Many commercial drain cleaners contain corrosive or toxic products like sodium or potassium hydroxide, hydrochloric acid and petroleum distillates that kill sewage-eating bacteria and aquatic life and make water more expensive to treat.

You can buy enzymatic drain cleaners such as Earth Enzymes, available from The Green Store .

Or alternatively flush drains with a solution of boiling water, baking soda and vinegar, then use a plunger to agitate the mixture.

Another alternative is borax.