The last couple of days, we’ve heard the kitchen sink gurgling when the clothes washer drains. The washer empties into a deep sink, and it’s draining better than ever. Both the kitchen sink and the deep sink drain into the same pipe. A year (year and a half?) ago, we discovered that the pipe had broken and was draining under the house. The was repaired with the proper pipe and the proper cement to join the pipes, and hangers were installed where there were none before. AFIAK, it was a good repair and I have not seen an excess of water by the crawl space. (A French drain now extends from the crawl space to where the yard drops off toward the creek.)
This gurgling of the kitchen sink may have always been happening and we just never noticed it. Or it may be new. Is it something to worry about?
I suspect the sink is gurgling due to improper/inadequate pipe venting. Plumbing drains need to be vented and this is usually accomplished with a vent pipe leading off a drain line with the vent pipe running up through the roof of a structure. One purpose of the vent is to allow air to enter the drain and let the water exit smoothly but it also allows sewer gas to escape from the drain.
Imagine this; If you fill a soda bottle with water and turn it upside down, the liquid will gurgle out as it exists. The same bottle turned 90 degrees allows the liquid to flow out more smoothly because air is allowed to enter the bottle as the liquid escapes thus equalizing the pressure.
You may need to add a vent pipe at the kitchen drain between the washer sink or there may be a partial or total blockage at your existing vent pipe. Another possible cause may be related to the prior repair as the height/slope of the repaired drain was altered and reduced the effectiveness of your existing vent. An experienced plumber should be able to figure it out. The gurgling isn’t a major issue unless the vent ceases to function which would greatly reduce the drain’s ability to remove water.
Yeah, gurgling is the classic sign of a stack venting problem. Other typical symptoms are slow draining of sinks and tubs and your toilet not filling up all the way. You can also have things like the toilet flushing when you drain the bathtub. Symptoms vary depending on the design of your plumbing, so you can easily have some symptoms but not others.
Since you don’t know if the gurgling is new or not, it’s possible that the sink was never vented right to start with. It’s also possible that this is new (or relatively new) and something is blocking the vent now. It’s fairly easy for the vent to get blocked by leaves and sometimes critters will find creative ways to block them up as well.
Sometimes just climbing onto the roof (not an easy task on some houses) and clearing the leaves around the vent will do the trick. Other times you have to open the vent up and clean it out with a plumbing auger. Be forewarned. Sometimes the thing that is blocking the vent is a dead bird or rodent that has lodged itself some distance down in the vent pipe.
Depending on how your house is laid out and how your plumbing is designed, you may have more than one vent in your home.
If you don’t fix it, you can end up with sewer gases backing up into your house.
Interesting. We had some roof work recently – new valleys, and replacing some attic vents.