haunted bathroom sink?

[Greg Stanford]

This is way off topic but I'm hoping someone will have an idea of what's going on. We moved into this house, which is about 50 yrs old, back in December & the master bath sink has been somewhat slow to drain. It worked & there were other, more pressing, issues that needed tending to so I haven't worried with it. Last night, I turned both hot & cold on full & let them run, the sink filled up about three quarters of the way & then drained all the way down -- quickly! After the water drained out, the sink then filled up about three quarters of the way & then drained all the way down --again quickly. It does the same thing when I used the plunger, I get some water in the sink, plunge it once & it drains quickly all the way, but then it starts to fill back up. Now (& I think this is the clue), there is air bubbling up from the drain, particularly right before the water starts to run out. I'm sure that means something, I just don't know what-- poltergeist?

g

[Joe Pelonio]

Time to call in Ghost Hunters! :D

A blockage of the vent can cause that sort of odd behavior. Maybe a creature went down the top of the vent on the roof, got stuck and died. Sometimes that can be cleared by a high pressure nozzle on a hose shoved down it from the roof.

I've also seen it happen with a main sewer line blockage (like from roots) but normally that would happen on the closest sink/tub to the line. For example you drain the tub upstairs in the master bath and the sink in the powder room downstairs fills up.

[Mike Cutler]

You probably have a vent problem. Your sink is acting to equalize the pressure in the DWV piping associated with the sink. The pressure, or vacuum is siphoning back and forth.
It is "clean water" coming back into the basin isn't it?

Regardless, it's time to contact your friendly neighborhood plumber.

[Greg Stanford]

"It is "clean water" coming back into the basin isn't it?"

The water is not coming back up from the drain, I have the water running into the sink the whole time. The water will rise & then drain quickly & then rise again. I'll try running a hose down the vent from the roof & see what that will do. Thanks.

g

[Tom Godley]

It does sound like a vent issue

You could have a small blockage in the line causing a vortex at that point - like trying to pour soda from a large bottle. But that is a vent issue in a different way

Check the vent from the roof.

With the house being 50 years old it may have been built with poor venting in the first place. Many house were built with only one vent at the main bathroom.

I redid an expanded cape that was built with only one vent -- The kitchen was not vented same with master bath.

[Jim Becker]

Think vent as already suggested...particularly because of the water return to the bowl after draining...probably caused by a bubble as the pipe tries to vent from below, rather than above.

[Lee Schierer]

It sounds like my house. The non-plumber who built it only put in one vent for the whole house. The bathroom sink was the only fixture with a vent line. Used to get gurgling in every other sink in the house every time the toilet flushed until I fixed the vent problem.