The pipes under your kitchen sink may appear intimidating, especially if you have two sinks, but replacing a sink drain pipe is easier than you think, even if you have no plumbing experience. Compression fittings connect the curved pipes, known as P-traps, to the sink drain and waste lines, and these can often be unscrewed without the use of a tool. If you're changing pipes to cure a leak, make sure the new pipes are aligned properly before installing them. The compression fittings will not seal if they are even slightly out of line, and the pipes will continue to leak.

How To Replace Drain Pipe Under sink

Here are the easy steps you can do to replace drain pipes under kitchen sink;

Remove the Old Pipes 2022

The first step in replacing a kitchen drain pipe is to remove the old piping. The major components of the plumbing that you'll repair normally come apart effortlessly, but a jammed pipe may necessitate the use of a few tools.

  1. Put a bucket beneath the curved parts of the P-traps and switch off the water valves to avoid being soaked if someone runs the faucet while you're working. Examine the pipe layouts, taking measurements with a tape measure if necessary, so that you may purchase the appropriate components and cut the pipes to the appropriate diameters.
  2. Remove the P-trap connections from the sink tailpieces (the pipes that extend down from the sink) and the drain. You can usually do this by holding each nut and twisting it counterclockwise with your hand. If it's difficult to spin, try adjustable pliers. To loosen the threads on metal traps, you may need to spray lubricant on the nuts.
  3. Remove the traps from the connectors, invert them to drain water into the bucket, and set them aside. Remove the tee if the traps were connected by a shared tee. In the same manner, disassemble any other pipes. If you only have one sink, you won't need a second trap, additional pipes, or a tee.
  4. If necessary, remove the drain tailpieces. They could be creating leaks if they're too short or rusted. To remove one, spin it clockwise using adjustable pliers to detach it from the drain.

And the first step is done!

Replace Sink Drain Pipe

You're ready to install your new pipes under the kitchen sink. The key to preventing leaks when installing new pipes is to ensure a precise fit and tight connections.

  1. Replace the tailpieces with new ones that are long enough to reach the same level as the drain pipe in the wall. Extend the tailpieces to a point about 2 feet above the bottom of the cabinet if the drain pipe is in the floor. With a hacksaw, cut the tailpiece as needed.
  2. To match the pipes you removed, use a hacksaw to cut new ones. Use a pipe with the same diameter as the one you're using, which should be 1 1/4 or 1 1/2 inches. Because PVC does not corrode, it is preferred over metal for kitchen drains.
  3. Assemble the pipes with compression fittings, hand-tightening the nuts until the P-traps are ready to be installed. Each trap should be slid up onto its proper tailpiece, tightened, and then swiveled to meet the drain pipe. Put that end of the trap together and tighten the nut.
  4. After you've finished assembling the sink, fill it with water. Check for leaks by opening the drain and letting the water go. Adjustable pliers should be used to tighten any leaky connections. 


Installing a garbage disposal unit in your kitchen sink to renovate it and make it more functional. Garbage disposals replace the typical P-trap beneath your kitchen sink by removing the curved piece of the pipe and connecting the disposal to your in-wall plumbing and dishwasher. Regardless of whether there was a previous disposal or you are installing one for the first time, most garbage disposal systems install in the same way.

How Do You Repipe A Sink With A Garbage Disposal?

  1. Turn off the water supply to the sink at the back of the cabinet's valves. Turn off the power to the outlet where the disposal device will be plugged in.
  2. Place a bucket beneath the P-trap in your kitchen sink cabinet and release the bolts holding the pipes in place with a basin wrench. To drain any remaining water, remove the pipes and place them in the bucket.
  3. Unscrew the sink strainer and pull it out of the way by loosening the nut keeping it in place.
  4. If the disposal unit's connector isn't already connected, connect it. Connect the chord wires to the unit, matching the colors black to black, white to white, and green to green, by unscrewing the bottom panel of the unit. Replace the unit's panel after twisting the wires together tightly.
  5. By twisting the mounting hardware away from the disposal, you may remove it. Remove the garbage disposal unit and set it aside.
  6. Apply a bead of plumber's putty around the drain aperture in the sink, then insert the disposal flange from above. From below the sink, slide the gasket over the flange's end. Below the gasket, slip the backup, mounting, and slide rings onto the end of the flange.
  7. Use a screwdriver to tighten the mounting screws that keep the mounting and slide rings in place. Tighten each ring a little at a time until they're snug.
  8. Turn the garbage disposal on its side and look for the dishwasher inlet. To break out the panel and provide an aperture for the dishwasher to connect to, place the end of the screwdriver against the knockout panel and strike the top with a hammer.
  9. Connect the disposal to the sink's mounting ring and align the disposal's top with it. The mounting ring should be turned until the disposal unit is securely in position.
  10. Make sure the dishwasher inlet is facing the dishwasher when you turn the disposal. Connect the dishwasher's discharge tube to the disposal and tighten the nut holding it in place with a tool.
  11. Connect the waste pipe to the back of the disposal unit's discharge and tighten it in place. To finish securing the disposal in place, tighten the screws holding the mounting ring in place. Turn on the water and electricity, and check for leaks in the garbage disposal.