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Ask Dr. Laundry

Ask Dr. Laundry

Water Temperature and Bleach

By Dr. Laundry August 12, 2010

Recently my family was cleaning my grandma’s house. I was using hot water with bleach to wipe things down, thinking I was disinfecting the surfaces. My sister-in-law informed me that when you use hot water with bleach, you deactivate the bleach. I have never heard this before, is this true? She said to only use cold water with bleach when cleaning.

A. She’s probably referring to the CBS Early Show segment on Germ Warfare: The Laundry Room. While I didn’t see it live, I have reviewed the presentation and the only thing that I took issue with was their “expert” and his comment about bleach losing its efficacy in hot water.

The facts are:


  • Clorox® Regular-Bleach disinfects effectively in hot, warm or cold water whether for laundry or household cleaning/disinfecting.

  • For maximum cleaning, stain and soil removal, one should wash with hot water with detergent and Clorox® Regular-Bleach.

  • For household cleaning and disinfecting, Clorox® Regular-Bleach is the most cost-effective disinfectant and can be used in hot, warm or cold water.

  • Overall, the consumer has several choices to obtain sanitizing and disinfecting with Clorox® Regular-Bleach.

Hope this clears up any confusion on the subject. Let me know if you have any further questions.