What is water hammer?
A water hammer tends to make a lot of noise, hence its moniker. The loud clangs or bangs that you hear is a result of a sudden cut off of the water flow in your pipes. This sudden stop or cut can cause a pressure spike that will then cause noise coursing through the pipes.
Water hammer should not be ignored, because it can cause leaks and burst pipes in your home. If you hear this kind of noise in your pipes, then you need to give it your attention.
Is That Really Water Hammer?
Before you blame all those pipe-rattling sounds on water hammer, it’s worth making sure what you’re dealing with. Not every clang or bang in your plumbing is the infamous hydraulic shock known as water hammer. Sometimes, the culprit is just air trapped in your pipes—which, fortunately, is much less dramatic and much easier to sort out.
Quick Test for Water Hammer
So, how can you tell? Here’s a simple way to check:
- Listen for Patterns: Water hammer usually happens right after you abruptly shut off a tap or an appliance. If the noise occurs at other times, air might be the problem instead.
- Try Flushing Out Air: Open the tap closest to your main water meter. Then, work your way around the house, opening the next nearest tap, and so on, until every tap is running. Start turning them off in reverse order. This helps flush any trapped air pockets from your pipes.
If that quiets the ruckus, chances are it wasn’t true water hammer after all—just some pesky air. But if your pipes are still auditioning for a percussion section, read on.
What is a Water Hammer Arrestor and How Does it Work?
To tackle the racket and potential damage caused by water hammer, many homeowners turn to a simple device called a water hammer arrestor. You can find these at just about any hardware store, and the best part is—they won’t break the bank (probably cheaper than a night out or, yes, even a scruffy pair of sneakers).
So, what does this gadget actually do? A water hammer arrestor is installed directly onto your plumbing where the noise and banging are worst. Inside, it contains a sealed chamber filled with air or a spring-loaded piston. When a sudden surge of water pressure slams through your pipes—say, when you quickly shut off a tap—this chamber absorbs the shock, cushioning the blow and taking the stress off your pipes. The result: quieter plumbing and less worry about leaks or bursts down the line.
Can Water Hammer Happen in Modern Pipes Like CPCV or PEX?
It’s easy to assume that newer piping materials—such as CPCV or PEX—might spare your home from the noisy headaches of water hammer. Interestingly, while these materials do tend to dampen the racket compared to old-fashioned metal pipes, the underlying pressure surges can still happen. The key difference? Sometimes, you won’t hear a peep.
That means water hammer can go undetected, quietly putting extra strain on your plumbing. Even if your walls aren’t reverberating with clangs and bangs, it’s still wise to have your pipes periodically checked—especially if you’ve recently switched over to modern materials. Silent or not, unchecked water hammer risks causing the same sorts of leaks and long-term pipe damage as its noisy cousin.
Water hammer should not be ignored, because it can cause leaks and burst pipes in your home. If you hear this kind of noise in your pipes, then you need to give it your attention.
But what are the sources of water hammer? There are a lot of them, including:
- Appliances and fixtures (taps, toilets, washing machine, dishwasher, etc.) with quick-closing valves can cause water hammer. In the event that you have newly installed appliances or fixtures, check the pipes to see if they’re loose.
Mixer Taps vs. Traditional Taps: Does the Type Matter for Water Hammer?
Yes, the style of tap you have can make a big difference when it comes to water hammer. Traditional taps generally close gradually, allowing the water flow to slow down before stopping completely. This helps prevent sudden pressure changes in your pipes.
On the other hand, modern mixer taps are designed to be quick and convenient—they shut off almost instantly with a flick of the handle. This rapid shut-off can suddenly halt the flow of water, causing a pressure spike and a higher risk of water hammer, especially in homes with older plumbing systems.
So, if you’ve upgraded to mixer taps in an older house, keep an ear out for unexpected noises, as your plumbing may be more prone to water hammer. Consider checking that your pipes are properly secured or talk to a plumber about solutions like water hammer arrestors.
- Loose pipes can also cause water hammer, especially parts like the plumber’s tape, ring hangers, brackets, and other straps that are used to secure the pipes.
A Simple Fix for Noisy Pipes That Aren’t Water Hammer
Sometimes, those banging or knocking sounds in your pipes may not be true water hammer at all—they might just be caused by trapped air pockets. These air bubbles can mimic water hammer, causing similar clanging noises without the same risk of pipe damage.
Here’s an easy fix you can try:
- Start by turning on the tap closest to your water meter.
- Then, one by one, turn on the remaining taps throughout your home until every one is running.
- Once all taps are open and the water is flowing freely, turn them off in the reverse order.
This process helps flush out trapped air and can often quiet those pesky noises. If you’re lucky, the noise will disappear, and you won’t need to dig any deeper into your plumbing woes!
- Toilets are prone to water hammer because of the toilet fill valve. A faulty valve either closes too quickly or does not close completely at all, so it can cause sudden water stoppage inside your pipes. What you can do is to replace the entire stem to fix the problem.
Loud banging or clanging noises inside your plumbing fixtures can lead to bigger problems. The louder they are, the bigger the future problem will be. Don’t hesitate to call on professional plumbers when you are faced with water hammer issues.
Other Common Plumbing Problems and Simple Fixes
Noise and leaks aren’t exclusive to water hammer. Here are a few other plumbing headaches you might run into, along with what you can do about them:
- Noisy Taps: If your tap squeals or rattles every time you turn it on, the culprit might be a worn washer, loose parts, or sediment build-up. Replacing the washer or cleaning out the aerator often does the trick. Still banging? Time to check those pipes for air or loose fittings—similar culprits to water hammer.
- Leaky Taps: That persistent drip from your tap isn’t just annoying—it can waste buckets of water over time. Usually, a worn-out washer or O-ring is to blame. Replacing these smaller components is a simple DIY project with the right tools.
- Thermostatic vs. Tempering Valves: If you’ve ever wondered why your shower alternates between arctic and volcanic temperatures, it might come down to the valve. Thermostatic mixing valves keep water at a steady temperature by making fine adjustments, while tempering valves just mix hot and cold water to a set ratio. Knowing which one you have (and if it’s working properly) can save a lot of shower-time surprises.
No matter the issue—strange noises, constant drips, or unpredictable temperatures—catching and fixing these problems early will help keep your plumbing running smoothly.
