For general household disinfecting, mix 5 tablespoons (one-third cup) of regular bleach per gallon of room-temperature water. That ratio, recommended by the CDC, is strong enough to kill common bacteria and viruses on hard surfaces like countertops, sinks, and bathroom fixtures. Different cleaning jobs call for slightly different concentrations, though, so the right ratio depends on what you’re actually cleaning.
The Standard Ratio for Everyday Disinfecting
The go-to mixture for most household surfaces is 5 tablespoons of bleach per gallon of water. If you only need a small batch, use 4 teaspoons per quart. This works for countertops, door handles, light switches, toilet seats, and other hard, non-porous surfaces you’d normally wipe down.
Use regular, unscented household bleach with a sodium hypochlorite concentration between 5% and 9%, which covers the vast majority of bleach sold in the United States. Scented bleach, splash-less bleach, and color-safe bleach are not disinfectants. Check the label to confirm your bottle lists sodium hypochlorite as the active ingredient.
Stronger Ratios for Heavy-Duty Jobs
Some situations call for a more concentrated solution. The CDC provides two higher-strength ratios depending on the job:
- 1 cup of bleach to 5 gallons of water for sanitizing floors, sinks, toys, tools, plates, and flatware that may have been contaminated (for example, after flooding). Clean the surface with soap and water first, rinse, then apply the bleach solution and let it air dry.
- 1 cup of bleach to 1 gallon of water for heavily soiled or rough surfaces that need scrubbing, such as concrete, textured tile, or outdoor tools. Scrub with a stiff brush, rinse with clean water, and air dry.
These stronger mixtures are typically reserved for disaster cleanup, mold remediation, or situations where surfaces have been exposed to sewage or floodwater. For routine kitchen and bathroom cleaning, the standard 5-tablespoons-per-gallon ratio is sufficient.
How to Apply It Correctly
Bleach doesn’t disinfect on contact. The surface needs to stay visibly wet with the solution for several minutes to actually kill pathogens. Most bleach labels specify a contact time of around 5 to 10 minutes. If the solution dries before that window is up, it hasn’t done its full job.
Always clean the surface first. Bleach is a disinfectant, not a cleaner. Dirt, grease, and organic matter reduce its effectiveness, so wipe or wash the surface with soap and water before applying your bleach solution. Then apply the bleach mixture, let it sit, and allow it to air dry. Rinsing afterward is optional for non-food surfaces but a good idea for anything that will come into contact with food.
Mixing and Storage Tips
Mix your solution with room-temperature water. Hot water breaks down the active ingredient faster and can release more fumes. Use an open, well-ventilated area when preparing the mixture, and wear gloves to protect your skin.
A bleach-and-water solution loses potency relatively quickly once mixed. Make a fresh batch each time you clean rather than storing a pre-mixed solution for days. The bleach concentrate itself also degrades over time, especially if the bottle has been open for months or stored in heat or sunlight. If your bleach is more than a year old, it may no longer disinfect at the expected strength.
What Not to Mix With Bleach
Bleach reacts dangerously with several common household products. Mixing it with the wrong thing can produce toxic gases that cause serious injury within minutes.
- Ammonia: Produces chloramine gas, which causes coughing, shortness of breath, chest pain, and watery eyes. At higher concentrations it can cause pneumonia and fluid buildup in the lungs. Many glass cleaners and multi-surface sprays contain ammonia.
- Vinegar and other acids: Produces chlorine gas, which irritates the eyes, throat, and lungs almost immediately. Higher exposure levels can cause vomiting, severe breathing difficulty, and in extreme cases, death. Toilet bowl cleaners, rust removers, dishwasher rinses, and some glass cleaners contain acids.
- Hydrogen peroxide: Also reacts with bleach and should never be combined.
The simplest rule: never mix bleach with any other cleaning product. If you’ve just cleaned a surface with a different cleaner, rinse it thoroughly with plain water before applying your bleach solution.
Surfaces to Avoid
Bleach is safe for hard, non-porous materials like ceramic tile, glass, porcelain, and sealed countertops. It can damage or discolor several common household surfaces, though. Avoid using bleach solutions on natural stone (granite, marble, slate), stainless steel, wood, carpet, and colored fabrics. Unsealed grout can also absorb bleach and weaken over time. If you’re unsure about a surface, test a small hidden area first.
Quick Reference by Job
- Routine disinfecting (counters, bathrooms, handles): 5 tablespoons per gallon of water
- Small batch for quick wipe-downs: 4 teaspoons per quart of water
- Post-flood or contamination cleanup: 1 cup per 5 gallons of water
- Heavily soiled or rough surfaces: 1 cup per 1 gallon of water