When water is finishing running out of a drain, say in the basement utility tub, the drains in the upstairs bathrooms make this really loud "glug, glug, glug" noise. Any advise on what is wrong with the drains and how to fix the problem?
The upstairs sinks are not properly vented to the roof or the vent is obstructed. When water is poured down the drain the water fills the pipe and as it travels down, air must be added behind the water or a vacuum will form. This vacuum is sucking air in from the upstairs sinks causing the gurgling noise. It will probably require a plumber to figure out where the vent needs to be modified or repaired.