How to Make a Bleach Sanitizing Solution Safely

Sanitizing or disinfecting?

The two words sound similar, but they call for different strengths:

• Sanitizing reduces germs to a safe level on surfaces that touch food, such as dishes, utensils, cutting boards and worktops. It uses a weak solution, measured in parts per million (ppm).
• Disinfecting kills more germs, for example on bathroom surfaces or after someone has been ill. It needs a much stronger solution.

Always clean off dirt with soap and water first. Bleach works poorly on dirty surfaces.

How strong should it be?

These are common guidelines. Local food-safety rules and your product’s label come first.

Use	Typical strength
Sanitizing food-contact surfaces	50–200 ppm
Disinfecting surfaces at home	about 1,000 ppm
Spills of blood or body fluids	up to 5,000 ppm

For food-contact surfaces, the US FDA Food Code calls for 50–100 ppm of chlorine, and US rules allow up to 200 ppm without rinsing. For disinfecting at home, the US CDC recommends 5 tablespoons (⅓ cup) of household bleach per gallon of room-temperature water, which works out to about 1,000 ppm.

Why your bleach’s strength matters

Household bleach is sold in different strengths, usually between 3% and 8.25% sodium hypochlorite. The label shows the percentage. A recipe written for 5.25% bleach makes a solution about 60% stronger if you use 8.25% bleach. That’s why it’s better to calculate from your own bottle than to follow a recipe blindly.

For example, to make 1 liter at 200 ppm:

• with 6% bleach, use about 3.3 mL (roughly ⅔ of a teaspoon);
• with 8.25% bleach, use about 2.4 mL.

Our bleach dilution calculator works this out for any strength and amount, and can also tell you how strong a recipe you already use really is.

Step by step

1. Check the sodium hypochlorite percentage on the label, and that the product is meant for disinfecting or sanitizing.
2. Work out how much bleach you need for the amount you’re making.
3. Pour cool or room-temperature water into a clean container, then add the bleach.
4. Stir, and label the container with its contents and the date.
5. Use it the same day, and throw away what’s left: bleach solutions lose strength over time.
6. If you work in a food business, check the strength with chlorine test strips.

Safety rules

• Never mix bleach with ammonia, vinegar, acids or other cleaners. It releases toxic gases.
• Use plain, unscented bleach.
• Work in a well-ventilated place, and wear gloves. Protect your eyes from splashes.
• Keep bleach and bleach solutions in labelled containers, out of reach of children.
• Don’t use this for drinking water: it needs far weaker doses and its own instructions.