Why is water backing up in my kitchen sink?

Author: Bernhard Bruen  |  Last update: Tuesday, September 23, 2025

Fats, Oils, & Grease One of the most common culprits of kitchen sink backups is the buildup of fats, oils, and grease. These materials may seem harmless in their liquid form, but once they cool, they solidify inside your pipes, creating a sticky mess that's hard to clear.

How do I fix the water backing up in my kitchen sink?

Pour one cup of fresh baking soda down the drain, followed by one cup of white vinegar. Place a rubber stopper or other sink hole cover over the drain opening. Wait 15 minutes to allow the vinegar and baking soda to unclog your drain, Then take out the drain cover and run hot tap water down the drain to clear the clog.

Why is my kitchen sink back filling with water?

Possible Cause: Clogged Sink. A clog in the sink itself is one of the more common reasons for water to back up. Using sink cleaners and snakes in the drain can often unclog the sink drain. You can also schedule a professional drain cleaning to see if you can unclog the sink drain.

Why is my sink backing up with no clog?

Slow drains may not always be due to clogs.

Plumbing vents, soap buildup, and garbage disposal malfunctions are among the most common culprits.

What does it mean when your kitchen sink backs up?

The Sink Drain is Clogged

If your double kitchen sink backs up to the other side, the first step is to check for any clogs in the drain. This can be done by looking for any debris accumulated in the pipe. If you find any blockages, you can use a plunger to dislodge them.

How to UNCLOG a kitchen DOUBLE SINK with Garbage Disposal EASY and CHEAP. NO HARSH CHEMICALS NEEDED!

How to unclog a kitchen sink with standing water?

First, remove all stagnant water from the sink. Replace it with hot water until it is halfway full, and it generates a seal around your drain. Place the sink plunger over the drain and start pumping up and down swiftly. Remove the plunger, observe if the water flows, and repeat the procedure until water flows freely.

Why would water come back up the sink?

So, when you notice water backing up through the plug hole instead of smoothly draining away, it's a cause for concern. This unexpected issue is a clear sign of a problem in your drainage system, most likely a stubborn blockage.

What is the best thing to unclog a kitchen sink?

Method #1: Use a Plunger

A plunger is one of the simplest and most effective tools for clogged sink drain in your kitchen. Here's how to use it: If your sink has an overflow hole or you're dealing with a double sink, cover the other drain or hole with a wet cloth. This will help build pressure when plunging.

Can a sink drain unclog itself?

Just watching that dirty water sitting there is enough to throw up your hands and avoid the kitchen, hoping the problem will fix itself (it won't). There are a few simple, lost-cost methods for unclogging a kitchen sink, including using a plunger, snake/auger, or baking soda/vinegar mixture with hot water.

Why is my sink clogged but pipes are clear?

Airlock or Plumbing Vent Issues: Sometimes, it's not food residue, oil, or hair that gets trapped in your pipes, but air, making it seem like your pipes are seemingly clear.

Why won't my kitchen sink hold water?

If your sink won't hold water, chances are the stopper isn't seating securely over the drain hole, or there could be leakage due to a bad stopper gasket.

Is drano bad for pipes?

The Short Answer Is: Drano and similar chemical drain cleaners can be harmful to home drain pipes as they contain corrosive chemicals that may deteriorate pipes over time, especially if used frequently.

How do I stop water from backing up?

If you do not have a backwater valve, plugs with backflow devices can be installed in floor drains. These plugs have a ball or float that will stop water or sewage from backing up into a home while permitting water to flow into the drain. These plugs can be left in place year-round.

How to unblock a kitchen sink without a plunger?

Bicarbonate of soda (or baking powder) and white vinegar

All you need to do is pop a couple of teaspoons of bicarbonate of soda down the plughole and chase it with a cup of white vinegar. Leave it for about five minutes and then try flushing the blockage with the hot kettle water.

Why is my sink draining slow but not clogged?

Your plumbing system has a vent that allows air to flow through the pipes. If the vent is blocked, it can cause water to drain slowly. You can check the vent outside your house to make sure it's not blocked by leaves or other debris.

How do you tell if a P-trap is clogged?

A blocked p-trap will cause water backflow to occur. The first sign that your p-trap is clogged is when the water in your sink takes longer than average to flow down the sink.

What does a P-trap look like?

P-traps, named after their shape, contain a u-shaped bend that filters wastewater as it enters a plumbing system. The trap is connected to a sink, bathtub, and shower with a J-bend on one end and exits into your drainage system. The J-bend is the section of the p-trap that resembles the letter J.

What is the best thing to unblock a sink with?

Baking Soda and Vinegar

Make sure you clear any standing water in the sink first, then pour a cup of baking soda down the drain. Follow this with a cup of vinegar, and immediately put the rubber stopper in the drain. The mixture will fizz, and push the clog down. Follow with hot water from the tap to finish flushing.

How to clean a p-trap without removing it?

Pour some baking soda down your drain and then pour boiling water down after. Sometimes this will clear the clog. Use a plunger on your sink drain to try to force the clog out of the trap.

Why is my kitchen sink backing up on both sides?

Primary Causes of Double Kitchen Sink Backflow

Food debris: When food or grease builds up in your drain, it can completely block the pipes or stick to the walls, restricting water flow. Soap scum: It's common for soap scum and hard water minerals to accumulate in your pipes over time, causing a backup.

How to stop a kitchen sink from backing up?

Use a drain strainer in your kitchen sink to help keep the food out.
  1. Don't pour grease or oil down your sink drain. ...
  2. Pour a kettle of hot water down your kitchen sink drain once a week to melt away any fat or grease that may have collected inside your pipes.

What does it mean when water backs up?

Water Backing Up: Water coming back up from the shower, tub, or sink drains, especially when you flush the toilet, is a clear indicator of a clog in your sewer line. Wet Floor Drains: If the floor drain in your laundry room or basement is wet or overflowing, this could be an early sign of a sewer backup.

Why is water backing up in my kitchen sink with a garbage disposal?

Blocked Disposal Unit: Food scraps or foreign objects may become lodged within the disposal unit, hindering the blades' ability to grind waste effectively. This blockage can cause water to back up into the sink when the disposal is turned on.

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