The image shows a modern double sink in a light-colored countertop with a black faucet. A bowl of fruit is placed on the counter. Large windows in the background reveal a mountain and water view.

 

Double sink plumbing is different, but it is worth it. You have to turn off the water supply, install the sink strainers, measure the drain outlet height, connect the drain tailpieces and sanitary tee, install the Y-connector, attach the P-trap, connect the main drain pipe, and seal the joints. 

To help you understand and deal with dual sinks, we have prepared this guide with detailed steps and the answers to other common questions about double sink plumbing. Start reading to learn more and discover a complete diagram with instructions!

Do Double Sinks Need Two Drains?

No, double sinks do not necessarily need two separate drains. Using a double-sink waste kit or a Y-connector, which combines the drainage from both sinks into one pipe before connecting to the main drain, both sinks can share a single drain.

If you plan to remodel your kitchen, a double sink is a great addition to make your daily chores more practical! 

How To Plumb A Double Sink?

For proper dual sink plumbing, you do not need to know the secrets of plumbing. Still, you must turn off the water supply, install the sink strainers, measure the drain outlet height, connect the drain tailpieces and sanitary tee, install the y-connector, attach the p-trap, connect the main drain pipe, seal the joints, and test for leaks. 

  1. Turn off the water supply to the sink. 
  2. Apply plumber's putty around the edges of the sink drain holes and install the sink strainers into the drain holes. Use a wrench to tighten the lock nut underneath the sink.
  3. Attach tailpieces to the bottom of each sink strainer. The tailpieces direct water down from the sink into the plumbing.
  4. Connect the tailpieces to the Y-connector or double-sink waste kit, which will merge the two drains into one pipe. 
  5. Connect the tailpieces to the waste kit using PVC pipe and fittings. If using PVC cement, apply a light coat to both the pipe and fitting, then connect and hold in place for a few seconds.
  6. Attach the P-trap to the bottom of the Y-connector.
  7. If the drain pipes under the sink align with the existing plumbing, connect the P-trap to the main drain pipe. 
  8. Use plumber's tape on threaded connections to create a watertight seal. All connections must be secure, but remember to avoid overtightening.
  9. Turn the water supply back on and run both sinks. Check all connections under the sink for any plumbing leaks. If they occur, tighten connections or reapply plumber's tape as needed.

For a better understanding, you can check out the double sink plumbing diagram below!

 

This diagram shows the plumbing of a double kitchen sink, including key parts like the disposer, Y-connector, P-trap, and drain. It also highlights connections to the dishwasher, water supply, and shutoff valve.

 

How Much Does It Cost To Install A Double Sink?

The cost to install a double sink typically ranges from $300 to $1,200. Labor alone usually costs from $150 to $400, the price of the sink stays between $100 and $600, depending on style and material, and the plumbing materials range from $50 to $200

With or without experience in installing or repairing fixtures, calling a Wisercosts' plumber is the best way to make sure your double sink plumbing will work appropriately for a long time. Do not hesitate to contact them!