Sewer Gas . . . By Any Other Name
It’s the holiday season and my thoughts are turning to the sweetness of summer. On more than one home inspection, after a rather uneventful hour at the hot and sunny exterior, the inspection party entered the house only to be assaulted by an overwhelming, sickening odor. Perhaps this has happened to some of you at a summer home that was locked up for the winter. Usually the cure is quick and simple. Hold your breath and open all the windows; then rush to flush every toilet, and run the water at every sink. These simple procedures fill the traps from which water has evaporated, as a result of months of disuse.
Most people think that sink traps are for catching wedding rings that fall from fingers, but the real reason for plumbing traps becomes obvious only when one has dried out. Traps are for stopping sewer gas odors, not rings. Every plumbing fixture must have a trap of some type. The most readily visible type is at the bottom of a sink in the shape of an uneven “U.” On toilets, the trap is actually built into the porcelain. Often, trap access nuts stick down below the plane of the ceiling surface in a room or garage.
Sometimes, sewer gases enter a dwelling, school or office without much obvious odor. This can occur at abandoned fixtures, air conditioning condensate drains or improperly placed rooftop, fresh air intakes, close to plumbing vent stacks. Even though unnoticed, breathing sewer gases can cause symptoms.
I was called by a couple who spent much of their day working in a 100 year-old home. Both husband and wife suffered from headaches since moving in. Because the home had a septic system, the basement waste line was close to the ceiling, and no basement fixtures were possible. The washing machine discharge hose extended high up to the plumbing drain, which consisted of nothing more than a “U” trap. When I entered the basement, my combustible gas detector began ticking at an increasing rate the closer I got to the washing machine trap. As the ticking got louder, the odor got stronger. Every time the homeowner used the washer, the drain trap filled with water as intended, but every time the washer pump turned off, the water in the vertical washer hose siphoned the water out of the plumbing trap. The homeowner put a cup of water into the trap after every wash-load, and their headaches went away.
I was called to an office where a pregnant worker felt nauseous every day after arriving at work. Co-workers felt that it was morning sickness but she insisted otherwise. Tucked in the basement was a plumbing pipe that had once served as a drain for an air conditioner. There was no water in the trap. At another building, management was complaining about sickening odors in corner offices. The building had a case of “adaptive reuse”; at one time it had been an elementary school, but the adults had no use for the upright row of a dozen urinals in the abandoned, basement boys’ room.
Sewer gases can even cause more serious health effects. In a lovely condo recently, a homeowner suffered from voice loss that might have been caused by sewer gases coming from a broken toilet seal. In concentrated form, as inside street manholes, sewer gases can displace all the oxygen and cause loss of consciousness.
If you’re a real estate agent with a vacant property in the summer, please be sure to enter the home before an inspection and check that the traps are filled! It’s a good idea to do so before a showing too, as this will avoid many embarrassing explanations and big disappointments. An unconscious buyer cannot make an offer!