How to change a kitchen sink drain: in four easy steps

Every now and then a kitchen sink drain needs to be replaced. Most plumbing components will eventually need to be replaced, and if your kitchen sink isn’t draining as well as it should, it could be that it’s old and worn. And if you have to constantly fix it or use a plunger, now is the time to think about replacing the kitchen sink drain for smooth, easy water drainage every time.

However, before you replace a kitchen sink drain, make sure you’re not just trying to fix a clogged sink. “The main causes of clogged kitchen sinks are grease and food,” says Martha Stewart (opens in new tab). “That’s why it’s so important to scrape any crumbs off your plate and throw them in the trash before you give it a thorough rinse.”

Check your sink area regularly and look for signs of wear and tear. If yours is old and outdated, chances are the drain is too.

“Replacing the kitchen sink drain isn’t too time-consuming,” says Lucy Searle, Global Editor in Chief for Homes & Gardens. “It should take about an hour or two from start to finish, and it’s a task even the most inexperienced DIYer can handle. It’s time to replace it when the water isn’t draining properly and is difficult to fix, or when you’re replacing a kitchen sink as part of a kitchen makeover or update.

How to change a kitchen sink drain

Kitchen sink siphons can be purchased as kits with parts to fit your current configuration. So consider whether you need a trap for a single sink, double sink, or one with a garbage disposal.

There is also a choice of materials including PVC plastic (the most common option), chrome and copper. Since the drain of the kitchen sink is invisible in the kitchen sink cabinet below, most people opt for the plastic version.

You also need to check the size. Most kitchen sink drains are 1.5 inches in diameter, while bathroom sinks are 1.25 inches. Try to choose a kit with smooth tubing rather than corrugated tubing, as corrugated tubing can trap grease and food as it flows down the drain, causing constant clogs.

You will need:

  • Siphon set for the kitchen
  • Sink drain and strainer assembly
  • tape measure
  • marker
  • PVC hose cutter or hacksaw
  • Canal locks/pliers

1. Check the height of the tentacle

Give yourself a few hours of uninterrupted work time and get all your tools ready. Clear the area under the sink for work space and place a bucket under the plumbing. First look at the height of the trap arm under the current sink. You can find this by looking at the U-shaped bend (aka the P-trap) and the drain pipe that goes into the wall. In between is a trap arm, which is a horizontal piece of tubing. Note when we say “horizontal” that there is a slight slope from the side of the P-Siphon to the wall outlet/branch drain to allow for proper drainage – ideally the slope should be about 0.25 inches per foot.

Take your tape measure and measure from the floor or underside of the cabinet to the center of the latch arm. This is the length you will need for the new pipe.

The depth of the new sink must match the depth of your current sink to avoid having to move the trap arm. If the new sink is different in depth than your current one (especially if it’s deeper), make sure it can allow for the correct trap arm tilt. If this is not possible, you will have to move the drain in the wall, which makes the job considerably more complicated (see below).

2. Lower the drain outlet position

As we said above, if the new sink is deeper than your current one, you will very likely need to lower the drain. This isn’t a job for a novice handyman — or someone without the right tools: you’ll need to cut away more from the back of the kitchen cabinet as well as through the brick or masonry of the house’s exterior wall.

If you’re determined to do this yourself rather than hiring a professional, measure carefully to see if the lowered odor trap can still be removed for cleaning and unclogging in the future.

3. Disconnect and connect the drain pipes

Whether you bought a pre-cut piece of tubing to the required measurements or cut a longer piece with a small hacksaw or tubing cutter, precision is key. You are basically substituting like for like here so take photos as you go as it will help.

You will need to remove existing parts and install the siphon and drain pipe using sliding nuts and washers. Tighten by hand for now, making sure the continuous waste arm is tilted slightly downwards. Once satisfied, tighten with channel locks.

4. Check for leaks

Turn on the faucet and check all pipe connections for leaks. If necessary, tighten all connections, fill the sink with the plug, remove the plug and drain the sink – always with a bucket underneath, until satisfied.

Do I need plumbing putty to change a kitchen sink drain?

If you need to stop leaks, plumber’s putty (available on Amazon) (opens in new tab) is the perfect product. It is a sealing clamp used by professionals, DIYers and homeowners alike.

How do I remove a sink strainer?

To remove a sink strainer, use 16-inch slip-joint pliers or an open-end wrench to unscrew the existing strainer locknut. As the basket rotates, insert the tong handles into the top of the sieve and insert a screwdriver between the handles to hold it in place.

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