Kitchen Plumbing

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A kitchen's plumbing consists of water and gas supply lines, both of which are essential to your kitchen's functioning. If you get them wrong, the plumbing in your kitchen sink could stop working, or you could end up with sewer gases and damaged slip nuts on your hands.

You don't wanna land yourself in hot water!

The plumbing in kitchen sink units and other kitchen appliances can be visible or hidden entirely. As such, you usually need the phone number of a plumber (kitchen sink specialist) who can give you professional help. Still, from the drain to the water heater, there are a lot of elements to kitchen plumbing in your home!

Here Kitchen Infintiy will take a look at your kitchen plumbing in more detail!

The Kitchen Plumbing System

Following are some components of a kitchen's plumbing system:

  • Dishwasher supply: Water pipes connected to the dishwasher.
  • Water supply : Placed below the sink for hot and cold water. Also attached to other fixtures that need water like the dishwasher or any additional sinks in the islands etc.
  • Drain: The system that takes the waste water out.
  • Flexible supply tube: These tubes connect the valves to the kitchen faucet.
  • Shutoff valve: This is used to control the flow of the water and manage the water pressure and completely shut off the water if needed.
  • Gas valves: They control the natural gas and are placed on the walls or below the floors

But why do you need to know about this? isn't this a plumber's job?

Kitchen Plumbing Process

Plumbing is based on two systems: one to get the water in and the other to get it out.

Installing a drainpipe is not a very complex process. But is important to keep things in mind like drawing a proper plumbing plan, hiring a plumber, insulating the pipes etc.

Here is a detailed overview of a kitchen plumbing process!

kitchen plumbing process
Image credit: Kitchen Infinity Photo

Kitchen plumbing plan

Planning everything wisely before you start working on it is important.

In this case, design a plumbing plan first, address all your kitchen plumbing problems and some new additions you may need for the kitchen. Get your plumbing plan approved by a plumbing inspector and start the plumbing process.

Hire a plumbing contractor

Plumbing can be a tacky process if not done right. You should hire a plumbing contractor to install the plumbing system to avoid any mistakes. If you've already had the plumbing system installed, ask your contractor to check the system for faults or fix leaky faucets yourself.

Installing the drainage system

The drainage system take the waste water out of the kitchen and are usually angled downwards towards the sewage systems.

This also includes installing traps and cleaning vents. Adding air supply through the vents is also important to make the waste go through properly.


Traps are important and are placed under every sink. It the ‘S' shaped section you see on pipe and the water passes through a trap into the drainage and some water is kept to prevent sewer gas from entering your home, hence the name ‘trap'!

Every fixture has a trap except toilets.

traps under sink
Image credit: Kitchen Infinity Photo

Air Admittance Valves

As mentioned above, air vents are important to keep the waste drainage smooth. These are run by gravity and open up to let some air in. They are placed between the p-trap fixtures and the drain line. Choose an air vent system that is suitable to your conditions.

Insulating Pipes

Insulating the pipes is really important for damage control and save you a lot of trouble with plumbing problems by protecting the pipes. Insulating the pipes also works are water heaters or coolers, however you need it to.

This is done by wrapping it in pipe sleeves, putting them behind wall insulation or foam wraps.

Supply System

As the name suggests, supply system bring in the water to your kitchen. It is the one of the two subsystems of kitchen plumbing and has been modified over the years to supply hot water and cold water separately.

The previous ones were only made to bring in cold water but the hot water demand especially cold climate areas has lead to the change in the design.

The supply system provides water to the sink which is why it's important to understand how to plumb kitchen sink.

Plumbing Kitchen Sink

Sinks are connected to the home's main water supply and designed to be connected with a faucet, water filter, garbage disposal and dishwasher along with a separate supply of cold and hot water.

The sink is connected to a strainer the fitted into sink hole using a plumber's putty. The strainer further connects to the drain tailpiece and then the rest of drainage system. If a garbage disposal is added to the system, the strainer is also connected to that.

Below it, a rubber gasket, metal washes and retainer is used to hold the sink body together.

Following are some of the features of the kitchen sink plumbing:

  • Tailpiece that is mounted on the strainer using a threaded coupling.
  • Slip up joints that connect the tailpiece to the drain trap and a threaded nipple.
  • An Escutcheon that is usually placed behind cabinets is used to hide the connector and the threaded nipple.
  • One of the main kitchen plumbing problems is to keep the sewer gas from entering the kitchen. A trap is connected to the drain tailpiece that keeps some water help back to prevent sewer gas from entering the kitchen.
  • Rubber Washer is used to provide a watertight seal.
  • Plumber's putty: You may need a plumber's putty for installing the sink. It is sealing compound that is used to make watertight seals but isn't needed if the sink comes with a rubber gasket.

It is recommended to hire a plumber for kitchen sink installation since plumbing in the kitchen's sink is not a really easy job. A plumber understands the kitchen plumbing problems better than you can.

Garbage does not spare any kitchen, so installing a proper garbage disposal is also important. It is one of the most important kitchen plumbing problems. Here's how to effectively install a garbage disposal system.

Garbage Disposal

A garbage disposal is to make the dishwasher duty easy. This is how you can install a garbage disposing system at home:

  • Remove the p-trap from the drain assembly of the sink.
  • Place a pan below the sink contain water spills while the drain is being removed.
  • Roll the plumber's putty into a 3/8″ diameter and wrap it around the flange gasket.
  • Clean the sink drain opening and insert the flange on top of the sink and attach the fastening system under the sink.
  • Apply some pressure on the flange gasket to it in place while the fastening system is being attached.
  • Under the sink the mounting plate is attached to its side and the screws are carefully fastened.
  • Now comes the tailpipe. The tailpipe is attached to a rubber seal and placed on the side of the disposal unit using a metal ring.
  • Attach the P-trap to the disposer by cutting it with a PVC or any suitable tool like a hack saw.

By following the following steps you can assemble the disposal unit and connect it to the drain system. Which is then attached to the sink.

Now while assembling the whole plumbing, the pipes are the most important part and it is important to know which pipes are to be used.

The most common pipes used for plumbing in the kitchen are PVC pipes. They are perfect for supplying cold and hot water and for sink drain systems. Other kind of pipes might not be ideal for hot water and other problems. They come in different sizes and widths depending on their application. PVC pipes are cheap, easy to install and come with a long durability!

garbage disposal under sink
Image credit: Kitchen Infinity Photo

Water & Gas For Your Home

Understanding the kitchen plumbing problems isn't as hard as it is believed to be. Plumbing emergencies can happen any time so it is important to know how everything works in case a professional plumber isn't available.

The detailed overview of the plumbing process ends here but plumbing is not a really easy job especially while trying to manage high water pressure, sewer gases, or problems with your water heater.

It is always recommended to hire a professional plumber for the job but you can use our guide to learn more about how it's done and do a DIY in case of plumbing problems and save yourself a lot of money on minor repairs.

Dino Paccino

Dino Paccino

Dino is a lifelong writer and home improvement specialist. He enjoys bringing cutting-edge information on home renovation and remodeling to Kitchen Infinity.

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