A double kitchen sink simplifies meal preparation and cleanup after meals. You can use one sink to prepare your meal and stack dirty dishes in the other sink. A double bowl sink also leaves your kitchen garbage disposal always accessible.
Yet, Sage Property Management recommends that just like with a single-bowl kitchen sink, double-bowl kitchen sinks also have problems. One of the problems with both sinks is that they get clogged. Kitchen sinks handle a lot of food waste, so it is no wonder that occasionally they get clogged.
When there are clogs in a double kitchen sink, they can manifest on either side or both sides of the sink. You could also encounter the strange phenomenon where one side of the sink backs up into the other. Why does one side of a double sink back up into the other side, and how do you repair it?
Why your double sink backs up to the other side
The cause of this problem could either be simple or complicated. There are five reasons why one side of your double sink backs up to the other.
The sink drain is clogged
If your double kitchen sink is backing up on one side, the first thing to do is check for obstructions in the drain. If one of the drainpipes is obstructed, water you pour into the drain will simply accumulate in the pipe until it overflows and backs up into one bowl of the double sink. If you think your drain is obstructed, try to flush it out with a plunger.
Clogged garbage disposal
A clogged or jammed garbage disposal unit can also affect the water flow from your double kitchen sink. To check if the problem is from the garbage disposal, unplug the unit and run water into both sides of the sink separately. If the sinks drain properly, you may have a clogged or damaged garbage disposal.
Blocked P-Trap
The P-trap can be found under the sink; look for a P-shaped pipe below your sink. Its purpose is to keep bad-smelling sewer gasses out of your home. Sometimes, this pipe can become clogged with grease and food particles. If this happens, water will not flow freely from your kitchen sink. To clean a blocked P-trap you must uncouple it and clear its contents.
A clog in the vent stack
A less common but highly plausible reason for one side of your double kitchen sink backing up into the other is that your vent stack is clogged. A vent stack is a group of vertical pipes that let air into the plumbing system so that water will flow freely. If the air stack is clogged, low air pressure zones will be formed inside drainpipes as water flows through them. This can lead to backups.
A blocked sewer line
The final and most extreme cause a double kitchen sink is backing up on one side is a blocked sewer line. When your sewer line is blocked and needs clearing, water from the sink drain will have nowhere to go but up through an opening that is close by. Though a blocked sewer line can cause backup in your kitchen sink, it is the least likely cause of the problem.
What to do when your double sink backs up on one side
To figure out the precise cause behind your sink malfunction, you will have to rule out every possible cause of the issue, starting with the simplest one. You do that by systematically following the given steps:
Use a plunger
If you think that the sink is clogged due to the fact that the sink drain is clogged, try to unclog the drain by using a plunger. If you cannot determine which sink hole is clogged, try plunging both. While plunging a sink hole, cover or plug the other sink hole.
Use vinegar and baking soda
Pour a cup of baking soda into each drain opening in all sinks, wait for a few minutes and then pour a cup of vinegar into each opening. Let the mixture sit within the drain for five minutes. Pour hot water down the drain to drain.
Use salt and boiling water
You may use boiling water and salt as alternatives in case you do not have vinegar at home. First, ensure that there is no standing water inside the sink. Fill all sink openings with half a cup of salt and follow it up with boiling water.
Clean the P-trap
If that does not succeed, you may need to remove the p-trap, in order to clean it. Removing a p-trap is easy; it requires a screwdriver and patience. Have at hand a bucket to catch any spillage in the trap.
Call your plumber
Lastly, if you have tried everything and the problem won’t go away, the only option is to get a plumber to unclog your kitchen pipes. The plumber will inform you whether the problem lies with your garbage disposal, vent stack or otherwise. A professional plumber will also inform you how you can avoid the problem in the future.