5 Most Common Water Heater Problems (And How to Fix Them)

A water heater is an essential home appliance that provides hot water for showers, washing dishes, and doing laundry. However, like any other household equipment, it can develop problems over time. In this article, we will walk you through the 5 most common water heater problems, how to fix them, and when to call a professional water heater repair service.

Whether you're dealing with inconsistent temperatures or a noisy unit, knowing what’s wrong can save you time, money, and stress.

1. No Hot Water

Possible Causes:

Faulty thermostat

Broken heating element

Tripped circuit breaker

Gas supply issues (for gas heaters)

What You Can Do:

Electric Heater:

Start by checking your home’s circuit breaker panel. If the water heater’s breaker has tripped, reset it and wait to see if the unit begins heating again. If it trips repeatedly, do not attempt to reset it multiple times this may be a sign of a serious electrical fault that requires immediate professional attention.

Inspect the thermostat settings on the heater. Ensure they are set to your desired temperature ideally between 49°C to 60°C.

If you feel comfortable and have the appropriate tools, test the thermostat or heating element using a multimeter. These parts may wear out over time and often need replacing after a few years of use.

Gas Heater:

Confirm that your gas supply valve is fully open. Sometimes the issue may be as simple as an accidentally closed valve.

If your unit has a pilot light, ensure it hasn’t gone out. You can follow the manufacturer’s instructions to relight it. Be cautious, though if you smell gas, do not attempt to relight anything. Leave the property immediately and contact your gas provider or emergency services.

Modern gas heaters often have electric igniters. If this component fails, the gas won't ignite, and the unit won’t heat water.

If the issue persists despite these steps, it’s a sign that professional help is necessary. Faulty internal wiring or a malfunctioning control board may require diagnosis and repair by a licensed technician. To avoid safety risks and further complications, it’s best to contact a reputable water heater repair service like HDB Plumber Service. Their team of experienced plumbers can quickly identify the root cause and restore hot water to your home safely and efficiently.

2. Inconsistent Water Temperature

Possible Causes:

Malfunctioning thermostat

Sediment build-up inside the tank

Aging heating elements

What You Can Do:

Flush the tank to remove sediment build-up. Over time, minerals can settle at the bottom of the tank, reducing heating efficiency and causing temperature fluctuations. Draining the tank helps improve performance and extends the lifespan of your unit.

Adjust the thermostat settings to your desired temperature. Ensure it is set between 49°C and 60°C for optimal comfort and safety. Too low, and the water may feel lukewarm; too high, and there’s a risk of scalding.

Inspect the heating element for any signs of rust, corrosion, or wear. If damaged, it should be replaced promptly to maintain consistent water temperature.

3. Water Leaks

Possible Causes:

Loose valves or pipe connections

Cracked tank

Worn-out gaskets or seals

What You Can Do:

Tighten any loose connections. Begin by checking all visible pipes, joints, and fittings around the water heater. Use a wrench to gently tighten any loose components, but avoid overtightening as this may cause damage. Even a small looseness in pipe fittings can lead to persistent leaks if not corrected promptly.

Inspect the pressure relief valve and replace it if leaking. The pressure relief valve is a safety mechanism designed to release excess pressure inside the tank. If you notice water dripping from this valve, it may be a sign that the valve is faulty or the system pressure is too high. Shut off the water supply before attempting any replacement, and refer to the manufacturer’s guide or seek help from a qualified plumber.

Use a bucket to catch dripping water and reduce damage until repairs are done. If the leak is ongoing and cannot be fixed immediately, place a bucket or waterproof container beneath the leak to prevent water from damaging floors or walls. In addition, consider placing an old towel or absorbent cloth around the area to catch any splashes.

If the leaking continues or worsens despite these measures, it's best to shut off the water heater and call a professional. Leaks can signal internal tank corrosion or more serious faults that DIY methods cannot resolve. Acting quickly will help prevent further damage and ensure your system remains safe and functional.

4. Strange Noises From the Heater

Possible Causes:

Mineral deposits inside the tank

Heating element burning out

Expansion and contraction of metal parts

What You Can Do:

Flush the tank to remove mineral build-up. Over time, minerals like calcium and magnesium from hard water can settle at the bottom of the tank, creating a thick layer of sediment. This sediment not only reduces the heater’s efficiency but can also cause overheating and noisy operation. Flushing the tank every six to twelve months can help prevent this issue. To flush the tank, turn off the power supply, attach a hose to the drain valve, and direct the water to a safe drainage area. Open the valve and allow the tank to empty completely before refilling and restarting the heater.

Listen carefully to identify the type of noise. Different sounds often indicate different problems. For example:

Popping or rumbling sounds usually result from steam bubbles trying to escape from beneath sediment.

Whining noises may indicate scale build-up on electric heating elements.

Banging or knocking sounds could suggest rapid water expansion or sudden shifts in pressure.

By pinpointing the type of sound, you can better determine what maintenance or repair is required. If flushing the tank does not eliminate the noises, it might be necessary to inspect or replace heating elements or consider adding a water softener system to minimise future scale accumulation.

Persistent or loud noises should not be ignored. If you feel uncertain about conducting these steps yourself, it’s best to contact a professional water heater repair service to safely assess and resolve the issue.

5. Discoloured or Smelly Water

Possible Causes:

Rust inside the tank or pipes

Bacteria buildup

Corroded anode rod

What You Can Do:

Run the hot water tap for a few minutes to see if the issue clears. Sometimes, water may appear discoloured or have a slight odour due to temporary build-up in the pipes, especially if the heater hasn’t been used for a while. Allowing the system to run for a few minutes can help flush out stagnant water and improve clarity.

Flush the tank to remove any bacteria or rust. Over time, sediment and rust particles can accumulate at the bottom of the tank, creating the perfect environment for bacteria to thrive. These particles can affect both the colour and smell of your water. Regular flushing helps eliminate these contaminants, keeping the water fresh and clean. It’s advisable to flush the system every 6 to 12 months to maintain hygiene and performance.

Replace the anode rod if it’s corroded. The anode rod plays a crucial role in preventing rust by attracting corrosive minerals in the water. Once the rod is fully corroded, these minerals start attacking the tank itself, leading to rust-coloured water and potential tank failure. If your water continues to appear reddish or brown even after flushing, the anode rod may be to blame. Replacing it can significantly improve water quality and extend the life of your heater. This task is relatively straightforward for experienced DIYers but is best performed by a qualified plumber to ensure proper installation and safety.

By carrying out these steps, you can often restore the water’s appearance and smell. However, if the problem persists despite your efforts, it may indicate a deeper issue inside the tank or the plumbing system.

Additional Common Issues to Watch Out For

6. Low Hot Water Pressure

Possible Causes:

Sediment or mineral build-up in the pipes

Partially closed shut-off valves

Corroded plumbing

What You Can Do:

Check and fully open shut-off valves. Sometimes, the valves controlling water flow may not be completely open, which can restrict pressure. Make sure the cold water inlet and hot water outlet valves on the heater are turned all the way on.

Clean out faucet aerators and showerheads. Mineral deposits from hard water can accumulate inside faucet aerators and showerheads, narrowing the opening and limiting water flow. Remove these fixtures and soak them in vinegar for a few hours to dissolve build-up. Use a small brush or toothpick to clean out any remaining debris before reattaching.

Additionally, consider checking pipes connected to the water heater for blockages. If your home has older galvanised steel pipes, internal corrosion may be reducing flow. Installing newer PEX or copper pipes may be a long-term solution.

Regular maintenance of your entire plumbing system will help preserve water pressure and heater efficiency. Monitoring changes in pressure and addressing small problems early can prevent bigger issues later.

7. Water Taking Too Long to Reheat

Possible Causes:

Undersized water heater for household needs

Ageing or damaged heating elements

What You Can Do:

Reduce water usage during peak times.

Schedule an inspection to evaluate heater capacity.

Using your water heater wisely during busy hours like mornings and evenings can help reduce the load on your system and improve its lifespan. If your family uses a lot of hot water at once, your current unit might not be large enough to keep up. A professional inspection can determine whether your heater is meeting your household’s needs or if it’s time for an upgrade. Installing a more energy-efficient or larger-capacity heater may improve performance and cut energy bills. Keeping up with regular servicing also helps ensure your system runs efficiently year-round.

How to Prevent Water Heater Problems

Regular maintenance can help you avoid many of these common issues. Here’s what you can do:

Flush the tank every 6–12 months

Check and replace the anode rod every 2–3 years

Inspect valves and seals regularly

Schedule annual inspections with a licensed plumber

Need professional help? Visit HDB Plumber Service for expert water heater maintenance and repair in Singapore.

When Should You Replace Your Water Heater?

If your water heater is more than 8–12 years old, repairs may become more frequent and costly. Consider replacing the unit if you experience:

Constant leaks

No hot water

Skyrocketing energy bills

Visible rust or corrosion

Speak with a licensed technician to evaluate your unit and recommend the right course of action.

Choosing the Right Water Heater for Your Home

When replacing your old unit, choosing the right water heater can improve energy efficiency and comfort.

Types of Water Heaters:

Storage Water Heaters: Store and heat water in a tank. Ideal for larger households.

Instant Water Heaters: Heat water on demand. Space-saving and energy-efficient.

Considerations:

Size of your household

Frequency of hot water usage

Energy efficiency ratings

Installation costs

Why Choose a Professional Water Heater Repair Service?

DIY repairs can be risky, especially for gas or electric water heaters. Certified professionals offer:

Accurate diagnostics

Safety and compliance with regulations

Long-term cost savings

Access to proper tools and replacement parts

Choosing a reputable water heater repair service in Singapore like HDB Plumber Service gives you peace of mind and reliable results.

FAQs

1. How often should I flush my water heater?

It’s recommended to flush your water heater every 6 to 12 months to remove sediment and prevent damage.

2. Is it safe to repair a water heater by myself?

You can do basic troubleshooting, but for electrical or gas-related problems, it’s safer to hire a professional water heater repair service.

3. How long does a water heater usually last?

With regular maintenance, a water heater can last between 8 to 12 years.

Conclusion

Your water heater is a crucial part of your daily routine. When issues arise, knowing the cause and solution can make a big difference. For persistent or complex issues, don’t hesitate to contact a professional water heater repair service.

A trusted company like HDB Plumber Service ensures your water heater runs efficiently, saving you time and avoiding expensive breakdowns.