When used as directed Bleach nor any other laundry product will harm your washer. There is a Rumor that bleach and other laundry products will damage your washer. If misused any product can do that. However use of a laundry product as directed will NOT cause harm to a washer. If that was so I would be the first to have it to happen.I have had NO such problems ever due to the use of bleach or any other laundry product. And in this plant THEY ARE MISUSED! Greatly. Strong Alkali products are used on a daily basis in home machines t. And extreme amounts of super strong bleach some 4x what you have at home are also used and I have NEVER had a machine fail due to the use of such products. I do not expect a home machine to last more than a year under the extreme conditions they are put thu. However to this date all have lasted at least 2 years and some much longer than that. Most see a avg of 300 loads per mo. and are still running when retired.