How to Install a Water Hammer Arrestor to Stop Banging Pipes
About This Project
This guide provides comprehensive, step-by-step instructions for installing a water hammer arrestor to eliminate the loud banging or hammering sound that occurs in water pipes. The noise, known as water hammer, is caused by the shockwave created when a valve closes abruptly. This project involves shutting off the main water supply, draining the lines, cutting into the problematic water line, installing a tee fitting and the arrestor, and then testing the system.
Best for advanced DIYers and professionals with basic plumbing knowledge and familiarity with power tools.
Tools & Materials
Milwaukee 1/2 in. Close Quarters Tubing Cutter 48-22-4260
Husky 1-5/8 in. Inner/Outer Reamer and Deburring Tool 410-248-0111
FASTCAP Black Long Nose Pattern Marker FC.LNM
Wilkins 1/2 in. Copper Water Hammer Arrestor 1260XL-A
QUICKFITTING 1/2 in. Push-to-Connect Brass Tee Fitting LF814R
Bucket
Milwaukee 1/2 in. Close Quarters Tubing Cutter 48-22-4260
Milwaukee Close Quarters Tubing Cutters are optimized for tough cuts in tight spaces. The compact design allows access to the tightest spaces. Chrome rollers deliver best in class rust protection while
Husky 1-5/8 in. Inner/Outer Reamer and Deburring Tool 410-248-0111
Husky's Inner/Outer Reamer removes burrs from the inside and outside of copper, steel, iron and brass piping and tubing from 1/8 in. up to 1- 5/8 in. diameter. It delivers easy, clean inside diameter reaming and outside diameter beveling. The reamer features a textured body for firm gripping. Precision-ground cutting blades result in smooth surfaces. Husky's Deburring Tool removes burrs from metal or plastic pipe edges resulting from cutting, drilling, grinding or milling tasks. Boasting a lightweight design, this contoured, hex-handled tool creates smooth surfaces for any project. The blades are easy to replace using the push button blade release. Includes two types of blades: the black deburrs aluminum, copper and PVC pipes while the silver deburrs brass and cast-iron pipes. Built to last and backed by the Husky lifetime warranty.
FASTCAP Black Long Nose Pattern Marker FC.LNM
Fast Cap Long Nose Pattern Marker solves all your tricky layout problems. It has a 1-1/8 in. in long fine point tip for marking inside holes and along walls while the other end has a wide tip for general
Wilkins 1/2 in. Copper Water Hammer Arrestor 1260XL-A
The 6-1/4 in. x 7/8 in. 1260XL-A Water Hammer Arrestor with 1/2 in. MNPT thread and 1 - 11 fixture unit capacity is used in a mixture of residential, commercial, and industrial water line applications
QUICKFITTING 1/2 in. Push-to-Connect Brass Tee Fitting LF814R
QUICKFITTING's patented technologies offer a full range of high-quality plumbing fittings and valves that are quick and easy to install. Our push-on fittings are reusable, durable, permanent plumbing connections, and get the job done 90% faster than traditional methods, including soldering. Our quick connection technology provides a simpler, safer, and a more cost-effective solution for connecting Copper, PEX and CPVC piping in plumbing and heating applications. No open flames or sealants needed, just quickly clean and debur the end of the pipe, then push to connect the fitting. We raise the industry bar for push connect technology by continuing to develop and test our products to provide superior performance. Removal of our push fittings is effortless with our disconnect tool. QuickFitting is a US-based company with a portfolio of over 100 patents and counting, and our products are backed by a 75-year warranty.
Bucket
Ideal for carrying or storing liquids.
Steps
Identify the Source and Gather Materials
20 minsFirst, you must pinpoint the exact cause of the water hammer. Operate your home's water-using appliances one at a time. The noise will occur when the appliance's water valve closes quickly. The most common culprits are washing machines and dishwashers. Once you've identified the source (assumed to be the washing machine), gather the necessary tools and supplies. You will need a water hammer arrestor with a threaded connection and a push-to-connect tee fitting that matches the diameter of your copper pipe (typically 1/2 inch). Also gather your pipe cutter, deburring tool, and a marker.
Shut Off Water and Drain the System
15 minsLocate the main water shut-off valve for your entire house. It is typically found in the basement, a utility closet, or near the water meter. Turn the valve clockwise until it is fully closed. To drain the remaining water from the pipes, go to the lowest level of your home (like a basement sink or outdoor spigot) and open the faucet. Also, open the faucets near where you will be working. Water will drain out, de-pressurizing the system. Place a bucket and some old towels under the work area to catch any residual water when you cut the pipe.
Cut the Water Line
25 minsIdentify a straight section of the copper pipe leading to the washing machine's shut-off valve. You will need to remove a section of pipe roughly 1-2 inches long to accommodate the tee fitting. Use a tubing cutter for a clean, square cut. Place the cutter on the pipe, tighten it slightly, and rotate it around the pipe, tightening the knob after each rotation until the pipe snaps. Make a second cut to remove the small section. After cutting, use a deburring tool or a file to clean both the inside and outside edges of the cut pipe ends. The pipe must be smooth and free of burrs for the push-to-connect fitting to seal properly.
Install Tee Fitting and Arrestor
20 minsFirst, prepare the water hammer arrestor by wrapping its male threads with 3-4 layers of plumber's tape in a clockwise direction. Then, screw the arrestor into the threaded female port of the push-to-connect tee fitting and hand-tighten. Give it a final quarter-turn with an adjustable wrench. Next, take the push-to-connect fitting's depth gauge (or use a ruler) and mark the insertion depth on both ends of the cut copper pipe with your permanent marker. Firmly push one side of the tee fitting onto one end of the pipe until it clicks and reaches the depth mark. Repeat for the other side. Ensure the arrestor is oriented vertically for best performance.
Restore Water and Check for Leaks
20 minsDouble-check that all your new connections are secure. Close all the faucets you opened earlier. Go back to the main water shut-off valve and turn it on slowly, counter-clockwise. You will hear the pipes filling with water. Once the valve is fully open, return to your work area with a flashlight and a dry rag. Carefully inspect the new tee fitting and all connections for any signs of dripping or moisture. Wipe the connections dry and watch them for a few minutes. If everything is dry, run the appliance (the washing machine) through a cycle to test the system under pressure and confirm that the loud banging noise has been eliminated.
Common Problems
A ProPress tool is a specialized and expensive piece of equipment. Push-to-connect (e.g., SharkBite) fittings are a more common DIY-friendly alternative.
Solution: To avoid this issue: Be mindful of this warning and take appropriate precautions.
Pipes bang and leak after installation due to misaligned or improperly sized fittings.
Solution: Dry fit all connections before soldering or crimping any connections.
Leaky pipe connections after installing the shut-off valve.
Solution: Use Teflon tape or pipe sealant before soldering the fittings on the shut off valve.
Restricted water flow due to an unremoved stiffener.
Solution: Removing the stiffener is crucial for maximizing water flow in copper pipe installations.
Failing to deburr a copper pipe can scratch and damage the O-ring inside the fitting, causing a leak.
Solution: To avoid this issue: Be mindful of this warning and take appropriate precautions.
Soldering involves an open flame. Use a heat shield and have a fire extinguisher nearby. Ensure the area is clear of flammable materials.
Solution: To avoid this issue: Be mindful of this warning and take appropriate precautions.
Leaky or weak pipe joints due to poor solder adhesion.
Solution: Thoroughly clean and apply flux to all copper surfaces before soldering to ensure a strong joint.
Frequently Asked Questions
How do I accurately identify the source of water hammer before installing the arrestor?
Listen carefully for the banging sound when a specific faucet, toilet, or appliance (like a washing machine) shuts off abruptly. You can also try gently touching the water lines near suspect fixtures to feel for vibrations when the noise occurs. Installing the arrestor as close as possible to the identified source will yield the best results.
What crucial safety steps must I take before cutting into the water line?
Always turn off the main water supply to your entire home first. Then, open the lowest faucet in your house (e.g., in a basement or outdoor spigot) and the highest faucet to completely drain the water from the pipes. This prevents unexpected water leaks and potential injury while you work.
Do I need special tools to cut copper pipes, and how do I ensure a leak-free connection?
Yes, a copper pipe tubing cutter (e.g., AUTOCUT 1/2 in.) is essential for a clean, straight cut. After cutting, use a reamer and deburring tool (like the Husky 1-5/8 in.) to smooth the pipe's interior and exterior edges. This deburring step is critical for proper sealing and preventing leaks, especially with push-to-connect fittings.
What's the best way to prevent leaks when installing the tee fitting and water hammer arrestor?
Ensure the pipe ends are perfectly clean, smooth, and free of scratches or burrs. Use a depth gauge (like the Tectite Depth Gauge) to mark the correct insertion depth on the pipe for push-to-connect fittings, ensuring it's fully seated. For the arrestor's threaded connection, apply several wraps of PTFE plumber's tape (Harvey 1/2 in. x 260 in.) clockwise to the male threads before tightening.
Is this project suitable for a beginner, and what's a realistic time estimate?
While rated 'beginner' for DIY, this project involves shutting off water and cutting pipes, so comfort with basic plumbing tasks is helpful. The estimated time is 3 hours, but allow yourself extra time, especially if you're new to working with copper pipes, to ensure all steps are done carefully and correctly to avoid leaks.
What should I do if the banging noise doesn't completely stop after installing the arrestor?
First, meticulously re-check all connections for any leaks. Ensure the arrestor was installed as close as possible to the specific fixture causing the water hammer. If the problem persists, you might have multiple sources of water hammer or need to install additional arrestors on other hot and cold water lines in your system.