Informational Guide

How To Plumb Any Kitchen Sink

Learning how to plumb a kitchen sink yourself can save you a lot of time and money. We guide you through everything you need to know.

by Ian Haynes

DIY is becoming a lot more common, and more homeowners are jumping on board. This is largely because good quality guidance, premium materials, and useful tools are all much more accessible, making it easier to do the job without professional help. 

Plumbing is often considered something you can’t do yourself, but that isn’t the case. You can plumb a kitchen sink yourself, and it can save you a great deal of money and time. This guide will take you through everything you need to know so you can plumb your kitchen sink and install all the connections.  

Kitchen Sink 

This really is the centerpiece of your kitchen plumbing, and it’s hugely important in your home.

Your kitchen sink is made up of a number of different components with a metal strainer, a rubber gasket, a strainer nut, a tailpiece, a coupling, and then the trap. It’s important to understand how these fit together in order to plumb your kitchen sink correctly.  

How To Plumb A Kitchen Sink Drain

Garbage Disposal 

Your garbage disposal is used to help you get rid of food waste. The mechanism pulverizes the food and breaks it into smaller chunks to be washed through the system. This is really important because it stops your plumbing from becoming clogged with bits of food.  

Garbage disposals typically fit directly into your sink plumbing and have several components, plus a motorized mechanism to break up the food waste. This then connects directly into your plumbing. 

Dishwasher 

Dishwashers are now in almost every home and make it much easier to clean large numbers of dishes quickly. Typically, dishwashers are plumbed directly into your drain, but they may be routed through your garbage disposal so food waste can be dealt with.  

Refrigerator 

Refrigerators are absolutely vital to modern life. Refrigerators are plumbed using a copper tube with a nut, a T fitting, and a shut-off valve. Refrigerators are connected to your cold water line so they can produce ice.  

How To Plumb A Single Bowl Kitchen Sink

Considerations Before Installing or Replacing a Kitchen Sink  

Configuration

The layout and configuration of your kitchen sink will impact the type of sink you can install in your home. There are two main types of sink, and you’ll have to pick a model that will work in the space you have: 

  • Drop-in: drop-in sinks literally drop into a hole in the kitchen counter with a visible lip on the surface.  
  • Undermount sinks: these are fitted under the sink and look a bit more elegant but are more challenging to install.  

There isn't a great deal of difference in terms of plumbing, but drop-in sinks are the best option for DIYers.  

Kitchen Size 

The size of your kitchen will directly impact the size of the sink you select. Larger sinks offer some advantages, but they’re generally more expensive. You’ll need to measure the space before you buy to make sure your kitchen sink and the plumbing can all be accommodated.  

Traffic & Lifestyle 

Every sink has slightly different requirements, and this is typically influenced by the amount of use they get. In a busy household, your sink will see considerable wear and tear, and you need a tough material (like stainless steel) that will stand up to it. You also might want to consider a double basin sink, so you have more space for active use. Select a kitchen sink that fits your needs. 

Maintenance Requirements 

Finally, you need to consider how high maintenance you want your sink to be. A simple, no-frills sink can often be the way to go if you know you don’t have much time to dedicate to home repairs. A single hole sink can be good for DIYers, even if it’s a bit less elegant.  


Rough-In Height Of Kitchen Sink Drain  

The rough-in is the stage of the build where all your connections are installed, but nothing has been sealed or closed up. Effectively this is where you make sure everything is done correctly, and you may decide to bring in a professional to inspect this stage of the work.  

Typically, your kitchen sink drain should be about 20 inches above the floor, but this is influenced by a few key factors:  

  • P-Trap Location 
    You need to allow enough room so that your P-Trap is no more than 24 inches below the sink drain. You may need to raise your sink if this is an issue. 
  • Vent Height
    Vents allow air into your drains so they continue flowing as they should. Your vent should be 6 inches above the rim of your sink.  
  • Pipe Connections 
    Your pipe connections should be below your sink and no more than 18 inches from the floor. 
  • Type Of Sink 
    The type of sink you have will impact all your measurements. If it’s more compact, then you'll need to reduce your rough-in measurements and make it all a bit closer together. Larger sinks won’t have that same issue. 
How To Plumb A Kitchen Sink

How To Plumb Your Kitchen Sink  

It’s not every day that you'll want to change the plumbing under your kitchen sink, but if you're renovating the room or replacing the sink, it's important to understand how to do it. Here are our step by step guides to help you through the process:  

Plumbing A Kitchen Sink Drain 

To install a kitchen sink drain, you'll need a tape measure, pliers, a tube cutter, plumbers putty, and the drain kit itself. You’ll then need to follow the following steps:  

  • 1
    Measure up 
    You’re going to be dropping your sink into your counter, and you need to know the measurements. Measure the trap arm and check the height. If it's more than 16 inches, then you may not have the right angle, and you'll need to lower the drain. Remember, there should be a downward slope of about ¼ inch per foot. If you need to lower the drain, then bear in mind that this can be quite complicated. You may need to get a professional involved to help you. 
  • 2
    Add the strainer  
    Take the plumber's putty and push it into the underside of the strainer. Then push the strainer into the hole and twist, so it’s secure. Clean off any excess plumber's putty using a wet cloth.  
  • 3
    Install the underside of the strainer 
    Attach the underside of the strainer basket to the bottom of the sink. Do this by fitting a water-resistant washer and then sliding the strainer basket on top. Screw this in place and attach a nut. Use a wrench to secure this tightly.  
  • 4
    Attach the tailpiece 
    Measure your pipe and cut it to the appropriate length. Attach this to the strainer basket. 
  • 5
    Connect the tee fitting 
    This step is only important if you have two basins or a garbage disposal connected. Place a rubber compression gasket inside the drainpipe. This will create a watertight seal. Connect the T fitting into the tailpiece by sliding it so it’s 1-2 inches over the tailpiece and then sliding a connector over it. This connector can then be tightened using a wrench, so it’s secure. 
  • 6
    Connect your drain 
    The T fitting should connect into a trap. This is the curved part of the pipes, which will prevent any foul odors from the drains coming back up. This should fit directly into your drain.  
  • 7
    Test the sink  
    Check the flow of water and make sure everything is draining correctly. In some cases, it can be worth calling a professional to review the work.  

Plumbing A Kitchen Sink Drain With Dishwasher 

Dishwashers can eject water at considerable speed, and you must have the right plumbing in place to deal with it. One of the best ways to do this is to connect it up to your sink, and you can do this by: 

  • 1
    Remove the tailpiece  
    You’ll need to follow the instructions above to connect the drain, but you'll want to use a branch connection instead of a standard tailpiece. If you have the tailpiece connected already, you can remove it by loosening the nut and sliding the connector rink off. Make sure your water is turned off beforehand and that you have a bucket to catch any stray drips.  
  • 2
    Install the branch tail 
    Your branch tail connection can be fitted in a very similar way to a standard tailpiece. You’ll want to hold this in place and then slide a new connector ring over to secure it in place.  
  • 3
    Connect the Dishwasher 
    Connect your dishwasher by sliding your drain hose onto the extended fitting on the branch tail. Use a clamp to secure this in place, and then test all your drains to make sure they’re functioning properly.  

Plumbing A Kitchen Sink With A Garbage Disposal 

A garbage disposal works effectively with a sink because it allows you to break down food waste so it can pass through your plumbing without blocking it. Garbage disposals need to be wired in but make sure everything is disconnected while you’re doing the plumbing.  

How To Plumb A Double Kitchen Sink

Plumbing A Double Kitchen Sink 

Double sinks are convenient and are increasingly common. Plumbing a double sink isn't too different from plumbing a single basin sink. However, you will need to be more precise with measurement so everything lines up. There will only be one connection to the drain, so you need to connect the two sinks together in the plumbing.  

  • 1
    Install your strainers 
    Install and plumb your sinks using the steps above for a single basin sink, but remember to use a Tee fitting so you can install another connecting pipe.  
  • 2
    Connect your sinks 
    As shown in the image below, use a connecting pipe to join up the plumbing. This should be above your P-trap and drain as all the water needs to flow down a single route. Connect the pipe between the kitchen sinks and secure it in place using a connector ring, nuts, and bolts.  
How To Plumb Under A Kitchen Sink
  • 3
    Test the connection  
    Check the water flow and ensure that nothing is leaking. If everything is working, then it should be safe to use.  

How to plumb a double kitchen sink with garbage disposal 

With double sinks, you typically have a garbage disposal underneath one of the sinks. You’ll need to follow the steps above to install a garbage disposal in your sink and the steps to install a double sink. You’ll then need to connect the plumbing, so it all flows to a single drain. 

  • 1
    Connect the garbage disposal elbow 
    A pipe from the garbage disposal should go down into an elbow (which functions as a trap) which then loops back to connect your existing plumbing. The image below illustrates this. These pipes should then be held securely using clamps and connector rings.  
  • 2
    Test the system 
    Your plumbing will start to look a bit more complicated now but don’t worry. Just make sure you thoroughly test the system to ensure there are no leaks before you start using it.  

Plumbing A Kitchen Island Sink 

Plumbing an island kitchen sink isn't actually too different from plumbing a regular kitchen sink; there's just one key difference, the venting. A vent is typically installed 6 inches above the overflow level to ensure that air can flow in and the water pressure remains even. In an island sink, this isn’t an option.

Instead, you need to install an island vent that goes as high as possible within the cabinet before flowing through the drain. 

  • 1
    Connect your P trap 
    Use a pipe to connect your P trap to your venting. This will allow you to direct the water across to a tee connector, your vent, and your drain. Use connector rings to hold this in place, and use a wrench to tighten both ends. 
  • 2
    Attach your vent 
    Attach your venting pipe above the pipe to allow air to flow into your water supply. The other end of the venting pipe should go down into the floor and connect to your drains. Again, use connecting rings to secure in place and then a wrench to tighten.  

People also Ask (FAQs)

How much does it cost to plumb a kitchen sink? 

Kitchen sinks will cost between $100-200 to plumb yourself, factoring in the cost of materials and tools. To get a professional in will cost an extra $200-400 depending on the work needed. 

What pipes do I need for a kitchen sink plumbing? Can I use pex pipes? 

For a kitchen sink, you will need a hot and cold supply, so two separate pipes. PEX pipes are made with modern plastics, which are easier to install, making them a good option for DIYers. 

How do I remove kitchen sink plumbing? 

To remove the kitchen sink plumbing, turn off the water, remove the water supply lines, loosen the nuts, and remove the drain and P-trap. Then you can safely disconnect the garbage disposal and remove it from the system.  

Does a kitchen sink need a vent? 

Yes. Kitchen sinks need vents to equalize the pressure. Without them, the water won’t flow properly.  


Conclusion

DIY plumbing might seem intimidating, but it’s not as difficult as you might think. Choosing to do it yourself can save you a great deal of time and money, and hopefully, this guide has given you the confidence that you can successfully install a kitchen sink yourself. 

Ian Haynes is an expert writer who has successfully deployed over 500 plumbing pages and other related content. He has an excellent understanding of home plumbing issues and translates his experiences via Plumbing Lab so readers can have a better understanding of common household problems. Outside of his work, Ian likes exploring Brooklyn with his Labrador.

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