Ever heard loud sounds coming from your water heater?
Check out the sample sound clips below:
Recording of intermittent beeping
Recording of continuous whistling
You may hear a whistling noise or a high-pitched beep.
This comes and goes, and can happen even when the heater is off. The sound is from the relief valve, a safety part installed in all storage heaters.
What is a relief valve?
A relief valve helps release water from the tank to stop pressure from building up. This protects the tank from bursting.
The valve lets out pressure by dripping clean water. To keep the drips out of the way, a tube is sometimes attached to direct the water to a drain.
At all times, the valve must not be blocked.
What causes this sound?
1. Faulty relief valve. The valve can no longer hold the water pressure properly. It might even leak a lot of water, like a small tap.
Solution: To fix this, replace the faulty relief valve. It's a simple fix.
What is relief valve? Check #4 of This Article to find out!
2. The incoming water pressure is too high.
The valve controls pressure from both the heater and the water pipes. In most Singapore homes, water pressure is about 2.0 to 2.5 bars. If it goes above 3 bars (which is rare), the valve may start making noise.
Solution: Lower the water pressure
Contact your town council or building management to adjust the incoming water pressure. High pressure can damage your other water appliances over time.
Hearing Loud Sounds only at Certain Times?
If your relief valve makes loud noises only at specific times of the day, it could be due to unusually high water pressure.
Some people hear sounds late at night or in the afternoon, like at midnight or 3pm. This is because water pressure in your home isn’t constant, especially in HDB flats or apartments.
During off-peak hours, like midnight, fewer people are using water. This means pressure in the pipes can go up. While most households use water heavily around 7–9am and 7–9pm, pressure tends to be lower then.
So a good question to ask yourself is: When is the loud sound happening?
Knowing the timing can help you trace the cause more easily.
How does PUB control our water pressure?
We can't control water pressure on our own. Instead, PUB controls our water pressure for us with a low-pressure system.
This helps to lower water flow, reduce leaks, and make plumbing fixtures last longer. They do this by installing water tanks and pressure-reducing valves at different points in our estate.
This is a drawing of a PUB pressure reducing valve:
Source: PUB, Best Practice Guide for Water Efficiency
If you hear sounds from your heater…
Contact your warranty provider or a professional for advice. Like all parts, the safety relief valve can fail. Fix the problem early before it becomes a safety risk!
Loud Sounds FAQ
Can I still use my water heater if it’s making loud noises?
It’s not a good idea. A loud noise from your heater is a warning sign that something isn’t working right. Continuing to use it could lead to bigger problems or even safety risks. It’s best to stop using the heater and get it checked by a professional.
How often should I check my water heater’s relief valve?
You should check your heater’s relief valve at least once a year. If you start hearing loud or unusual sounds, it’s a sign to check it even sooner. Regular checks help catch small issues before they turn into expensive repairs.
What other signs (besides loud sounds) show that my water heater needs servicing?
Apart from loud noises, watch out for leaking water, rusty water from the taps, strange smells, or inconsistent water temperature. These are all signs your water heater needs servicing. Never ignore loud sounds or other warning signs. Fixing them early can save you money and keep your home safe.
