There is no reliable single price for running hot water or taking a shower. The cost varies with the amount of water used, the temperature rise, the system type and efficiency, and the household’s current water and energy tariffs.
A longer, hotter or higher-flow shower uses more water and energy. Fixed water service and daily energy supply charges still appear on the bill, but one extra shower does not change those fixed charges.
How much water does a shower use?
A 10-minute shower uses about 60 to 120 litres at a flow rate of 6 to 12 litres per minute. A showerhead labelled at 9 litres per minute uses about 90 litres over 10 minutes.
Check the WELS label for the rated flow. Compare current usage charges on your bill with the Sydney Water prices page, as tariffs change.
What affects water-heating cost?
Water-heating energy depends on the volume used and the difference between the incoming water temperature and the delivered temperature. System efficiency, pipe heat loss and storage heat loss also affect billed energy.
Electricity plans bill usage in kilowatt-hours, while gas plans use their applicable gas usage unit. Compare the variable usage rate on the current bill. Current NSW electricity and gas offers can also be compared through the Australian Government’s Energy Made Easy service.
System type matters. Continuous-flow units heat water while an outlet is running, while storage systems maintain a reserve and reheat it according to their controls. Choosing the right hot-water system size and understanding continuous flow helps avoid an undersized or poorly matched system.
Should the hot-water system stay on?
For most occupied homes, leave the system operating as configured by the manufacturer, installer and energy plan. Repeatedly switching it off for short periods is unlikely to help and can leave the household without hot water.
A continuous-flow unit heats water on demand, although its controls may remain powered. Storage electric, gas, heat-pump and solar systems use thermostats, timers or controlled-load schedules to manage reheating. Do not alter electrical wiring, gas controls, relief valves or thermostats yourself. Setting a safe hot-water temperature is a job for the appropriately licensed trades where adjustment requires access to regulated components.
For an extended absence, follow the manufacturer’s shutdown and restart instructions or ask a licensed plumber. If the system is leaking, smells of gas, has wet electrical parts or shows another immediate hazard, keep clear, isolate the relevant supply only if it is safe, and seek urgent professional help.
What changes the running cost?
- Flow and duration: Higher flow and longer showers use more water and heating energy.
- Temperature rise: Hotter delivered water or colder incoming water requires more energy.
- Tariff: Variable usage rates differ by provider, plan and time of use.
- System performance: Efficiency, storage losses, pipe heat losses and faults affect consumption.
- Household pattern: Consecutive showers and simultaneous outlets change peak demand.
An unexplained increase can also indicate a running fixture or hidden leak. Start with checks for an unexplained rise in your water bill, then arrange testing if consumption remains abnormal.
Shorter showers and an efficient showerhead reduce variable water and energy use. If the system’s performance or consumption has changed, contact our Sydney hot-water service for an assessment by an appropriately licensed plumber.