CHLORINE BLEACH SHELF LIFE - According to Clorox™, the amount of hypochlorite that is added to their bleach depends on the season in which it is manufactured, because temperature affects the decomposition rate of sodium hypochlorite. So, more hypochlorite is added to bleach made in the summer than in cooler months. Clorox aims to maintain a 6% hypochlorite concentration for at least six months after the manufacturing date, assuming the bleach is stored around 70°F. It takes about 4-8 weeks from the time chlorine bleach is made to when it gets to a store so that you can buy it to take home. This leaves you 3-5 months where the bleach is at the effectiveness level stated on its label.

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Chlorine Bleach Shelf Life

How Long Is Bleach Good?

by Anne Marie Helmenstine, Ph.D.

Bleach is one of those household chemicals that loses its activity over time. It doesn't matter whether or not the bleach container has been opened or not.

Temperature is the primary factor affecting how long bleach remains active.

According to Clorox™, the amount of hypochlorite that is added to their bleach depends on the season in which it is manufactured, because temperature affects the decomposition rate of sodium hypochlorite.

So, more hypochlorite is added to bleach made in the summer than in cooler months. Clorox aims to maintain a 6% hypochlorite concentration for at least six months after the manufacturing date, assuming the bleach is stored around 70°F.

It takes about 4-8 weeks from the time chlorine bleach is made to when it gets to a store so that you can buy it to take home. This leaves you 3-5 months where the bleach is at the effectiveness level stated on its label.

Does this mean bleach is useless after 3-5 months? No, because you probably don't need 6% hypochlorite for laundry and home disinfection.

The 6% hypochlorite level is an EPA disinfection standard. If you store your bleach where it can get warmer than 70°F, like 90°F, the bleach is still effective for around three months.

How Long Is Bleach Good?

So, when you buy a bottle of bleach, it has a shelf life. The bleach will be highly effective for around 6 months and fine for home use for around 9 months. Clorox recommends replacing any bottle of bleach that is over a year old.

Another way to tell if your bleach is expired is to note its odor. Don't open the bottle and take a whiff!

The human sense of smell is sensitive to bleach, so you should be able to smell it as soon as you pour it from its container. If you don't smell any bleach, it's likely most of the product has decomposed into salt and water. Replace it with a fresh bottle.

Maximizing the Bleach Shelf Life

If you want bleach to remain as effective as possible for as long as possible, avoid storing it in extremely hot or freezing conditions.

Generally, this means it's better to store a bottle of bleach in a cabinet inside the house, which has a relatively stable room temperature, 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.

Like other hazardous chemicals, make sure it's kept away from children and pets. It's also a good idea to store bleach away from other household cleaners because it can react with many of them to release toxic fumes.

Anne Marie Helmenstine, Ph.D.

Introduction

Ph.D. in biomedical sciences from the University of Tennessee at Knoxville - Oak Ridge National Laboratory.

Science educator with experience teaching chemistry, biology, astronomy, and physics at the high school, college, and graduate levels.

ThoughtCo and About Education chemistry expert since 2001.

Widely-published graphic artist, responsible for printable periodic tables and other illustrations used in science.

Experience

Anne Helmenstine, Ph.D. has covered chemistry for ThoughtCo and About Education since 2001, and other sciences since 2013. She taught chemistry, biology, astronomy, and physics at the high school, college, and graduate levels. She has worked as a research scientist and also abstracting and indexing diverse scientific literature for the Department of Energy.

In addition to her work as a science writer, Dr. Helmenstine currently serves as a scientific consultant, specializing in problems requiring an interdisciplinary approach. Previously, she worked as a research scientist and college professor. 

Education

Dr. Helmenstine holds a Ph.D. in biomedical sciences from the University of Tennessee at Knoxville and a B.A. in physics and mathematics with a minor in chemistry from Hastings College. In her doctoral work, Dr. Helmenstine developed ultra-sensitive chemical detection and medical diagnostic tests.

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https://www.thoughtco.com/chlorine-bleach-shelf-life-3976002