Bleach Shelf Life: What you need to know.
Does Bleach Expire?
The simple answer is yes, bleach expires. According to the Scripps Research Institute, after a shelf life of six months, bleach starts to degrade. Even in its original bottle, bleach becomes 20 percent less effective as each year goes by. (source)
According to the Clorox™ website, a bottle of Clorox Regular Bleach “should be stored between 50°F and 70F°, and away from direct sunlight” and that pertains to bottles that are both sealed and opened. Clorox states that a bottle of bleach that has been correctly stored has a shelf life for about one year. They recommend replacing after one year since sodium hypochlorite begins to break down. (source)
Reading the Label
Bleach manufacturers do not list an expiration or “best by” date on the bottle; instead, they use a more specific manufacture date that lists the exact day the bleach solution was produced to ensure that only viable product is shipped to retailers.
To determine the expiration of a bottle of bleach, look at the first line of code:
- (A9) – refers to the plant that manufactured this particular bottle
- (20) – represents 2020
- (100) – is the 100th day of 2020 (April 10th)
The final two numbers, 07, are a manufacturing shift identification code. Given that bleach expires after about six months, use basic math to determine that this bottle will expire on October 10th, 2020. (source)
If you find an undated bleach solution in a spray bottle, don’t use it. Make a new batch and date it.
Maximize Shelf Life
To keep bleach effective for as long as possible, avoid storing it in extremely hot or freezing conditions. Temperature is a major factor in the shelf life of bleach, store a bottle of bleach in a cabinet inside the house, as opposed to a garage or outside storage shed.
Bleach is sold in an opaque container. Don’t switch it out for a clear container because exposure to light will degrade the chemical more quickly. (source)
Helmenstine, Anne Marie, Ph.D. “Chlorine Bleach Shelf Life.” ThoughtCo. https://www.thoughtco.com/chlorine-bleach-shelf-life-3976002 (accessed April 15, 2020).