kitchen sink plumbing - man working underneath sink

Kitchen Sink Plumbing: Everything You Need to Know, from Clogs to Leaks!

If you’re a homeowner, you’ve run across a kitchen sink that required plumbing help. That’s why we’ve created this article (and a troubleshooting guide) on kitchen sink plumbing to give you an overview of the most common problems and solutions.

The Basics of Kitchen Sink Plumbing

Most modern kitchen sinks are made of stainless steel or enabled steel. They usually have two basins draining into a trap that blocks sewer gas from entering the house. A trap arm joins the trap to the drainpipe at the wall.

Under a single sink is a one-piece fixed or swivel trap, consisting of a trap connected to a trap arm. If you also have a dishwasher, one of its drain hoses is attached to an air gap — a simple device that prevents back-siphoning. The second drain hose will attach to either the garbage disposal if you have one or the sink tailpiece if you don’t.

Common Kitchen Sink Plumbing Problems

The three problems (or projects) that most frequently plague kitchen sinks are clogged drains, leaky supply pipes, and the need to remove or replace a sink trap. The good news is that all of these can be handled with basic plumbing tools.

1. Clogged Drains

You can avoid clogs by placing strainer baskets in the drain openings and not pouring grease, coffee grounds, or other sticky objects down the drain. If a sink does back up, a plunger or auger will break up most clogs. There are also natural remedies you can try. (See Related Resources below).

We encourage you to never use harsh, toxic chemical drain cleaners. They don’t always work, are unsafe to skin and eyes, and can cause more damage to your kitchen sink plumbing. If you feel compelled to use one, be extra careful. Wear gloves and safety glasses, and only use them in an enamel or stainless-steel sink. They will damage the finish.

Serious blockages can be cleared by opening the trap below the sink or by probing the drainpipe behind the wall.

troubleshoot a garbage disposal - kitchen sink plumbing clogged
A common clog occurs by putting the wrong objects and foods down a kitchen drain. Often, these items are too sticky (like grease/oil) or too hard (like nuts) and cause blockages in the drain or garbage disposal.

2. Leaks

If you’re experiencing a leak under the sink, you might only need to tighten a loose slip nut on the drain assembly to stop it. If this doesn’t work, remove that part of the trap nearest the leak and install a new washer under the connecting slip nut.

Keep an assortment of washers on hand. Whenever you disassemble a trap, it’s wise to replace all the washers. A worn washer is the cause of many leaks and is so inexpensive and easy to replace.

How to find a water leak - water detection - woman looking at water leak causing water damage in kitchen sink plumbing
Use the kitchen sink plumbing troubleshooting guide and the Related Resources section (both are below) to learn about common leaks and solutions.

3. Removing a Trap

When you remove part of a trap, whether it’s the trap bend (the P- or U-shaped part) or the trap arm (the part that connects to the wall), you might decide that the piece is too corroded to reinstall.

Don’t worry. You can easily replace the damaged trap part with a metal or PVC plastic equivalent. Because it is light and easy to work with, plastic is especially suited for do-it-yourself plumbers. Heck, even professional plumbers use PVC.

what is a p-trap - PVC trap bend and trap arm
The trap bend (often called a P Trap) is the U-shaped part. The trap arm is the piece that connects the trap bend to the drainpipe in the wall. Notice the locknuts; they can easily be tightened and untightened by hand and an adjustable wrench.

Kitchen Sink Plumbing: Troubleshooting Guide

None of the solutions in this troubleshooting guide are considered complex. Nor should they take much time (unless you’re replacing an entire sink).

Final Thoughts

Thankfully, the clogs, leaks, and worn parts related to a kitchen sink’s plumbing are usually quick and easy to repair or replace. Of course, if you find more complex work, you can always call a trusted local plumber.

Call 1-Tom-Plumber

Don’t hesitate to contact us here or call us at 1-Tom-Plumber (1-866-758-6237) if you need help with your kitchen sink plumbing issues.

1-Tom-Plumber’s certified team of plumbers and drain technicians respond immediately to any emergency plumbing, drain cleaning, or water damage problem. We also handle the excavation of underground water lines and sewer main lines. Our immediate-response team is available every day and night of the year, even on holidays.

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