Vibrating Hot Water Heater Pipes | DIY fixes

A neighbor complained recently about being woken up in the dead of the night by loud banging sounds coming from his ensuite bathroom where his wife was trying to take a shower. Someone at a party a while ago had a funny story about how her dog went nuts, growling and barking at the strange pings and cracking noises coming from her hot water plumbing. Having heard many stories like these about weird noises coming from the hot water systems inside houses, I thought I’d finally sit down to write a post about it.

This article covers the most common causes of vibrating hot water heater pipes in the shower as well as the rest of the hot water plumbing. But here at HVAC-Buzz, we don’t like to just leave you with an understanding of your problems, so there are also some excellent fixes to try. So, plunge in!

Sounds in the Shower: Common Causes and What to Do About Them

Clogged Showerhead

Right, so one of the most common reasons for weird noises when you’re trying to shower is that there’s a pressure build-up inside the hot water system as a result of an obstruction in water flow.

If your bathroom fittings are more than a few years old, and especially if you live where there is a hard water supply, the chances are that the holes in your showerhead are clogged with lime-scale build-up. Another possibility is that recent maintenance or construction work might have caused grit to accumulate behind the showerhead.

Solution

The good news is this is an easy problem to resolve. Before you do anything with your house’s plumbing system, make sure to turn the water supply off at the mains.

Just unscrew the showerhead, and soak it in a solution of equal parts water and vinegar. Leave it for two to three hours, then use a toothbrush or other soft-bristled brush to gently scrub the remaining scale off the outer and inner surfaces of the showerhead.

This should get your showerhead working as good as new, and banish those banging noises!

Alternatively, simply switch out the showerhead for a new unit. In some scenarios, the scale accumulating behind showerheads and faucet aerators might be due to rust in the iron pipes. In such cases, your sole recourse is to replace the entire section of rusty iron piping.

Tip: You could use a similar treatment to de-scale the faucet aerators in your house, including those for the bathtub, washbasin, and kitchen sink. For more on how to do this, take a look at Troubleshooting Aerators with Water Heaters (DIY pics).

Water Hammer

Now, you may already be familiar with the term “water hammer”, properly termed hydraulic shock. This phenomenon is caused by water “slamming” against any obstruction in the plumbing, such as a faucet or valve that is suddenly shut off, or even against a valve that will not open fully to allow water to flow.

Often, folks will begin to note water hammer problems as their plumbing fixtures wear out over time. With continued use, the rubber or neoprene washers or ceramic discs inside faucets and shower mixers become damaged, with nicks, chips, and cracks. Rubber washers, especially, tend to grow brittle and “curl up” over time.

As these parts begin malfunctioning, they cause valves not to close or open fully. Because of this, water at high pressure might flow back and forth within the system, creating turbulence and shock waves that vibrate through the plumbing with loud rattling, banging noises.

Solutions

Here’s a list of fixes for the water hammer problem in the plumbing behind your shower, going from cheapest to most expensive.

1. Replace Rubber or Neoprene Washers in Shower Cartridge Valve

Since the designs of shower mixers (and faucets) vary considerably across makes and models, it’s best to find a YouTube video that shows how to replace these parts. See, for example, this video showing how to replace the rubber washers on a single faucet shower.

2. Replace Shower Cartridge Valve

Again, find a video that shows you how to do this for the make and model you have in your shower. See this video for an example of how to do this with a single faucet shower.

3. Replace Pressure Balancing Spool in Shower Mixer Assembly

Keep in mind, older shower mixers don’t come with pressure balancing spools. You can only try this fix (see video) if you’re sure that yours has one, and you suspect that a worn-out or clogged-up spring inside the pressure balancing spool could be the problem.

Tip: A properly functioning pressure balancing spool makes a rattling noise when shaken vigorously, whereas one that’s clogged with scale or grit inside won’t rattle.

4. Replace Ceramic Disc Valve

Tip: If you’re just not sure what kind of shower cartridge valve you have in your shower, watch this explainer video to figure out which one of the four types matches yours.

From dealing with noises coming from the hot water pipes in your shower, we’ll move on to look at how to deal with an overall noisy hot water plumbing system.

DIY Fixes for Noises Affecting All Hot Water Plumbing

Often, bizarre noises in the hot water pipes are not limited to the shower but may occur all over the house. How can you locate the source of the noise in such cases, and what can you do about it?

Temperature Changes Affecting Plastic Piping

If your home has plastic plumbing, the chances are high that you’ll encounter loud ticking and clicking noises that could creep you out, especially since these noises often occur at steady intervals.

Don’t worry, this is just the plastic of the pipes expanding or contracting as it reacts to the water flowing through it: hot water will obviously cause the plastic to expand, while cold water will cause it to contract back again.

Solution

Here again, there are a couple of fairly simple fixes:

• If your home needs can be met with water that is less hot, go ahead and reduce the temperature setting of the water heater. For example, set it at 110 °F instead of 140 °F. This could help reduce the ticking noises in your hot water pipes.
• Alternatively, you could wrap foam insulation around exposed sections of your hot water pipes. This will reduce the extent to which they contract back once hot water has been drawn at the faucet. Plus, it’ll act as a muffler, so you won’t hear the noises as much.

More Water Hammer

As explained in the first section, when water “slams” into obstructions in the plumbing, it sets up violent shock waves that can cause plumbing to vibrate. It’s important to realize that although this might not seem like a serious problem, it causes increased wear and tear on the plumbing—pipes, joints, valves, and faucets, and could lead to expensive repairs. It is therefore important to address water hammer issues early before they cause much damage.

There are a few major suspects when it comes to water hammer in the hot water plumbing:

1. Busted or Absent Water Heater Expansion Tank

Noise in hot water pipes during cold weather often arises from water hammer caused by dense, cold water expanding greatly as it heats up and seeks room in the plumbing system. This problem is absent in warm weather since inlet water temperatures are higher.

If you already have an expansion tank on your water heater, check to see if it is busted. Either replacing a malfunctioning expansion tank or installing a new one can solve this problem.

2. High Inlet Water Pressure

Civic authorities across the United States require that residential water supply pressure should be regulated between 30 and 80 psi. In many areas, this is ensured by installing either a check valve or a pressure reducing valve (PRV) at the main cold water inlet to a house.

If for some reason, this valve has not been installed in your home, or if the valve is malfunctioning, it could cause excessive pressure (greater than 80 psi) in the water flowing through your pipes, leading to vibrating, noisy pipes.

3. Malfunctioning Ballcock Valve in Toilet

Clanging or humming noises in domestic plumbing may arise from a malfunctioning ballcock valve assembly, a worn-out valve washer, or even a disconnected overflow tube in one of the toilets. This is sufficient to set up a water hammer effect, as water flows back into the pipes from the toilet cistern.

Keep in mind that the ballcock valve is not the location of the strange noises. Rather, it’s the ‘harmonics’, or the frequency of the vibrating water pipes that creates the clangs, rattles, or humming noises throughout the household plumbing.

Solutions

The solution you implement in your home will depend on the exact causes of water hammer in your hot water plumbing:

1. Replace or Install New Expansion Tank

As described above, this is the most appropriate solution if your hot water plumbing makes loud rattling, clanging noises only during the cold weather (fall and winter), but grows quiet again in the warmer months.

You also have the option of installing a Thermal Expansion Relief Valve, or TERV down-line of your water heater. To decide whether an expansion tank or a TERV is better suited to your needs, see Water Heater Thermal Expansion: Relief Valves or Expansion Tanks?

2. Replace or Install Check Valve or PRV

This could be the ideal solution if the main inlet to your house is carrying water at excessively high pressures (greater than 80 psi). In this case, however, you need to have a licensed professional install the valve, in order to meet code requirements.

3. Replace Ballcock Valve Washer or Ballcock Valve Assembly

This straightforward DIY job will take you less than 20 minutes in all if done right. For how to do this, watch this helpful video.

4. Install Water Hammer Arrestors in the Domestic Plumbing

A water hammer arrestor (in case this term is new to you) is a device that acts as a shock absorber. Like an expansion tank, a water hammer arrestor has a rubber bladder inside that vibrates, safely and quietly absorbing the turbulent energy of the water hammer.

Again, water hammer installation is not an average, straightforward DIY project, but requires the services of a licensed, professional plumber. First, s/he will assess the plumbing system across the entire house, in order to identify the appropriate locations where such a device is needed, before going ahead with the installation.

And that’s it, y’all. Now you’re aware of nearly every reason behind those mysterious creaks, rattles, and bangs in your home’s hot water plumbing. What’s even better, you have a fix for each one of ’em… so go to it!