Do You Need Plumbers Tape For Shut Off Valves?

An important invention for plumbing is one that often doesn’t even get touched all to often, and that is the shut off valve.

We use it when leaks occur, when servicing fixtures and water supply lines is needed and even just to prevent outdoor taps from freezing up in the winter time.

So, do you use plumbers tape on shut off valves? Typically no, but it will depend heavily on the valve itself. Most household valves come with a rubber washer that acts as a water tight seal rendering the tape useless and compression valves will use ferrules to create that seal.

Creating a water tight seal is of utmost importance to a plumber and the result is peace of mind for a homeowner.

Improper sealing can lead to leaks, which over time can potentially cause severe water damage. Stick around to learn more about the sealants of shut off valves in your home!

When Do You Require Plumbers Tape?

Plumbers tape has been another great introduction to the plumbing world and has solved many leaky issues in plumbing systems.

This stretchy tape with a scientific name I won’t even begin to try and spell out here works by being wrapped about 2 times around the thread of a fitting.

As fittings tend to be made of either plastic, steel or brass, their connection to each other tends to leave really small gaps. These gaps can lead to leaks occurring, that range from aggressive drips to the more dangerous slow dripping.

Slow dripping is more dangerous as it is often the one that goes unnoticed and can lead to extensive water damage over time.

Plumbers tape works by stretching over these threads to allow them to compress the tape down filling in those little gaps to create a perfect water tight seal.

You typically require this tape whenever there is a threaded connection that does not have a rubber gasket, washer or ferrule already in place.

Common places you would find plumbers tape being used:

  • Shower head – Both sides of the chrome (or other material) pipe that threads into the fitting inside of the wall as well as the head itself require plumbers tape
  • Water heater – The cold water inlet, as well as the hot water outlet both require plumbers tape around their threads
  • P-trap with broken washer – Typically p-traps already have a washer, but when the washer breaks or cracks, adding tape to the threads of the fitting will create the seal

The Different Types Of Shut Off Valves

Toilet shut off valve

There are actually quite a few different types of shut off valves that can be found in the home and can be shaped differently, made of different materials and function differently.

You have shut offs for your kitchen and bathroom sink, shutoffs for a shower, water heater, water softener and of course, the most important main shut off valve for your whole house.

Kitchen & Bathroom Shutoffs

Bathroom sink shut off valves

Typically these valves are going to be smaller in size and made of steel, but can be found in brass.

They are installed in your showers and sinks for the purpose of being able to cut the supply of water off to the specific fixture.

Cutting the supply of water off allows you to disconnect or work on a fixture without needing to shut the water to the whole house down and then draining out the remaining water in the lines.

More often they are just found under the sinks and to the toilet. If work was done on a shower recently, the plumber might have installed them there, but typically showers don’t have them as they are behind the drywall and tile.

A toilet and a faucet are fixtures that require maintenance or to be repaired somewhat frequently (every 5-10 years) so having a shut off installed just makes sense.

These valves can be made to accommodate PEX, copper and CPVC:

For Copper

For copper pipe, the shut off valve can either come as sweat (meaning it can be soldered) or compression, which involves the use of a nut and ferrule that tightens down over top of the pipe to create a seal.


Typically PEX will either require a crimping system where the valve fits into the pipe and a ring fits over top of the pipe and a special tool is used to cover the ring and clamp down on it to create the seal.

Another form of PEX utilizes a tool that expands. The head of the tool fits into the PEX pipe, expands while wedging its way in and then a fitting gets placed into the pipe while the pipe comes back to its original shape, creating a water tight seal.


CPVC pipe will require a CPVC specific shutoff valve. This valve can actually be made of steel, but is specially designed to have CPVC on the inlet of it to allow for bonding between pipe and fitting via CPVC cement.

CPVC can also can utilize a threaded connection, where the fitting will get screwed into place.

The main two types of valves found in a home plumbing system are:

Ball Valves

A ball valve is a common valve you’ll find on your water heater and even your main shut off valve.

This valve only requires a quarter turn and has a ball internally that can either block off the flow off water when closed, or let water through it’s hole when it’s turned open.

This type of shutoff may require plumbers tape around the threads that connect it to piping or other fittings, but not for the shut off portion itself.

Compression Valve

A compression valve is one of the oldest styles of valve and it uses a spinning motion to screw down a washer into what’s known as a “seat”. This creates a water tight seal when fully closed.

When Should You Not Use Plumbers Tape?

Because copper is among the more popular choices even to this day when installing water supply lines into a home, it is best to take precautions when using plumbers tape around soldered joints.

Soldering is the process of heating up the copper to such a degree that a softer alloy (solder) can melt between it’s pipe and fitting. This creates a water tight seal.

Plumbers tape will melt and is recommended to never go close to heat. When installing a female fitting onto a hot water tank, which requires plumbers tape, it’s best to cut a short piece of pipe (around 6 or 7 inches) and solder the pipe to the fitting separately.

Then, you can wrap your plumbers tape around the male threads on the water heater and once the female fitting and pipe are cooled off, then you can thread the two together.

How Many Times Do You Wrap Plumbers Tape Around A Fitting?

The trick with plumbers tape is you want there to be enough to satisfy a water tight seal, but not too much so that you can’t even get the fitting on properly.

Generally, you should try and wrap each fitting with plumbers tape with two full rotations around. No more, no less.

  • Grab the tape by the roll
  • Position the tape so that the outside of the tape is what will make contact with the fitting – When you wrap this way, it puts resistance on the tape itself as you’re spinning it around the fitting giving you much more control
  • Wrap a maximum twice around the pipe and in the clockwise direction in relation to the end of the pipe being closest to you

I wrote another blog titled “what is the purpose of plumbers tape?”. Go check that post out for lots more helpful tips and advice related to this kind of material. You can find it by clicking here!


Tyler Takacs

My name is Tyler, I live in Ontario Canada and enjoy learning about common plumbing issues in the household. I have spent just over three years in the trades as a plumbers apprentice, but am now onto a less physical job. I still enjoy studying and learning about my own house's plumbing as well as finding ways to help others with their issues.

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