Clues from Central Coast Council's water notes
Rotten egg smell from the hot tap only
Council says that points to a possible problem with the hot water system. If the smell is strong from both hot and cold taps when they're first turned on, contact Council instead.
Blue stains in basins or the shower
Council says these are common where the hot water cylinder is copper.
Rusty or black water after a few minutes
Corroded internal plumbing can run clear, then turn rusty or black. Council notes galvanised pipes, usually found in homes built before the mid-1960s, rust inside with age, and recommends replacing them.
Milky water
Usually air trapped in the pipes, according to Council, rather than a fault in the heater.
During and after a water outage
While a Council water interruption is on, Council suggests not running water-dependent appliances, hot water systems included. When supply returns, open the cold taps slowly to release trapped air. Check Council's interruptions map before booking a plumber for a sudden loss of pressure or hot water.
What you can safely do, and what to leave
You can
- Turn the power off at the switchboard, or the gas off at the unit, if it's leaking or tripping.
- Close the cold water valve that feeds the system to stop a leak.
- Photograph the label: brand, model and manufacture date.
- Note when the problem started and whether the cold water is also affected.
Leave to a licensed plumber
- Thermostats, elements, burners and pilot assemblies.
- The temperature and pressure relief valve, its drain line and any pressure limiting valve.
- Tempering valves and anything on the tank itself.
- Any gas part, which needs a licensed gasfitter.
When the relief valve won't stop dripping
A relief valve that keeps discharging, or a tank that weeps, can be a pressure problem rather than a worn part. Building Commission NSW says its inspectors commonly find heat pump systems installed without a pressure limiting valve, and that excess pressure may make the relief valve fail or the tank leak. They also find relief drain lines ending where they could scald someone or damage the building.
Ask the plumber to test the incoming pressure and check the drain line, not just replace the valve. For other faults, our hot water repairs guide lists the usual suspects.
Repair or replace, and the rules
Council's charter makes the hot water service the owner's to maintain and repair. A repair keeps your existing system and its setup. If the plumber recommends replacing the heater, NSW then requires a temperature control device on the new one, even for a like-for-like swap.
Either way, ask for a Certificate of Compliance when the work is done; NSW requires one at the completion of plumbing work. Swapping a whole system is minor work, so no notice of work goes to Council beforehand.
What we would do
Write down the symptom and when it started, check Council's interruptions map, and turn the unit off if it's leaking. Then get a hot water repair specialist to find the cause before anyone mentions a new system. If the relief valve is the issue, ask about water pressure as well, because a new valve on an over-pressured system may not last. Keep the certificate for whatever is replaced.