How much bleach per gallon of water to disinfect?

CDC's figure is 5 tablespoons (1/3 cup) of bleach per gallon of room-temperature water, or 4 teaspoons per quart, made with regular unscented household bleach that contains 5 to 9 percent sodium hypochlorite [1]. Leave it on the surface for at least 1 minute, keeping the surface visibly wet, and mix a fresh batch each day [1]. That is the only bleach dilution given here for disinfecting. If your bottle has its own disinfecting directions, follow those instead. Below: how to check your bleach, the steps, how to stay safe while you do it, and why other published figures differ.

CDC's instruction, word for word

From CDC, Cleaning and Disinfecting with Bleach, last reviewed April 24, 2024 [1]:

"If your bottle does not have directions, you can make a bleach solution by mixing: 5 tablespoons (1/3 cup) of bleach per gallon of room temperature water or 4 teaspoons of bleach per quart of room temperature water"

And on contact time, CDC says to "leave the diluted bleach solution on the surface for at least 1 minute before removing or wiping" [1].

Two conditions sit inside that instruction. It applies only to bleach in the 5 to 9 percent range, and only "if your bottle does not have directions." When the label on your bleach gives a disinfecting dilution, that label is the instruction for that product.

First, check the bottle

CDC says most household bleach contains 5 to 9 percent sodium hypochlorite and tells you to use regular, unscented household bleach in that range [1]. Before you mix anything, read the label for three things:

The different kinds of bleach on the shelf, and what each label allows, are covered on household bleach.

Making and using the solution

1. Clean the surface first. CDC says to clean visibly dirty surfaces with soap or detergent before disinfecting [1]. Dirt gets in the way of the bleach.
2. Open a window or door. CDC asks for good ventilation when using bleach indoors [1].
3. Decide on gloves and eye protection. CDC tells you to check whether you need them [1], and your bleach label's precautions say what that product calls for. More on choosing protection is on do I need gloves, eye protection or open windows?.
4. Measure into room-temperature water. 5 tablespoons (1/3 cup) per gallon, or 4 teaspoons per quart [1]. A quart is 32 fluid ounces, so the quart figure suits a standard 32-ounce trigger spray bottle. Use a measuring spoon or cup kept for cleaning only.
5. Use only water and bleach. CDC says never to mix household bleach with other cleaners or disinfectants, because the vapors can be very dangerous to breathe [1]. No vinegar, no ammonia, no dish soap in the bottle.
6. Apply and wait. Wet the surface and leave it for at least 1 minute, keeping it visibly wet the whole time [1]. If it starts to dry, apply more. Why the wait matters is on contact time.
7. Wash your hands when you finish [1].
8. Pour out what is left at the end of the day. CDC: "Bleach solutions will not be as effective after being mixed with water for over 24 hours." [1] Make a fresh batch the next time you need it. How long undiluted bleach keeps is on does bleach go bad?.

Labeling the bottle

Label the spray bottle with what is in it and the date you mixed it, and keep it out of reach of children. Never put a bleach solution in a bottle that once held food or drink, where someone could mistake it for something to drink. Labeling and container choice are covered on what should I keep a homemade cleaner in?.

What not to do with it

• Do not mix it with anything except water. Bleach with vinegar or another acid releases chlorine gas, and bleach with ammonia releases chloramines. Each pair has its own page, starting with bleach and vinegar, and the full list is on cleaners you should never mix.
• Do not use it right after an acidic cleaner on the same surface without rinsing between them. See is it safe to use one cleaner and then another?.
• Do not make it stronger. CDC's figure already has a stated contact time. More bleach means more fumes and no shorter wait.
• Do not keep yesterday's batch. See step 8.

If someone splashes the solution in their eyes or swallows some, call Poison Control at 1-800-222-1222. First steps are on someone got cleaner in their eyes or swallowed some.

Why other published dilutions differ

If you have searched this question, you have seen other numbers. University of Florida IFAS Extension's Homemade Household Cleaners (FCS3319, Release Date October 7, 2025) prints separate bleach-and-water ratios for a sanitizing solution, a disinfecting solution and a mildew cleaner, plus a fourth figure as an example in its safety notes, and none of them is CDC's figure [2]. USDA's cutting board advice gives yet another ratio for sanitizing boards [3]. Lifestyle sites repeat whichever one they found first.

They differ for reasons that make sense once you see them. A sanitizing solution for food-contact surfaces is a different job from disinfecting a bathroom. Each figure was written for its own purpose and its own contact time, and a dilution means little without the strength of the bleach that goes into it and how long it stays wet.

This page follows CDC for disinfecting, for two reasons. CDC is the federal public health agency, and its figure comes with a stated bleach strength (5 to 9 percent) and a stated contact time (at least 1 minute) [1]. The other figures are not reprinted here as recipes. For food-contact sanitizing, where CDC's bleach page gives no figure, the food-contact directions on your bleach label are the ones to follow, or on a registered sanitizer; see sanitizing kitchen surfaces and cutting boards.

The other valid direction: your bottle's label

Bleach sold as a disinfectant is an EPA-registered product, and its label carries an EPA registration number and its own disinfecting directions. CDC's own first instruction is to follow the manufacturer's directions when they exist [1]. If your bottle's label gives a different dilution or a longer contact time than CDC's, the label is what that product was tested and registered to do. EPA keeps lists of registered disinfectants searchable by registration number, and choosing and reading a registered disinfectant explains how to look yours up [4].

Getting the one-minute wait right

The step people most often cut short is the wait. What "contact time" means, why wiping too soon fails, and what to do when a surface dries early are on contact time.

References

1. CDC, Cleaning and Disinfecting with Bleach, last reviewed April 24, 2024. https://www.cdc.gov/hygiene/about/cleaning-and-disinfecting-with-bleach.html
2. University of Florida IFAS Extension, Homemade Household Cleaners (FCS3319), Amanda Griffin and Randall A. Cantrell, Release Date October 7, 2025. https://ask.ifas.ufl.edu/publication/FY1449
3. USDA Food Safety and Inspection Service, Cutting Boards, undated. https://www.fsis.usda.gov/es/node/3305
4. U.S. EPA, Selected EPA-Registered Disinfectants, last updated August 24, 2026. https://www.epa.gov/pesticide-registration/selected-epa-registered-disinfectants