Water heater warning signs, and who to call about them

Why water heater warnings deserve attention

A water heater combines water, electricity or gas and heat in a small space, often in a bathroom with little ventilation. Most of the time it works quietly in the background, which makes it easy to miss the early signs that something is wrong.

This article lists the warning signs on storage and instant heaters, the safe first steps you can take, and how to decide whether the job needs an electrician, a plumber or a gas worker. It does not cover how to choose a new heater: the water heater guide and the instant water heater guide explain repair, replacement and what to compare.

Warning signs on any heater

Some signs apply to both storage and instant heaters.

• The breaker trips when the heater is on: this can point to a fault in the heater, its wiring or moisture getting into electrical parts.
• Water leaking from the unit or its pipes: look for drips from the body, the inlet and outlet pipes or the pressure relief valve.
• Rust or discolouration: rust stains on the casing or brown water from the hot tap only can mean corrosion inside.
• Scalding or very unstable temperature: water that turns suddenly very hot, or swings between hot and cold, can mean a faulty thermostat or control.
• A burning smell, scorch marks or a hot switch: stop using the heater straight away.
• Water coming into contact with the heater's switch or wiring: treat this as urgent.

Signs specific to storage heaters

Storage heaters keep a tank of hot water ready, so their warning signs often relate to the tank and its fittings.

• Knocking, rumbling or popping noises: often caused by sediment building up inside the tank as it heats.
• Constant dripping from the relief valve: the valve may be faulty, or the pressure or temperature inside the tank may be too high.
• Hot water running out faster than before: the element or thermostat may be failing.
• Bulging, dents or damp marks on the casing: signs that the tank itself may be damaged.

Signs specific to instant and gas heaters

Instant heaters heat water as it flows, so problems tend to show up while the shower is running.

• The heater trips or cuts out during use: this can be an electrical fault or a sign that water flow is too low for the heater to work correctly.
• No hot water even though the indicator light is on: often a failed element or flow sensor.
• Crackling or buzzing from the unit: switch it off and have it checked.

Gas water heaters need extra care. If you smell gas, do not switch any electrical device on or off, avoid any flame, open windows and doors, close the gas supply valve if it is safe to reach and leave the area. Contact your gas supplier's emergency line from outside the home. EMA's gas safety page has general advice on using gas safely at home.

Safe first steps

For an electric heater showing any of the warning signs above, a few steps will make the situation safe while you arrange a check.

• Switch off the heater at its isolator switch, then at the DB box if you are unsure the isolator is working.
• If water is leaking near the heater's switch or wiring, switch off the bathroom circuit or the main switch at the DB box before you go near it.
• Close the cold water supply valve to the heater to stop any leak.
• Do not reset a tripped breaker again and again. If it trips a second time, leave it off.
• Take photos of the heater, its label, any leak and the DB box for the person you call.

EMA's electrical safety page gives general guidance on staying safe with electricity at home. If your breaker trips often, the power trip guide explains what to check next.

Who to call: electrician, plumber or gas worker

Water heaters sit across several trades, and the right person depends on the problem.

• Electrician: for tripping, burning smells, scorch marks, faulty isolator switches or wiring to the heater.
• Plumber: for leaks from pipes, valves or the tank, low hot-water flow and replacing the heater itself. Many plumbing companies install heaters and work with an electrician for the electrical connection.
• Gas worker: for any gas heater fault, gas smell or work on gas pipes. Do not attempt any gas work yourself.

EMA's page on engaging licensed workers explains which electrical work needs a licensed worker and how to check one. For gas work, see EMA's page on the gas service worker licence. When you call, ask who will do each part of the job and whether they hold the relevant licence.

What water heater installation costs, from published rates

If the heater needs replacing, several companies publish installation rates. The table shows the lowest matching rate each company publishes, with its source and capture date. These are advertised rates with conditions, not quotes, and they may not include the heater itself or extra pipe and wiring work.

FROM THE HOMEZYPRO DIRECTORY

Published water heater installation rates

For the most common unit (per job), the lowest published rates from 5 companies run from S$120 to S$288. Each figure is one company's own advertised rate with its conditions, not a market average or a quote.

See 5 published water heater rates and sources

Lowest matching advertised rate per company, in SGD as published. "From" marks a starting price and ranges are shown in full. Check the source for minimums, GST and inclusions.

Company	Service as listed	Rate	Source
BS Integrated Engineering Pte. Ltd.	13A water heater point	S$120 per job	247plumbingandelectrical.com
SHS Engineering Pte. Ltd.	Water Heater Installation	From S$120 per job	shshandymansg.com
NILE Plumbing	Install Instant Water Heater	From S$160 per job	nileplumbingsg.com
PW Plumbing Services	Water Heater Installation	S$200 to S$500 per job	pwplumbing.com.sg
Reliable Plumbing Services - U-Home Plumbing & Engineering	707 Protek Instant Water Heater with Hand Shower Set	S$288 per job	u-homehardware.com

Questions

Is it safe to keep using a water heater that trips the breaker?

No. Switch the heater off at its isolator and leave the breaker off if it trips again. Have an electrician check the heater and its wiring before you use it.

Should I call a plumber or an electrician for a leaking water heater?

Start with a plumber for leaks from the tank, pipes or valves. If water has reached the heater's switch or wiring, switch off the power and have an electrician check the electrical side as well.

What should I do if I smell gas near a gas water heater?

Do not switch electrical devices on or off, avoid any flame, open windows, close the gas valve if it is safe to reach and leave the area. Call your gas supplier's emergency line from outside.