4 Reasons Why Your Cold Water Tap Makes A Loud Noise

Does your tap make a loud noise every time you turn it off? Here is how to troubleshoot and fix that faucet.

It can be alarming to hear a loud bang or knocking sound when you turn off your cold water tap. The most common reasons for a noisy tap is water hammering, high water pressure, and valves that are either faulty, filled with mineral deposits - or both.

It is important to understand why these hiccups happen before trying to fix them. Here are all the reasons and remedies you need.

The Reasons Your Cold Water Tap Turns Noisy

Did this happen to you? After washing your hands or filling a glass of water, you turn off the cold water tap - only to be bombed by a loud bang. Besides frightening some people (hey, admit it), hearing such noises can be a cause for concern. How serious is it? Can you diagnose and fix the problem yourself? But firstly, let’s look at why your cold tap gets cranky when you turn it off.

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Water Hammering

Loud bangs are often caused by something that is aptly called “water hammering.” Indeed, it sounds like there is an evil elf inside your pipes giving them a good whack with his hammer. A common misconception is that all or most loud bangs in plumbing pipes are water hammer events. But that is not entirely correct.

True water hammering is caused by an abrupt stop in water flow. Plumbers call this “hydraulic shock.” The banging noise happens when the water is suddenly forced to change direction. In this case, the water is blocked suddenly when you shut off the tap.

How Do I Fix Water Hammering?

Once you have established that water hammering is behind that loud bang, there is something that you can do before calling the plumber guy. Two things, in fact.

Is the knocking sound relatively muted and you could not find leaks anywhere? Try this.

1. Wrap cushioning material around the pipes. The padding steadies the affected pipes and also prevents them from rattling or colliding with a nearby surface when the water flow is strong.
2. You can also tighten all the pipe fittings to reduce vibrations. Here are more tips on how to tighten pipe fittings.

Unfortunately, water hammer can do far worse than just shake a pipe. With more intense events - think loud noises and leaks - the only solution might be to get professional help. A plumber can tweak the plumbing system by adding extras such as air chambers or devices that are designed to specifically deal with water hammer.

Problems With The Shut-Off Valve

When the valve is no longer working properly, it can cause sounds when you use the cold water tap. The most common mishaps with shut-off valves are wear and tear over the years and scale build-up. Both issues are more common in areas with hard water.

How Do I Fix Faulty Valves That Are Noisy?

When the shut-off valve is the culprit, you need to determine whether wear and tear or scale is the problem. It is pretty easy to see normal damage - the valve just looks bad. Limescale is a grey-white mineral deposit. If limescale is bad, you will see it on the outside of the pipes but most of the time, the deposits are hidden inside.

You can fix a scale-ridden valve at home. Take some white vinegar and water. Mix equal parts - half a cup of each should do it. Dunk a cloth in the mixture and soak it well. Wrap the cloth around the shut-off valve, leave for a couple of hours and then rinse with clean water.

If the vinegar water failed to clean the valve, the bangs continue, or the valve is damaged from wear and tear, then you need to replace it. If you have a good handle on dealing with plumbing yourself, this should be easy. Otherwise, do not hesitate to call a reputable plumber to sort out your tooting tap.

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High Water Pressure

Is high water pressure behind the noise? There is one way to be sure. The bangs and knocks are more common when the cold water tap is open and running. Higher pressure makes water move at a rapid clip, enough to rattle pipes and make them produce some alarming sounds. Including loud bangs.

This could be one of the harder issues to fix. But it is not impossible. As we mentioned a little earlier, you are likely dealing with high water pressure when the bangs and rattles happen when you open the cold water tap. The first step to reducing water pressure in your plumbing is to discover how high or low the pressure actually is.

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A surefire way to determine water pressure is to purchase a test gauge. These devices are designed specifically to test the pressure at a specific location (like that offending cold water tap).

Here’s how they work.

1. The test gauge is attached to an open valve. In this case, it would be the one in your cold water tap.
2. The person who is testing the water pressure then turns on the cold water tap.
3. A reading shows up on the gauge, accurately depicting the pressure of the water flow.

What Is A Normal Reading?

In plumbing language (it’s a thing), PSI is the unit that measures water pressure. It stands for “pounds per square inch.” Experts seem to differ on what a normal reading might be for residential plumbing. Some say it must fall between 30 and 80 PSI while others consider it more narrowly - 40 to 45 PSI or 60 to 80 PSI. You can always contact your local municipality or council to find out what the desired reading should be in your area. A local plumbing company can also tell you.

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My Water Pressure Is Too High. How Do I Fix It?

Shoot. You did the reading and consulted the local experts. The water pressure in your tap is too high. The problem is serious. Yes, it makes your cold water tap noisy. But high water pressure in your plumbing system can be disastrous in the long run. It causes tiny leaks everywhere, spikes your municipal bill, and damage appliances that use water.

What is the next step after discover high water pressure?

1. Purchase a valve called a water pressure regulator. If you already have one, then it’s not working. It needs to be replaced.
2. You now need to adjust the valve to correct the pressure.
3. Shut off the main water supply.
4. The water pressure regulator has a locking nut or device. Loosen it so that you can adjust the pressure.
5. Turn the screw to the left to decrease pressure and to the right to increase pressure. Only adjust the pressure a small amount each time (a quarter of a turn should be enough).
6. Test the system and adjust the regulator until the gauge gives you the right PSI.
7. Fasten the locking nut on the regulator.
8. Gently turn the main water supply back on.

A Quick Summary On Noisy Cold Taps

• Loud noises from a cold tap are caused by water hammer, faulty valves, or high water pressure.
• Some issues are slight (rattling pipes) while others can damage your plumbing system (high water pressure).
• Someone with DIY experience can fix most of these issues but for the more serious cases, it’s best to call a plumber.