What is water hammer? Water hammer is a shockwave that travels through your plumbing system, causing that jarring bang or thud you hear after a faucet is turned off. Can I fix it myself? Yes, in many cases, you can fix water hammer yourself with a few simple tools and techniques. Who is affected by water hammer? Anyone with a plumbing system can experience water hammer, especially if they have older pipes, quick-closing valves, or high water pressure.
That sudden, violent pipe banging can be startling, even alarming. You might be in the shower, and the moment you turn off the tap, a loud thwack echoes through your home. This disruptive sound is known as water hammer, and it’s more than just an annoyance; it can also put undue stress on your plumbing system, potentially leading to leaks or damage over time. Fortunately, there are several effective and surprisingly easy ways to fix water hammer pipes today. Let’s delve into the causes and discover straightforward solutions to reduce water hammer and silence those loud pipes.
Deciphering the Cause of Water Hammer
Before we can effectively fix banging pipes, it’s crucial to grasp the cause of water hammer. Imagine water flowing through your pipes at a good speed. When a valve, like the one on your faucet or washing machine, is suddenly shut off, the moving water has nowhere to go. It abruptly stops, and its momentum creates a pressure wave. This wave travels back through the pipe, bounces off fittings and elbows, and creates that characteristic hammering sound. It’s essentially a miniature water explosion happening within your pipes.
Several factors can contribute to or worsen water hammer:
- Quick-Closing Valves: Solenoid valves in appliances like dishwashers and washing machines, or even manual quarter-turn ball valves, shut off water flow instantaneously. This rapid stop is a primary culprit for initiating the shockwave.
- High Water Pressure: If your home’s water pressure is too high (generally above 80 psi), the water is moving with more force. This increased momentum means a more powerful shockwave when flow is interrupted.
- Air Trapped in Pipes: Air can become trapped in your plumbing system. When water flows past these air pockets, it can compress and then rapidly expand, creating surges and contributing to the banging.
- Loose Pipes: If your pipes are not securely fastened, they can vibrate and move when the shockwave hits, amplifying the noise and the water pipe vibration.
- Long, Straight Runs of Pipe: Longer pipe runs allow the water to build up more momentum, making the shockwave more significant when it’s suddenly stopped.
Easy Solutions to Silence Your Plumbing
The good news is that addressing water hammer doesn’t always require a complete overhaul of your plumbing system. Many effective fixes are DIY-friendly.
1. Installing a Water Hammer Arrestor: The Go-To Solution
One of the most effective ways to fix water hammer pipes is by installing a water hammer arrestor, sometimes called a plumbing shock absorber. These devices are designed to absorb the shock of the sudden pressure surge.
How a Water Hammer Arrestor Works
A typical water hammer arrestor is a sealed chamber containing a piston or a diaphragm and a pocket of air or gas. When the shockwave occurs, the moving water forces the piston or diaphragm to compress the air/gas pocket. This compression absorbs the energy of the shockwave, preventing it from traveling through the rest of the plumbing and causing the banging. Think of it like a tiny shock absorber for your pipes.
Types of Water Hammer Arrestors
There are a few main types of arrestors:
- Piston Type: These use a sliding piston that moves within a cylinder. The water pressure pushes against the piston, and the air trapped on the other side absorbs the shock.
- Diaphragm Type: These have a flexible diaphragm separating the water from the air cushion. As the shockwave hits, the diaphragm flexes, compressing the air.
Table 1: Pros and Cons of Water Hammer Arrestor Types
| Arrestor Type | Pros | Cons |
|---|---|---|
| Piston Type | Durable, effective in many situations, generally affordable. | Can sometimes stick if not maintained, may eventually require replacement. |
| Diaphragm Type | Silent operation, less prone to sticking, often longer lifespan. | Can be slightly more expensive, diaphragm might eventually wear out. |
How to Install a Water Hammer Arrestor
Installing a water hammer arrestor is a relatively straightforward DIY project for most homeowners. It’s best to install them as close as possible to the fixture that causes the noise, typically on the supply line.
What You’ll Need:
- Water hammer arrestor (choose one appropriate for your pipe size and connection type)
- Adjustable wrench or pipe wrench
- Pipe thread sealant or Teflon tape
- A bucket and towels (for catching residual water)
Steps:
- Turn Off the Water Supply: Locate the main water shut-off valve for your house and turn it off. Alternatively, if the noise is isolated to a specific fixture, you might be able to shut off the valve directly behind that appliance (e.g., under the sink or behind the washing machine).
- Drain the Pipes: Open the faucet furthest from the shut-off valve to relieve any remaining pressure in the system and drain the water from the pipes.
- Locate the Installation Point: Identify the supply line to the appliance or faucet that is causing the water hammer. The best spot is often where the flexible supply line connects to the rigid pipe coming from the wall or floor.
- Disconnect the Existing Supply Line: Use your wrench to disconnect the flexible supply line from the pipe fitting. Be prepared for a small amount of residual water to drip out.
- Apply Sealant: Wrap the threads of the water hammer arrestor with pipe thread sealant or Teflon tape to ensure a watertight seal.
- Install the Arrestor: Screw the water hammer arrestor onto the pipe fitting. Tighten it securely with your wrench, but avoid overtightening, which can damage the threads.
- Reconnect the Supply Line: Reconnect the flexible supply line to the outlet of the water hammer arrestor. Tighten it firmly.
- Turn On the Water Supply: Slowly turn the main water supply back on. Check for any leaks around the connections.
- Test: Operate the fixture that was causing the water hammer. You should notice a significant reduction or complete elimination of the banging sound.
2. Addressing High Water Pressure
As mentioned, high water pressure is a major contributor to water hammer. If your home’s water pressure exceeds 80 psi, it’s wise to install a pressure reducing valve (PRV) on your main water line.
Checking Your Water Pressure
You can check your home’s water pressure with a simple pressure gauge that screws onto an outdoor hose bib or an indoor faucet.
Table 2: Recommended Water Pressure Levels
| Pressure Reading (psi) | Assessment | Action Recommended |
|---|---|---|
| Below 40 | Low Pressure | May indicate other issues, not likely water hammer |
| 40-60 | Ideal Range | No action needed for pressure |
| 60-80 | Acceptable, but on the higher side | Monitor for water hammer issues |
| Above 80 | Too High | Install or adjust a Pressure Reducing Valve (PRV) |
Installing a Pressure Reducing Valve (PRV)
A PRV is a valve that automatically reduces and maintains the water pressure in your home to a safe and consistent level. Installing a PRV is a more involved plumbing task and might be best left to a professional if you’re not comfortable with major plumbing work. However, if you’re tackling it, here’s a general overview:
- Turn off the main water supply.
- Locate the main water line where it enters your house.
- Cut into the main water line and install the PRV with the arrow on the valve pointing in the direction of water flow. Use appropriate fittings and pipe thread sealant.
- Turn the water back on and adjust the PRV to the desired pressure (typically 50-60 psi).
3. Bleeding Air from Pipes
Trapped air can exacerbate water hammer. Regularly bleeding air from your system can help reduce water hammer and the associated pipe noise.
How to Bleed Air from Pipes
- Turn off the main water supply.
- Open the highest faucet in your house (e.g., an upstairs bathroom sink or bathtub).
- Open the lowest faucet in your house (e.g., a basement utility sink or outdoor hose bib).
- Slowly turn the main water supply back on.
- Listen for sputtering: Water will begin to flow from the lowest faucet, but you’ll likely hear air sputtering from the highest faucet. Let it run until a steady stream of water emerges without any air.
- Close the highest faucet first, then close the lowest faucet.
- Test: Turn on any fixtures that were previously experiencing water hammer.
You can also bleed air from individual appliances by following their manufacturer’s instructions. Some washing machine supply lines, for instance, have bleed valves.
4. Securing Loose Pipes
Loose pipes can amplify the sound of any water pipe vibration. If you can hear your pipes rattling or moving when water flows, securing them can make a big difference.
How to Secure Loose Pipes
- Locate the loose section: You might need to access your crawl space or basement to find where the pipes are not adequately supported.
- Use pipe straps or clamps: These are readily available at hardware stores. Choose straps that fit your pipe diameter.
- Attach straps to joists or studs: Use appropriate screws to securely fasten the straps to the framing of your house. Ensure the pipes are snug but not so tight that they are stressed.
- Consider insulation: Foam pipe insulation can also help dampen vibrations and reduce noise.
5. Checking and Replacing Worn Washers and Valves
Old, worn-out washers or faulty valve seats in faucets and toilet fill valves can also cause the kind of abrupt water shut-off that leads to water hammer.
What to Look For
- Faucets: If a particular faucet causes the banging, the rubber washer inside might be worn or stiff. Replacing it is a simple fix.
- Toilet Fill Valves: The fill valve in a toilet tank can also cause water hammer if its internal mechanism is faulty or if the water supply valve to the toilet is shut off too quickly.
How to Replace Faucet Washers
- Turn off the water supply to the faucet.
- Remove the faucet handle and the trim piece.
- Unscrew the valve stem.
- Replace the washer at the bottom of the valve stem with an identical new one. You might also want to check and clean the valve seat in the faucet body.
- Reassemble the faucet.
- Turn the water back on and test.
6. Installing Air Chambers (A Traditional Method)
Before the widespread use of mechanical water hammer arrestors, plumbers would often install simple air chambers to reduce water hammer. These are vertical lengths of capped pipe installed above the shut-off valve for a fixture.
How Air Chambers Work
The idea is that when water flow is stopped abruptly, some water is forced into the air chamber, compressing the air within. This compressed air then acts as a cushion.
Why They Can Fail
Over time, the air in these chambers can become absorbed by the water, rendering them ineffective. This is why modern arrestors with sealed air/gas pockets or pistons are generally more reliable. However, if you have existing air chambers and suspect they are the issue, you can try to recharge them by draining the system completely (as described in the “Bleeding Air” section) to allow air to re-enter the chambers.
When to Call a Professional
While many water hammer issues are straightforward to fix, there are times when professional help is recommended:
- Persistent Water Hammer: If you’ve tried the above solutions and the pipe banging persists, there might be a more complex issue at play, such as extensive pipework problems or a faulty main water regulator.
- Uncomfortable with DIY: If you’re not comfortable working with plumbing or lack the necessary tools, it’s always best to call a qualified plumber.
- Major Plumbing Work: Installing a PRV or addressing widespread pipe issues often requires professional expertise and tools.
- Suspected Pipe Damage: If you suspect the water hammer has already caused damage, like leaks or joint failures, a plumber can assess and repair it.
Frequently Asked Questions About Fixing Water Hammer
Q1: How often should I check my water pressure?
A: It’s a good idea to check your water pressure at least once a year, or if you notice changes in water flow or experience water hammer.
Q2: Can I use just one water hammer arrestor for my whole house?
A: No, water hammer arrestors are typically installed at individual fixtures or appliances that cause the problem. While a PRV on the main line can help manage overall pressure, specific shock absorption is best done close to the source of the sudden shut-off.
Q3: My washing machine causes the noise. Where should I install the arrestor?
A: Install the arrestor on the hot and cold water supply lines directly behind the washing machine, connecting between the shut-off valves and the machine’s hoses.
Q4: Will insulation on my pipes stop water hammer?
A: Pipe insulation can help dampen the sound of water pipe vibration and minor noises, but it won’t stop the shockwave itself. For actual water hammer, you need a plumbing shock absorber like a water hammer arrestor.
Q5: How do I know which size water hammer arrestor to buy?
A: Most arrestors are designed for standard pipe sizes (e.g., 1/2 inch or 3/4 inch). Check the connection size on your existing pipe fitting to ensure you purchase the correct one.
By taking a proactive approach and implementing these easy fixes, you can significantly reduce or eliminate water hammer, protecting your plumbing and restoring peace and quiet to your home. Silencing those loud pipes is well within your reach!