

Oven cleaner and acid bowl cleaner are specialty products: carried by trained cleaners for add-on services, priced as add-ons, and kept out of the everyday caddy. The supplies list guide covers the full kit and what each item costs.

How do you test pH and teach it to cleaners?

Test with pH strips or a pocket pH meter when you need to know what is in a bottle, and teach pH with a one-page chart on the caddy lid rather than a chemistry lesson. Cleaners need to know three things: which side of the scale each bottle is on, which soils it is for, and what it must never touch.

Testing

• pH strips (0 to 14) are inexpensive and accurate to about one unit, enough to tell an acid from an alkali.
• A pocket meter is more precise; useful if you blend your own dilutions or want to confirm a floor is rinsed to neutral before applying finish.
• Test diluted product, not concentrate: dilution moves the pH toward 7, which is why a 1:64 degreaser is milder than the jug.
• Rinse water should test near neutral before you lay down wax or finish; an alkaline residue can cause finish failure.

A 15-minute training

1. Lay the kit out in pH order, acid to alkali. Say what each one removes.
2. Give the two rules: “white and crusty, acid; greasy and sticky, alkali.”
3. Give the surfaces list: no acids on stone, no strong alkalis on aluminum or paint.
4. Show the never-mix pairs and the rinse-between habit.
5. Test two bottles with strips so they see the numbers are real.

Put the chart on the checklist the cleaner uses on each job so it travels with them; the free cleaning checklist template has a supplies section for exactly this. This guide is general guidance; the product label and safety data sheet always take precedence, and some states regulate specific chemicals, so check yours.