What is in a bottle of bleach, and which kind should I buy?
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Household chlorine bleach is sodium hypochlorite dissolved in water. CDC says most household bleach contains 5 to 9 percent sodium hypochlorite, and tells you not to use a bleach product for disinfecting if its percentage is outside that range or not stated. For disinfecting, buy regular, unscented bleach whose label carries an EPA registration number and disinfecting directions. Splashless and some laundry bleaches are not appropriate for disinfection, according to CDC. Bleach is strongly alkaline and corrosive to skin and eyes, and it must never be mixed with any other cleaner. This page explains what is in the bottle, how the product types differ, and how to handle and store it.
Sodium hypochlorite, alkali and a registration number
The Clorox Company's Safety Data Sheet for Clorox Regular Bleach2 lists sodium hypochlorite at 5 to 10 percent, with the exact figure withheld as a trade secret, and sodium hydroxide in its state right-to-know listing [1]. The pH is 12.1 [1]. Sources differ on the usual strength: Poison Control's chlorine gas article gives household bleach as typically 3 to 6 percent [7], CDC says 5 to 9 percent [4], and the Clorox sheet 5 to 10 percent [1]. This page follows CDC's range, because CDC's dilution is written for it; the figure that matters for your bottle is the one on its label. The product carries EPA Reg. No. 5813-111 [1], which means it is sold under an EPA pesticide registration with label directions for the uses EPA accepted.
Those three facts explain how bleach behaves:
- Sodium hypochlorite is the oxidizer that whitens, removes stains and, used as the label directs, disinfects.
- The high pH comes from the alkali. It is part of why bleach is corrosive to skin, and it is why acid is so dangerous with bleach: an acid lowers the pH and releases chlorine. The SDS for 5 percent acetic acid lists "bleach and other hypochlorites (release chlorine)" among its incompatible materials [2].
- The registration number is what allows a disinfecting claim. Under federal law, a claim that a product sanitizes, disinfects or sterilizes makes it a pesticide that must be registered [3].
Which bleach to buy
| Product type | What it is | Use it to disinfect? | Source |
|---|---|---|---|
| Regular unscented bleach with an EPA Reg. No. and disinfecting directions | 5 to 9 percent sodium hypochlorite | Yes, following the label or CDC's dilution | CDC [4]; Clorox SDS [1] |
| Concentrated bleach | Sold as stronger than regular; read the percentage | Only if the label gives disinfecting directions and the percentage is within CDC's 5 to 9 percent range; follow the label's dilution | CDC [4] |
| Splashless bleach | Formulated to splash less | No: CDC says it is "not appropriate for disinfection" | CDC [4] |
| Some laundry bleaches | Sold for whitening clothes | No, unless the label carries disinfecting directions; CDC names "some types of laundry bleach" as not appropriate | CDC [4] |
| Scented bleach | Bleach with fragrance | CDC specifies "regular unscented household bleach" for its dilution | CDC [4] |
| "Color-safe" bleach | Read the active ingredient | Only sodium hypochlorite as the active makes it chlorine bleach | See the oxygen bleach page |
| Bleach with no percentage on the label | Unknown strength | No: CDC says do not use it if the percentage "is not specified" | CDC [4] |
The simplest rule: turn the bottle around. If the label lists sodium hypochlorite between 5 and 9 percent, carries an EPA registration number and gives disinfecting directions, it is the product CDC's advice was written for.
The dilution, in one line
CDC's dilution for disinfecting with 5 to 9 percent bleach is 1/3 cup (5 tablespoons) per gallon, or 4 teaspoons per quart, of room-temperature water, left visibly wet for at least 1 minute and made fresh daily [4]. The full method, why other published dilutions differ, and why that page follows CDC are on the bleach disinfecting solution page. CDC also says to follow your bottle's own directions where it gives them [4].
Before you disinfect, clean. CDC's instruction is to clean visibly dirty surfaces with a soap or detergent cleaner first [4]; UF/IFAS adds a rinse between washing and sanitizing [5].
Never mix bleach with anything
CDC: "Never mix household bleach (or any disinfectants) with any other cleaners or disinfectants" [4], because doing so "can release vapors that may be very dangerous to breathe in" [4]. The Clorox SDS lists acids, bases and oxidizing agents as incompatible [1]. In practice the dangerous partners are:
| Partner | Where it hides | Page |
|---|---|---|
| Acids: vinegar, citric acid, lemon juice, many toilet bowl and lime removers | Toilet bowl cleaners, rust and scale removers, some tub and tile cleaners | Bleach and vinegar |
| Ammonia | Glass and multipurpose cleaners, urine in litter boxes and toilets | Bleach and ammonia |
| Rubbing alcohol | Hand sanitizer, alcohol wipes, glass cleaners | Bleach and rubbing alcohol |
| Hydrogen peroxide and other oxidizers | Oxygen bleach, some stain removers | Cleaners you should never mix |
UF/IFAS adds the instruction to dilute bleach with water only [5]. If you mix bleach with something by accident, leave the room and follow the I mixed cleaners page.
Clorox's hazard figures, line by line
| Item | The Clorox Company, Clorox Regular Bleach2 [1] |
|---|---|
| Date | Revision 3, December 9, 2020 |
| Sodium hypochlorite | 5 to 10% (exact figure withheld) |
| Classification | Skin corrosion/irritation Category 1B; serious eye damage Category 1 |
| Signal word | Danger |
| Hazard statement | "Causes severe skin burns and eye damage" |
| pH | 12.1 |
| Oral LD50, sodium hypochlorite | 8,200 mg/kg (rat) |
| Incompatible materials | Strong acids, acids, strong bases, bases, oxidizing agents |
| Conditions to avoid | Exposure to air or moisture over prolonged periods |
| Eye first aid | "Rinse immediately with plenty of water, also under the eyelids, for at least 15 minutes" |
| Skin first aid | Wash with soap and water; "Immediate medical attention is required" |
| If swallowed | "Do NOT induce vomiting. Rinse mouth immediately and drink plenty of water" |
The oral LD50 is high. The injury to plan for is a corrosive splash in the eye or on skin. CDC says to check whether you need gloves or eye protection and to make sure of good ventilation indoors [4]; the protecting yourself page covers both. For any swallowing or eye exposure, call Poison Control at 1-800-222-1222 [6].
Surfaces and fabrics
Bleach is an oxidizer and a strong alkali, so it removes color from fabric and can attack materials that do not tolerate either. The product label is the source to follow for which surfaces and fabrics it may be used on, and CDC's guidance is written for hard surfaces [4]. Laundry use, dyes and fabrics are on the bleach in the wash page, and the surface table sets out what the sources say surface by surface.
Storing bleach
The Clorox SDS: "Keep containers tightly closed in a dry, cool and well-ventilated place. Protect from moisture. Store locked up" [1]. At home:
- Keep bleach in its original bottle with the cap tight. Never transfer it to another container, and never a food or drink container.
- Store it apart from acids, ammonia and other cleaners, ideally on a different shelf, so a spill or leak cannot combine them.
- Keep it cool. Bleach loses strength over time, faster in heat; how long a bottle lasts and how to read its date code are on the does bleach expire page.
- A diluted bleach solution is a same-day product. CDC: make it fresh daily, because it "will not be as effective after being mixed with water for over 24 hours" [4].
- Lock it up or store it high if children live in or visit the house.
Choosing your bottle and using it
Buy regular, unscented bleach with the percentage, an EPA registration number and disinfecting directions on the label. Then use it one way only: diluted with water, on a cleaned surface, by CDC's method or the label's. The method is on the bleach disinfecting solution page.
References
- The Clorox Company, Safety Data Sheet: Clorox Regular Bleach2, revision 3, December 9, 2020. https://www.thecloroxcompany.com/wp-content/uploads/2020/12/US001153-Clorox-Regular-Bleach2_3.pdf
- Alliance Chemical, Safety Data Sheet: 5% Diluted Acetic Acid Food Grade, revised October 20, 2026. https://docs.alliancechemical.com/sds/5-acetic-acid-food-grade
- U.S. Environmental Protection Agency, Determining If a Cleaning Product Is a Pesticide Under FIFRA, last updated July 6, 2026. https://www.epa.gov/pesticide-registration/determining-if-cleaning-product-pesticide-under-fifra
- Centers for Disease Control and Prevention, Cleaning and Disinfecting with Bleach, last reviewed April 24, 2024. https://www.cdc.gov/hygiene/about/cleaning-and-disinfecting-with-bleach.html
- University of Florida IFAS Extension, Griffin and Cantrell, Homemade Household Cleaners (FCS3319), Release Date October 7, 2025. https://ask.ifas.ufl.edu/publication/FY1449
- Poison Control (National Capital Poison Center), Poison Statistics: National Data 2024. https://www.poison.org/poison-statistics
- Poison Control (National Capital Poison Center), Williams A. and Klein-Schwartz W., *Chlorine Gas*, undated, read October 2026. https://www.poison.org/articles/chlorine-gas
