MAINTENANCE : House That Burps Is Telling You to Check the Plumbing

All houses have their distinctive noises--the creak of particular floorboards, the whoosh of the furnace coming on, the whir of the sump pump.

Sometimes these noises are comforting, but if they seem to be murmurs of trouble, they can be downright annoying.

Some older homes, for example, have drains that burble and burp--as if they were gasping for air. Well, they probably are.

Plumbing fixtures need air for the same reason as old-fashioned soda cans you opened by making one hole to drink out of, and another to let air in as the liquid drained out. If you didn’t replace the air, the liquid wouldn’t flow freely.

Plumbing fixtures that drain water also need air to flow properly. They get it by means of vents, usually pipes that run from the fixture through the walls and out through the roof.

In some new construction, fixtures are placed close to a drain, which can also be used as a vent, or close to a wall, so they can be vented through the wall.

In older construction, the main drain for the toilet continues through the roof, to vent sewer gases. Sometimes other fixtures were connected to their own vents; but occasionally the toilet drain is the only vent for all the fixtures.

Fixtures that are inadequately vented make a bubbling sound because the system is trying to pull the air it needs through the drain traps.

Inadequate venting also makes drains run slow.

Vents can get clogged with leaves and other debris, and that can reduce or halt the air flow.

If that’s the case, a plumber might be able to clear them out and restore air to the system.

However, if the drains burble because there simply aren’t enough vents--and that’s common in old houses--the only way to add them is to tear out walls and ceilings and make new plumbing connections. And that’s a messy and probably expensive project.

It may be worthwhile just to accept the burblings as part of the house’s conversation.