Using bleach seems like a great idea for keeping pipes unclogged and smelling fresh — and a drain cleaner is literally for pipes, right?
Unfortunately bleach can react with substances in your pipes and cause more clogs than it prevents. Even a drain cleaner is rough on pipes — and both are environmentally awful. (Plus, if you have a septic tank, as little as one teaspoon of a drain cleaner is supposed to be able to destroy a septic field.)
Instead, it's best to use a pipe snake (also known as an auger) to keep pipes running smoothly. It's easy to use; free once you pay a small amount for the purchase of the auger; and much safer for you and the earth.
Source: Excerpts from Kelley Walters for Realtor Online