Recent reports by the World Health Organization (WHO) said sewage can play a role 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. While the United States has not experienced a SARS outbreak like the one in China, investigators have uncovered information to prevent severe and common diseases from spreading in their homes through plumbing.

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 United States, 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," said Larry Rothman, master plumber with Roto-Rooter Services Co. "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."

U.S. health department officials have taken aggressive steps to prevent a SARS outbreak here.