John Guest Quick-Connect and SharkBite Fittings: Are They Reliable?

Posted by John Woodard on July 23, 2021

Quick-connect fittings and push-to-connect fittings make plumbing fixes and installations simple and efficient. With a John Guest quick-connect or a SharkBite push-to-connect, you can fix a leaking plastic pipe or copper pipe in minutes without calling a plumber, soldering, or replacing the entire pipe. Plumbers have used John Guest fittings for decades, but SharkBite fittings are newer to the market and their dependability is still under scrutiny.

We're here to tell you if John Guest quick-connect and SharkBite fittings are reliable or a bad idea and when you should use them. 

Anatomy of quick-connect and SharkBite fittings

John Guest and SharkBite fittings have a similar construction, but slight differences in design make them suitable for different uses. Both quick-connect and SharkBite fittings have a collet and an O-ring within the body. The metal teeth that make up the collet grip a pipe or tubing for a secure hold. The O-ring provides a secure seal to prevent leaks. Both quick-connect and SharkBite fittings are made to install quickly, create a durable seal, and attach to PEX or PVC tubing or copper pipes.

Design of a SharkBite fitting

SharkBite fittings

Brass body: SharkBite fittings are made of lead-free brass, which gives them a higher temperature and pressure tolerance than plastic quick-connect fittings. The material prevents a SharkBite fitting from cracking in freezing temperatures and makes them the ideal fitting for copper pipes. 

Push-to-connect design: When you push a SharkBite fitting onto a pipe or piece of tubing, the teeth clench down. They must be pushed out of the way using a disconnect tool to release them.

sharkbite teeth

Ring of teeth: A SharkBite fitting has many little teeth around a collet that grips the pipe or tubing and hold it in place. 

Plastic spacer: This removable insert moves the collet so the tubing locks down and prevents the tube from backing out. 

Design of a John Guest Quick-Connect fitting

John Guest fittings

Plastic body: The plastic material of a quick-connect is ideal for plastic tubing since they are both flexible and will give with one another. 

Twist-lock design: This locking mechanism prevents the connection from coming apart when you turn a faucet off, causing the flow to come to an abrupt stop. Because of the twist-lock, the teeth tighten their grip when you try to pull a quick-connect fitting off. 

quick-connect collet

Ring of teeth: The collet of the John Guest fitting also has little teeth that grip tubing, but the quick-connect has fewer teeth than the SharkBite.

Removable collet: You can disassemble a quick-connect fitting, unlike a SharkBite fitting. This allows you to repair the fitting if needed.

When to use a John Guest Quick-Connect or SharkBite fitting

Where to use SharkBite fittings

SharkBite fittings are the best fitting for installing a hot water heater because of their ability to withstand high temperatures. SharkBites work better than plastic quick-connects on copper pipes because the lead-free brass body is rigid like the pipe and has a higher pressure tolerance. If you need to repair or replace copper plumbing in your home, a SharkBite fitting is an excellent choice. 

Sharkbites are approved for use underground and behind walls, but installing them there could be risky. In both places, the fitting would be out of site. You would have no way of knowing if it were to start leaking. A SharkBite fitting contains a rubber O-ring, which is not best for permanent connections. We don't recommend using a SharkBite fitting outside because sunlight can dry out the rubber O-ring and cause it to crack or split. 

Where to use John Guest Quick-Connect fittings

Quick-connect fittings work better than SharkBites for plastic tubing because of the fitting's flexibility. John Guest quick-connects are great for smaller diameter tubing, often used for filter installations. The smaller fittings are interchangeable with compression fittings. The black John Guest fittings are UV resistant and can be used outside.

Installing a Quick-Connect or SharkBite fitting

measuring pipe depth

John Guest quick-connect and SharkBite fittings do their jobs well. Usually, leaks occur because a fitting was not installed properly, not because the fitting fails.

Do's and don'ts

  • DO cut the pipe properly with a pipe cutter, but...
  • DON'T use a hacksaw. Using a hacksaw creates burs or scratches that prevent the O-ring from sealing.
  • DO push the fitting in all the way.
  • DO make sure you have the proper size disconnect tool
  • DO make sure you have the correct side of the disconnect tongs facing up. Otherwise, the fitting won't fit into the tool.
  • DON'T use bent tubing. If you side-torque the tubing, it won't seal properly.
  • DON'T use a scratched or dirty pipe or tube, but...
  • DO clean it first to ensure a secure O-ring seal.

Is a SharkBite fitting reusable? What about a quick-connect?

SharkBite disconnect tools

You can disconnect a SharkBite fitting using a disconnect clip or disconnect tongs. You can disconnect a John Guest fitting without any tools. Quick-connect and push-to-connect fittings are not permanent, but should only be reused for temporary installation. The lubricant on the collet of a SharkBite wears off after a while, and the O-ring of either fitting may stretch or wear out. Quick-connect fittings are better suited for reuse than SharkBite, but we've reused SharkBite fittings without any problems. 

Pros and cons of Quick-Connect and SharkBite fittings

sharkbite cpvc pipe

  • Increased speed and efficiency- eliminates the need to wait for all of the water to drain from the pipe
  • Great for emergency fixes- simply remove with a disconnect tool and press or lock a new one into place
  • No fire hazards- no risk of singeing or catching something on fire compared to soldering 


  • PRO: structural stability
  • PRO: designed for copper pipe
  • PRO: greater temperature and pressure tolerance
  • CON: not repairable (collet can't be removed)
  • CON: expensive 

John Guest Quick-Connect

  • PRO: works great with plastic
  • PRO: can be disassembled for repair
  • PRO: inexpensive
  • CON: doesn't work as well on copper 
  • CON: the hotter the water, the lower the pressure tolerance

Are John Guest quick-connect and SharkBite fittings a bad idea or are they reliable?

John Guest and SharkBite are now both part of the Reliance Worldwide Corporation (RWC), along with, Cash Acme, HoldRite, and Streamlabs. We spoke with Nathan Curry, our friend from John Guest, to get his inside perspective on Quick-Connect and SharkBite fittings. Nathan described Sharkbite as, "an innovative, aggressive, and growth-oriented" company who has experienced great success since it's first year on the market.  He explained how SharkBite "got their fittings into people's hands and let them try them out." Nathan shared that people trust SharkBite because it combines easy push-connect technology with a strong brass body.

John Guest quick-connect and SharkBite fittings are both reliable and awesome fittings for emergency fixes. Even though Quick-Connect and SharkBite fittings are rated for use underground and behind walls, soldering pipes may be the smarter choice. It's important to keep these fittings somewhere visible and easily accessible in case they were to leak. But in our experience, leaks are usually the result of improper installation. Both quick-connect and SharkBite fittings provide strong connections, and we are confident in their dependability. 

Learn more about how quick-connect fittings work or how to measure fitting thread type. 


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