In some older homes galvanized steel was used for sink drains. With years of chemical drain cleaners, grease,and soaps the waste arm will start to leak into your wall or ceiling. Unfortantly this may not be found until there is a clogged sink and the line is properly cleaned with a power snake as all the scale and debris that was preventing the pipe from leaking has know been cleaned and flushed out. Chemicals are hard on our drainage pipes and will create leaks. In Victoria BC our waste water enters our ocean, adding chemicals is harmful to both you and our wildlife, thats why CALLAWAY Plumbing and Drains Ltd. only uses the most up to date equipment and NO chemicals! So before you think about putting chemicals into your sink give us a call, we will clear out your drain the safe and professional way!