How To Connect Two Faucet Supply Lines

How To Connect Two Faucet Supply Lines

You don’t need to be a professional plumber to complete tasks on your drains. One such task is connecting faucet supply lines. In this quick guide, we’ll walk you through the steps on how to connect two faucet supply lines.

When learning how to connect two faucet supply lines, keep a few things in mind. First, you want to ensure a leak-free connection. Second, you want to have the right tools on hand to get the job done. Third, you always want to make sure to inspect your work when you are done.

Read on for detailed steps on how to connect two faucet supply lines at home yourself.

Connecting Faucet Supply Lines

Faucet Supply Lines
Source: SvetMedvedeva

Ensuring leak-free connections is the priority every time you work on your pipes and connections. Connecting two faucet supply lines requires no special skills, but a lot of care is necessary to prevent leakage.

Also, you don’t need any special tools to get this job done. Your hands are more than enough to complete this task. However, if you need to work in tight spaces, you may need a basin wrench.

Here is how to connect to faucet supply lines:

Using Compression Fittings

Connecting two faucet supply lines is best done using a compression nut fitting. The easiest way to do this is to measure the pipe and purchase a compression fitting that matches the size.

Joining the lines to the fitting may involve different procedures depending on specifications, but it is never complicated. Most times, it involves straightforward insertion and twisting.

While there are various compression fittings for different uses, the ideal option for faucet supply lines are standard fittings. That’s because they do not require any modifications to use. In addition, compression fittings are easy to install and come with directions for use.

  • Begin by fixing the compression fittings to the supply line, making sure the threads of the nut face the valve
  • Put the compression ring around the supply line
  • Let the end of the supply tube fit into the valve, making sure it fits well
  • Ensure that the supply line fits nicely to prevent leakage
  • Make sure the compression ring is fitted correctly
  • Push in and twist to ensure proper connection

Compression fittings are simple enough to make, and they are the easiest ways to connect a faucet supply line.

However, they come with a little disadvantage. A compression fitting often causes leakage and is not resistant to heat and water pressure. Although they are easy to maintain and install, they may be prone to damage as well.

Connecting Faucets To Supply Lines

Here is how to connect your faucet to supply lines:

  • Measure the distance between the faucet and the valves. You need to add some inches to make room for turning and twisting
  • Ensure that your supply lines fit into the valves
  • Shut off the main water supply line
  • Attach the supply connectors to the faucet
  • Label the two supply connectors “hot” and “cold” to help you attach them correctly
  • Tighten the faucet to the sink
  • Connect the hot and cold supply lines to the shutoff valves. The line for the hot water is red, while the blue is for cold water. You will need an adjustable wrench to make a firm connection
  • Turn on the water to test for leaks. Once there are no leaks, your work is done. If there are leaks, retighten the spaces and try again

How Tight Should The Connection Be?

Ideally, you want the supply lines to be tightly connected. It should be tight enough to hold the pieces in place as well as prevent leakage. However, make sure you don’t overtighten the supply line, as that can weaken the connection. It should be accessible enough that when using a wrench, you can effectively loosen it before a turn goes the entire cycle.


Learning how to connect two faucet supply lines and actually getting it done is not difficult. You don’t even need any tool in most cases. All you need to do is follow the instructions in this guide. With a little bit of practice, you should be able to achieve watertight connections, even if you are not a professional plumber.

Frequently Asked Questions

What size is a faucet supply line?

Typically, the main water pipe that comes off the main water supply line measures 3/4 inches in diameter. Other branch lines that supply the various fixtures have a diameter of ½ an inch.

How do you connect two sink hoses together?

A coupler is your best bet when connecting two sink hoses. The coupler is made up of a barbed rod that fits inside both sink hoses and rings. The rings crimp the hoses onto the rod. Make sure both hoses have the same diameter before attempting to join them.

How do you extend a faucet supply line?

Turn off the water supply line and get rid of any existing broken extenders. Label the hot and cold extenders appropriately, especially if they don’t come with any markings. Attach the connectors to the faucet body, and then attach the faucet to the sink. After connecting other components, such as the tailpieces, connect the extenders to the supply lines. Tighten them with an adjustable wrench.