Gurgling Kitchen sink

[The Undertaker]

My kitchen sink is gurgling. It started off as a slight gurgling sound but now its a longer gurgling sound. No water is coming up though. The noise happens after the following:

-after running the water in the kitchen sink (heavy sounding)
-the washing machine drains its water (heavy sounding)
-toilet flushing (very minimal gurgle)

No other fixture in the house makes this noise. I have no water backing up anywhere.

A local plumber came to investigate and could not isolate the problem because he could not locate how the kitchen sink drains into the main drain line. (The kitchen is on the east part of the house and all other drain fixtures including washer and main drain line is on the west part of the house) The kitchen sink drains to the sewer line but the connection is not present. It’s an old 1930’s house. In addition the vent pipe is on the west side of the house. There is no vent pipe on the east side (kitchen side). However, this has always been the case.

Plumber opened the cap to the main drain line and said water is flowing freely therefore no obstruction and with the cap off tested to see if letting air into main drain line would help ease gurgling sound, but it did not.

Plumber snaked kitchen drain about 40 feet as a precautionary but the sound still exists. He suggested its probably a clogged vent pipe and it would require someone to climb up there and inspect it. He can’t as they are not insured for roofs.

Would everyone agree it’s the vent pipe that sticks through the roof or something else?

 

[Addison]

Just curious, septic or city sewer?

 

[Sponsor]

 

[Jadnashua]

Your kitchen sink on an old house may not be vented per today's codes. Gurgling at a drain fixture when something else is draining is an indication that it is being siphoned. That can't happen if that line is properly vented. Air must get back through the line to prevent siphoning the p-trap at your kitchen sink. If your drain lines elsewhere are partially restricted (more common if things are partly galvanized versus cast iron), over time, and you're draining a high volume (like a washing machine or a toilet), there may no longer be enough space in the pipe to allow air to get back to the kitchen sink to prevent it siphoning (the gurgling you hear).

If allowed where you live, you might resolve the issue if you install an AAV at the kitchen sink. This opens up to let air into the pipe after the p-trap if there's a suction on the line, preventing it from siphoning the trap, then closes to block sewer gasses. They last a long time, but eventually need to be replaced, so it needs to be accessible.

If things worked for a long time, something has changed, and is pointing towards maybe needing to plan for some future major remodeling to bring things up to code. You're grandfathered, but that does not mean things will continue to work. The codes change over time by lessons learned about what works and how to resolve the problems.