Recent reports by the World Health Organization (WHO) have shed new light on the role sewage plays in spreading the deadly disease known as severe acute respiratory syndrome, or SARS. The issue emerged following a SARS outbreak at the Amoy Garden apartment complex in Hong Kong.

According to WHO, ineffective U-trap seals in the drainpipes of Amoy Garden apartments triggered the SARS outbreak. These traps, often called P- traps in the U.S., are designed to hold water at all times. The water acts as a barrier and prevents insects, foul smells, and in this case, viruses and bacteria from backing up through the drains.

"Every U.S. plumbing fixture--a toilet, sink, bathtub or floor drain--uses a P-trap in its drainpipe. When the P-trap failed in the Amoy Garden apartment complex in Hong Kong, the plumbing system, in effect, acted as a transportation system for the virus to spread quickly through the building," said Larry Rothman, master plumber with Roto-Rooter Services Co.

Roto-Rooter reports that the plumbing systems in American homes and apartment buildings use P-traps similar to those in Hong Kong. While U.S. health department officials have taken aggressive steps to prevent a SARS outbreak here, Roto-Rooter also advises that property owners keep drains and P-traps clean in order to stop the spread of disease. Visit the WHO Web site at for more information on the spread of SARS.