How to Fix Water Hammer in Shower

If you hear a thumping sound or a loud bang when you turn your shower tap off, run the dishwasher or washing machine, most possibly you have a water hammer issue in your home. While you might think that water hammer is a simple harmless everyday sound from your plumbing system, it can gradually damage your plumbing system thereby costing you’re a fortune in repairs and most probably replacements.

Therefore, learning a few basics and knowing how to fix water hammer in shower, can see you save thousands of dollars in repairs and replacement in future.

How Do I Know I Have Water Hammer Problem?

Water hammer, also referred to as hydraulic shock is both a sound and a sensation. So, when you suddenly shut off your faucet or shower tap, you may hear a loud noise up in your piping system. Since the sound is vibration, the water hammer effect is often strong enough to feel it under your hand as you hold the shower tap of the faucet.

You may also see the faucet slightly shake in vibration. In fact, the shock generated by water hammer can cause your bathroom sink and adjacent bathroom cabinets to vibrate. You may also hear the hydraulic shock sound reverberate within your house’s interior structure.

What Causes Water Hammer

Water hammer occurs because water is shut off swiftly. Although bathtub, shower faucets and sink can cause water hammer, often dishwashers, and cloth washers cause water hammer since they can close water faster quickly than the human hand. This is because these appliances use solenoid valves that can shut off the water in just 30 milliseconds.

The sudden stoppage of water flow in the plumbing system causes water to bang against beams, studs, joists or even against other drain and water supply pipes. Other common factors that cause water hammer include:

Waterlogged air chambers

Usually, water pipes are built with air chambers that act as cushions to absorb the shock waves created by water when it comes to a sudden stop. However, when these air chambers are waterlogged, they can provide any cushion to prevent the shock waves created from colliding with the inside of the pipes. As a result, a loud sound is created and substantial damage to the plumbing system.

Vacuum Created by Closing of the Valves

A vacuum can be created, especially when an upstream shower faucet in the pipe connections while the water downstream continues to flow. The created vacuum can cause the pipe to collapse or implode more so if it is a downhill pipe, thus generating a water hammer effect.

Loosely Attached Pipe-Mounting Straps

When your plumbing system is not properly secured, it may be possible to hear water hammer effects, especially when the sound vibration or the shock waves are stronger. When the water hammer effect is stronger, it can cause the pipes to jostle against the framing and other structures in your walls, ceiling or floor where the plumbing system passes.

Worn-Out Stop Valves

Water hammering can also be caused by worn out stop valves. Worn stop valves cause a water hammering effect because they have loose gland packing and or worn-out washers. With this condition, the valves will open when the water hammer shock wave passes through the pipes to rattle the loose valve handle and generally loose jumper.

Water Kitchen and Bathroom Appliances

If the banging sound started after you installed new appliances in your home such as washing machines and dishwashers, then the likely problem is with the solenoid valves. These appliances come with a water supply system that is controlled by solenoid valves that are electronically operated thus stopping water flow instantly. As a result, the water reflects back up the pipes while creating a shock wave, in turn, causing a water hammer.

How Do I Get Rid of Water Hammer?

Your water hammer problem can be easy or complex to fix, depending on the cause. Regardless, most causes of water hammers in the shower can be handled by a home handyperson with basic plumbing knowledge and tools. So, you want your water hammer problem fixed? Here are some of the ways of how to fix a water hammer in shower.

1.   Reduce Water Pressure in your Plumbing System

High water pressure can be responsible for water hammer effects in your shower. Most building codes recommend residential pressure to be less than 80 PSI and higher than this can result in noise, leaks at joints as well as pinhole leaks in the pipes. The recommended pressure is between 40 and 60 PSI for the residential plumbing system.

If you are experiencing the water hammer effect at the faucet or appliance, be sure to check the pressure at that outlet with a water pressure gauge. If you measure and find that the water pressure is more than 60 PSI, consider reducing the excessive pressure to the fall between the recommended water pressure for the home’s plumbing systems.

To reduce your water pressure, find the pressure regulator that is often located between the main shut-off valve and the water meter. The pressure regulator may also have a pressure gauge that you can check as well. If the pressure regulator doesn’t have a pressure gauge, you might require to call a plumber to install it, especially if you have a water meter on the line. Most importantly, the plumber can also adjust your water pressure to the recommended range.

If you checked your water pressure and adjusted it accordingly at the faucet, you can remove the pressure gauge. Reattach the aerator and run the water. Close the tap off faster and if your water hammer problem was occasioned by high water pressure, then it should be fixed by now. If you still hear the loud sound as a result of the water hammer, then attempt a different solution.

2.   Fix Waterlogged Air Chambers

If you live in a home that was built before the 1960s, the plumbing system probably has the air chambers located on the hot and cold water lines after each tap. These air chambers are often installed on-site by adding an upside-down “T” joint on the pipe. The capped length of the line, at least 12 to 18 inches in length while having the same diameter as the water pipes are inserted into the upward joint.

When this plumbing system is charged with water, the leg of the “T” would ‘pressurize’ with trapped air. Water hammer is caused by the water being unable to expand because water is not compressible. Regardless the air trapped in the capped part of the ‘T’ near the faucet is highly compressible, thus allowing the water to expand in the space thereby eradicating the water hammer.

However, with time these air chambers can get filled with water to cause water hammer bang. If you have just started to hear a bang, then this could be the most likely cause. The remedy is to drain the water to empty the air chamber as well as the water. When the plumbing system is filled with again, the chamber will equally be filled with air and therefore the water hammer should not occur again.

To efficiently drain the air chamber, shut off the water at the valve right at the feed line to the area where the water hammer effects are heard. Some valves come with a drain port at the bottom or side for the convenience of draining the water as well. With both the water and air drained out, the chamber will refill again. Proceed to turn off the faucet and open the shut valve you closed to recharge the pipes with water again. With the air chamber filled with air, the water hammer should not reoccur.

3.   Install Water Hammer Arrestors

A water hammer can cause the pipes and plumbing joints to leak as well as damage faucets and appliances because the generates high pressure. By installing water hammer arresters at the faucet, toilet or appliance where the noise is produced, you can mitigate the hydraulic shock damage. However, if a loud bang is heard from several locations in your plumbing system, be sure to install a hammer arrester at each location.

A water hammer arrestor work in a similar way as the air chamber but of course with some modifications. It features a manufactured air chamber with a diaphragm or piston in a sealed chamber and thread that fits into a tap.

So, when you shut the valve quickly, the water hammer energy expands into the arrestor where it is absorbed and silenced. To install your water hammer arrester, identify the location where the hammer effect is and pick a water hammer arrester that matches the flex pipe that links the noisy fixture.

Flush your shower to depressurize the location of the water pipe while removing as much water as possible before you connect the arrester. Using the channel lock plier or a wrench, loosen the coupling nearest the fixture. However, you should loosen the flex-pipe coupling for the fixture to be removed.

Wrap plumber tape around the metal thread of the hammer arrester as well as on the fixture connection. However, if all the fixtures are plastic, you don’t need to tape them. Thread the arrester to the fixture connection and tighten. Be sure that the fixture is correctly aligned as before.

Ensure the arrester’s air chamber is in the appropriate direction before tightening. Turn the water valve on to remove any trapped air. Make sure there are no leaks from the arrester and other fixtures you just connected. Open your shower faucet on and off severally. The water hammer should be gone!

4.   Replace Faulty Shower Cartridge

A shower cartridge works to divert water from the bath spout to the showerhead. However, when worn or is faulty, the cartridge may drip, let water leak out of the showerhead and spout, or close with the bang effect of the water hammer.

To replace your fault shower cartridge, turn off the main water valve for the shower. Open the faucet to depressurize and drain the remaining water. Cover the shower drain and other fixtures before your start the replacement.

Remove the tap handle carefully to prevent stripping the fasteners. Remover the cover plate or ring that is usually used to cover the cartridge. Ideally, cut the caulking seal to reach the fault cartridge that is held in place with a nut. Once you remove the bad cartridge it is time to install the new cartridge.

Lubricate the new shower cartridge for easier insertion. Wrap the fixture threads with the plumber’s tape before threading the nut into place. Tighten before covering. Turn the water supply on and check for any leaks. when you close the faucet, the loud banging should be gone.

5.   Secure Loose Pipes

If you have any loose pipes that are turning mild shock waves into loud and noisy bangs, you can mitigate this by securing these pipes with loose straps. Ideally, add new pipe straps or tighten the studs or joists.

6.   Cushion Water Pipes with Pipe Insulation

Pipes that are helped loosely by cross braces or pass in the walls may bang or rattle when water runs through them. Therefore, wrapping these pipes with pipe foam can stop the rattling or banging. Where the pipe has gone through the wall, be sure to fill the hole which they pass through with foam so as to prevent the pipe movement whenever you open your faucet to shower.

Conclusion

Water hammers can be annoying and damaging to your plumbing system. Knowing how to mitigate water hammers in the shower can go a long way to ensuring that you have a good showering experience while keeping plumbing system repair costs manageable. If you can’t reduce the water hammer because it is complex, call a professional plumber to fix it.

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