I have some gurgling in a sink. Its at the highest point of a lateral that has a sump pump discharging downstream. When the pump discharges, the sink gurgles. The lateral is 1.5" and connects further downstream with the main sewer exiting my basement.

The sink has a 1.5 vent that exits the roof. The downstream pump is below the sewer but discharges up to the lateral. There is an AAV on the lateral as well by the point where the pump discharge enters.

1. I would like to eliminate the gurgling. I assume that indicates a venting issue? How do I go about this?

2. If I install a new sink, should I gamble and add an AAV in the sink cabinet (which would be in addition to the 1.5 vent)? Would that stop the gurgling?

3. Help me understand what is occurring, why am I getting the gurgling in the first place?

Most codes do not permit a forced discharge into a sanitary system so that the traps are protected from siphonage. Remove the sump pump discharge from the system and discharge it independently to the exterior of the building.

when you re-do the kitchen, open the wall and cut a tee into the vent and drop that new vent line down into the basement and tie it in where the AAV is.

VEnts protect from siphonage, and a sanitary pump MUST discharge into the system, so a prohibition would be ridiculous. A "vent through the roof" is ALWAYS superior to an AAV so that should not help, unless the VTR is obstructed. Gurgling is either siphonage caused by the venturi effect of the pump discharge, or back pressure because the line is obstructed, but a functioning vent should eliminate either problem, unless the pump is not connected properly.

"Gurgling is either siphonage caused by the venturi effect of the pump discharge, or back pressure because the line is obstructed, but a functioning vent should eliminate either problem, unless the pump is not connected properly."

The vent out the roof appears unobstructed (water from hose on roof flows).

The pump discharges from a pit, has about 6' of vertical before connecting to the lateral with a tee... the AAV is about a 1' away upstream. There is no trap on the pump discharge (but it does have standing water in the pit and also has a check valve which hold water in the vertical portion of the discharge). The sink in question is up a level and flows downward to the lateral.

How should the pump be connected?

is the kitchen upstream or downstream from that sump pump tee connection?

The kitchen is upstream (farthest from sewer exit). The pump (and AAV) are in the middle.

The pump does not need a trap OR an AAV, although the AAV should be a nonissue. Does the gurgling occur while the pump is running, when it starts, or after it stops?

I get various degrees of gurgling when it first starts and then a moment later when it stops. A little one at the start and a longer fart at the end.



Edited 1 times.

I should also mention 1 time out of 10 it doesn't do it at all.

Any ideas? Or more specifically, what is the proper way to have this installed?

Checking back to see if Packy and HJ could shed some light on this one for me.... my family sure would appreciate it.