Choosing a system
What types of hot water system are there?
Five main types are found in Sydney homes: gas storage, gas continuous flow, electric storage, heat pump, and solar with a gas or electric booster. Each heats water differently, costs a different amount to buy and run, and suits different homes. Our home page has a quick comparison table, and each type has its own page: gas hot water, electric hot water and heat pump and solar.
Which is the cheapest to run?
For the same amount of hot water, a heat pump generally uses the least purchased energy of the electric options, and solar can be cheapest where the roof and climate suit it. Gas running costs depend on gas prices. A standard electric tank on a continuous tariff is often the most expensive to run. Your household's use and tariffs make the real difference, so ask for an estimate.
Which is cheapest to buy?
Usually a like-for-like electric storage tank, followed by gas storage. Continuous flow, heat pump and solar cost more upfront. See the 2026 cost guide.
What size do I need?
For storage tanks, think about the number of people and how many showers happen close together, and whether the tank is on an off-peak tariff (which needs to last a full day). For continuous flow, think about how many hot taps run at once. Tell the plumber how your household actually uses hot water.
Replacing a system
How long do hot water systems last?
Many storage tanks last somewhere around 8 to 15 years, depending on water quality, the anode, temperature setting and use. Some last longer, some fail sooner. Continuous flow units and heat pumps wear differently and are often repairable.
Can I replace a hot water system myself?
No. In NSW, installing a hot water system is plumbing work, connecting gas is gasfitting work, and electrical connection needs a licensed electrician. Unlicensed work can void warranties and insurance and can be dangerous.
What paperwork should I get?
A certificate of compliance for the plumbing work, and for gas work if any, plus the manufacturer's warranty and an itemised invoice.
Do I need council approval?
Replacing an existing hot water system is generally exempt development in NSW, subject to conditions, such as noise limits for heat pumps. New positions, heritage properties and strata buildings may need more. Check with your council or owners corporation if unsure.
Rebates and incentives
Are there rebates for hot water in NSW?
The NSW Energy Savings Scheme has offered discounts on eligible heat pump installations, and the federal Small-scale Renewable Energy Scheme provides certificates that reduce the price of eligible solar and heat pump systems. Conditions and amounts change, so check Energy NSW and the Clean Energy Regulator at the time you buy. Ask the installer to show any discount as a separate line.
Who is eligible for free hot water systems?
Offers of "free" systems usually come from incentive schemes and their conditions. Be careful with door-to-door or phone offers. Check eligibility with Energy NSW directly before signing anything.
Repairs and problems
My hot water has stopped. What should I check?
Check the circuit breaker for electric systems, the pilot or error code for gas, and that gas and water are on. If anything trips repeatedly, or you smell gas, stop and call a professional. Our guide to the day your hot water fails goes step by step.
Water is leaking from my tank. What do I do?
Turn off the cold water supply to the unit and the power or gas, then call a plumber. If the inner tank is leaking, it cannot be repaired. See hot water repairs.
About this service
Who does the work?
Hot Water System Sydney is a referral service. Work is carried out by independent local contractors. We ask the contractors we work with to hold the licences and insurance the job needs — ask to see them before work starts. See about us and the disclaimer.
Which areas do you cover?
Sydney, with local lines for Liverpool, Penrith, Blacktown, Castle Hill and Baulkham Hills.
Questions people ask before they commit
How do I find out how old my hot water system is?
Look for the data label or compliance plate on the unit. It usually shows a manufacture date or a serial number that encodes the date. The installation date may also be on a sticker or the original paperwork.
What temperature should my hot water be?
Storage tanks need to keep water hot enough to control bacteria, generally at least 60°C. Water delivered to bathrooms in new and replacement installations is generally limited to a lower temperature, commonly 50°C, by a tempering valve. A plumber can confirm what applies.
Do I need to be home for the replacement?
Someone usually needs to provide access, confirm the position, and see the system running at the end. Arrange this with the contractor.
Can a hot water system be installed on a strata property?
Yes, but the owners corporation may need to approve some work, especially changes of position, new external units or gas work affecting common property. Check the by-laws first.
Who regulates plumbers and gasfitters in NSW?
NSW Fair Trading licenses plumbers and gasfitters and handles certificates of compliance. You can check a licence on the NSW Government licence check service.