Low Temperatures Should Prompt Some Safety Checks

Sewer gas can become a serious threat when the mercury plunges to below zero and stays there for days at a time, according to a safety specialist at North Dakota State University.

"Not only does sewer gas smell bad, it’s poisonous and explosive. It’s not a situation you should ignore," says George Maher of the NDSU Extension Service. "Permanently solving the problem is usually best left to warmer times of the year, but you can do some thing to keep the gas out of your home until then."

The most common indication of sewer gas problem is it’s offensive odor. "Dried up basement floor drains and the drains of infrequently used sinks or showers are the usual points of entry into your home," Maher notes. "Don’t forget to check floor drains which may be covered with rugs or carpet."

Usually, solving this problem requires filling the drains with water regularly. Simply pouring a quart or two of water in the drains every week will seal out sewer gas, Maher says.

Another possible cause of the problem is poor venting of sewer gas from the waste plumbing of the house, he notes. Sinks, bathtubs, and other plumbing fixtures that do not drain normally are a sign of this problem If the problem is showing up in the dead of winter, ice may be plugging the sewer vent.

In very cold weather, naturally occurring moisture in the sewer gas condenses at the end of the sewer vent and ice forms. That ice can build up to such an extent that it restricts or actually plugs the end of the sewer vent, Maher explains.

The sewer vent is located on the roof, most often above the room or facility it serves. "Solving this problem requires extreme care because it may require you to work with ladders in snowy and icy conditions," Maher says. Removing ice accumulations from the sewer vent stack may solve the problem on a short term basis, but it will not prevent it from occurring again.

There are several permanent remedies for ice-plugged sewer vents and some work better than others. Insulating the vent pipe where it passes through the attic is one remedy for easily frozen sewer vents, Maher says. Wrapping a batt of fiberglass insulation around the vent pipe in the attic will usually do the job. For this solution, access to the attic space is required.

Another possible remedy is a selection from various styles of sewer vents that resist plugging. Look for these improved vents at hardware stores and home building centers.

###