What Size Supply Line Does A Moen Faucet Need?

It is frustrating to find out that your Moen faucet is malfunctioning due to its supply line having an issue. You seem to be wondering what size Moen faucet supply line to buy and replace it. Wonder no more! We did in-depth research on this topic, and here's what we've discovered.

Moen faucets use a supply line of 1/2 inch Iron Pipe Size (IPS). You will also need compression fittings of 3/8 inches to connect two Moen faucet lines securely.

That was straightforward enough, right? Well, keep reading as we continue to discuss the correct pipe for your Moen faucet. We will also share with you the installation setup. So stay with us until the end!

Damaged leaking water tap hose in the bathroom of house, flat or other place. Plumbing concept. - What Size Supply Line Does A Moen Faucet Need

The Moen Faucet Supply Line Size

Drain pipe or sewer under sink. stainless steel pipe.

A faucet line or water supply line may come in metal or plastic to deliver water demand to other home fixtures. For safety and precautionary reasons, it needs to be in the right size to carry the water across the lines quickly.

Your Moen supply line size may vary in faucet models and home water piping design. Typically, it uses a supply line of 1/2 inch IPS. It also has compression fittings relative to the Moen faucet supply line. For this instance, if the faucet supply line size is about 1/2 inch, it requires 3/8 inches of compression fittings. This prevents the faucet line not to burst out and to cause flooding in your home.

Is There A Standard Size For Water Supply Lines?

There are plumbing standard regulations when installing a fixture supply line. For example, in Alabama, a water supply and distribution code show the ideal size of the water supply pipes. Use a faucet water supply pipes according to this code where fixtures, water flow, and usage rate are identical. Thus, you can safely use a 1/2-size supply line for your faucet.

Following this code will avoid potential issues that may cause your Moen faucet to function ineffectively. Note that this code may vary between cities and states and might change depending on your local building code.

What Pipes Do Faucet Supply Lines Use?

There are plenty of pipes that you can find in the plumbing supply store today. You should know that faucet supply lines and their materials come in a variety. Also, these pipes are made specifically for their intended use.

Here are the standard faucet supply lines that you can use:


Flexible copper pipes are synonymous with copper supply pipes. It is closely similar to the factory-attached lines as it uses copper supply pipes as well. Moreover, as you notice, you can also find this pipe in most HVAC freon pipes.

copper pipes and fittings for carrying out plumbing work. Plumbing, fixing pipes and fittings for connection of water or gas systems

Copper pipes are well known for their features with high corrosive resistance. This makes them at the faucet, or HVAC pipes resist damaging elements.


The most promising tubing product you will see in the market is braided pipes. From the word itself, this pipe looks like a braided hair design but in steel or stainless wrappings. This makes this pipe very flexible and great for a challenging pipe setup.

Get this braided supply line on Amazon.


As you notice, when you open the packaging box of your newly bought faucet, you will see a set of faucets along with attaching lines. Usually, this is the pipe or lines that the faucet company includes in its marketing. You can apply this in a hot and cold water supply setup. The material is copper, commonly used in most plumbing water supply systems.

Other Faucet Rated Pipes

As you might not know, other pipes are rated for plumbing pipe installation. These pipes utilize materials that offer safety and resistive properties to prevent early failure.

Here are the other pipes that are also rated for faucets:

  1. Cast iron and galvanized steel pipes.
  2. Polyvinyl chloride pipes (PVC) pipes.
  3. Cross-linked polyethylene (PEX) pipes.
  4. Acrylonitrile butadiene styrene (ABS) pipes.

What Are The Signs Of A Malfunctioning Moen Faucet?

Moen showcases their advanced and unique pull-out faucet design. However, this doesn't mean it's free from leaking or other problems. You must quickly address its underlying issue to prevent early symptoms from developing that might lead to a costly repair.

Here are the Moen faucet possible failing signs:

Won't Stay On

If you observe that the Moen faucet won't stay on, this might be due to its cartridge having too much grease. During manufacturing, Moen applied special silicon or grease to the cartridge to quickly switch the faucet ON and OFF.

Water tap , faucet. Flow water in bathroom with sink. Modern clean hause. Backround hygiene. Panorama

If too much grease is present in the cartridge, this causes the cartridge to switch OFF on its own. You can avoid this issue by checking the cartridge and cleaning the excess grease.


One of the common issues you will undoubtedly experience in Moen faucets is a leak. Over time, the Moen faucet's vital components, such as the O-ring, undergo wear and tear.

O-rings in faucets are crucial in preventing water from leaking out from the spout base. If you see water leaking from the Moen faucet's spout base, likely its O-ring has become bad. You can only fix this problem by complete replacement.

How To Replace The Moen Faucet O-Ring

Since the O-ring keeps water from coming out at the spout, you must replace it before using the faucet again. It is impossible to avoid wearing down the Moen faucet O-ring, but luckily replacing it is not a complex task.

Before you start fixing the faucet, you may need to prepare the following things:

  • Pliers
  • Gloves
  • Vinegar
  • Hex key
  • Screwdriver
  • New cartridge and O-ring

Get this O-ring kit on Amazon.

Once everything is ready, you can start fixing the faucet using this guide below:

  1. Switch OFF the water supply.
  2. Pull out the cap of the faucet handle to expose its screw.
  3. Loosen the screw using your screwdriver and remove it with its handle.
  4. Remove the hex nut using your hex key. If the hex key doesn't work, use pliers to remove it.
  5. Detach the faucet collar by rotating it counterclockwise. You can easily detach it by wearing a glove.
  6. Remove the faucet stem. Use a plier to increase your grip and quickly pull it out.
  7. You should see the faucet's cartridge and the O-ring. Remove the O-ring and replace it with the same O-ring size.
  8. Check the faucet's body along with its other components if there is visible debris. Apply vinegar to loosen dirt elements in the faucet parts.
  9. Replace the bad O-ring and reinstall it accordingly to the faucet body.
  10. Use the screwdriver to securely tighten the screw that holds up the faucet and the handle.

Conduct further inspection to verify that you successfully fix your Moen faucet using the above steps.

How To Attach The Kitchen Faucet Supply Lines

In every home water piping remodeling, removing pieces of the project is the easiest part of the job. However, connecting the faucet supply lines may be the case isn't the same.

We listed below how you can link your kitchen faucet supply line correctly to avoid unnecessary failure.

Here's how you do it:

  1. First, begin your work by measuring the distance of your faucet from the water supply valves and their opening.
  2. Use only a supply line proportionate to your Moen supply line size. For this example, you should get a 1/2-inch size supply line.
  3. Ensure to inspect both the supply line and the kitchen faucet opening thread ends are free of dirt.
  4. Run enough seal tape in both the faucet supply opening and supply valve.
  5. Now link the supply lines to the kitchen faucet openings.
  6. Use an adjustable wrench to tighten the supply lines nut to the faucet register securely.
  7. You can now link and tighten the hot and cold water supply lines to their designated valves.

The key to successfully performing this guide is to be patient at all times. Don't rush anything to avoid irreversible failure, which can cause expensive repairs.

Damaged leaking water tap hose in the bathroom of house, flat or other place. Plumbing concept.

To Wrap Things Up

We've discussed the size of the supply line that the Moen faucet uses. We also addressed the ideal pipe for a Moen faucet supply line and went through the common signs of a malfunctioning Moen faucet. Further, we also shared the easy steps to fix your Moen faucet's bad O-ring. We hope you will use this information to maintain your Moen faucet well.

If you like reading this article, kindly consider our other posts below:

Grohe Vs Moen Vs Kohler: Which Faucet Is Right For You?

How To Install A Moen Widespread Bathroom Faucet [Step By Step Guide]

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