couple looking at hot water bill

Calculating Your Adelaide Hot Water Bills

Are you one of the average Adelaideans spending $324 per quarter on your water bills according to Canstar Blue in 2020? Hot water can be more expensive than you’d think and that doesn’t include the energy required to heat the water!

How exactly are your Adelaide hot water bills calculated? And how can you be more water and energy efficient so you can save when those bills come round?

Average Household Water Usage Per Day Australia

Your water bill is directly correlated with how much water your household uses. Your household’s water usage also depends on the number of people in your home, how efficient your appliances are and even what time of year it is.

seasonal water use in adelaide
Breakdown of seasonal water use in Adelaide. Source: SA Water

While your quarterly water bills will change throughout the year depending on the season, you can safely assume that on average over 12 months you will use 190 litres of water per day.

The last census in 2016 found that there were 2.5 people per household in Adelaide. This means the average Adelaide household uses 475 litres of water per day. If we round this up to three, this increases to 570 litres per day.

Water usage varies greatly with the seasons, so you can expect this number to increase in the warmer summer and autumn months and decrease quite significantly come winter time. We use almost three times as much water in summer than we do in winter!

Average Water Bill Adelaide

SA Water currently has a three tier pricing model, where the more water you use, the more expensive per litre your water is. This model incentivises Adelaide residents to be mindful of the water they use to reduce their annual water bill cost.

This system is based on the average water used per household per day, in kilolitres (kL). Depending on how much water you use, you fall into one of the three tiers.

These tiers apply all across South Australia, so whether you live in regional SA or metropolitan Adelaide, you’re paying the same rates. SA Water has also reduced the three tiers for 2020-21 by approximately 18% from previous years.

Tier Price per kL Daily threshold (kL)
1 $1.945 0 – 0.3836
2 $2.775 0.3836 – 1.4247
3 $3.007 Above 1.4247

SA Water three tier pricing model. Source: SA Water

SA Water charges you for your water the same way you are taxed. For example, if your water use falls into tier two, you pay tier 1 prices for all the water you use up to the daily threshold of 383.6 litres, or 0.3836 kilolitres. Anything beyond this, but up to the upper 1424.7 litre limit for tier 2, is charged at the tier 2 price.

You also need to factor in the fixed $271.40 for the SA Water supply charge. Per quarter you pay $67.85 for this. This fixed price has been reduced 10% from previous years.

You pay for access to the water mains regardless of whether or not you are connected. SA Water charge you a “rating on abuttal” for having readily available access to the water mains. This cost varies between properties.

Below we’ve compiled your expected average water bill based on the average daily water use per person in Adelaide. This indicates that the average water bill per quarter in Adelaide for households with 2.5-3 people will cost somewhere between $135 and $182.

People in Household kL Per Day Tier Cost ($) per kL Cost ($) Per Day Cost ($) Per 91 Days Fixed Cost ($) 91 Days Total Cost ($) 91 Days
1 0.19 1 1.945 0.37 33.63 67.85 101.48
2 0.38 1 1.945 0.74 67.26 67.85 135.11
3 0.57 2 2.775 1.26 114.97 67.85 182.82
4 0.76 2 2.775 1.79 162.95 67.85 230.80
5 0.95 2 2.775 2.32 210.93 67.85 278.78
6 1.14 2 2.775 2.85 258.91 67.85 326.76
7 1.33 2 2.775 3.37 306.88 67.85 374.73
8 1.52 3 3.007 3.91 356.19 67.85 424.04
9 1.71 3 3.007 4.49 408.19 67.85 476.04
10 1.90 3 3.007 5.06 460.18 67.85 528.03

Breakdown of SA Water pricing based on the average 0.190 kL of water used per person, per day.  The 2-3 people in household rows have been highlighted to indicate the average Adelaide household. 

This model is effective for SA water as while they try to read your water meter every 91 days, this isn’t always the case. Your water meter has the date of your last reading and so it only takes a simple calculation to determine your average daily water use for that quarter and which tier you fit into, regardless of how much time has passed since your last reading.

Adelaide Hot Water Bill Average

Now that we know how you pay for your Adelaide water bills, we can get into the average hot water bill. On top of your water bill, you need to also add in your energy costs when calculating the cost of your hot water.

Your hot water system uses nearly a quarter of your home’s total energy. This is second only to heating and cooling which is very energy intensive at 40%.

pie chart of energy usage in Adelaide households
The average energy used in Adelaide households around the home. Source:

That said, there are a wide range of factors that will affect the average hot water bill:

  • Energy source – gas, electric, solar, etc.
  • How water efficient your fixtures and appliances are
  • Which appliances use hot water
  • Type of water heater – storage tank or continuous flow
  • Number of people in the home
  • Water heater temperature setting

SA.GOV.AU has a calculator you can use which can provide you with an estimate of running costs and lifetime costs for your hot water bills. This is based on the number of people in your home and their water habits.

Gas Vs. Electric Hot Water Running Costs

Here in Adelaide, gas has always won the gas vs. electric hot water running costs debate. Canstar Blue says the average electricity and natural gas rates in Adelaide are 42 c/kWh and 4.2 c/MJ respectively. Our electricity rates are the highest in the country while our gas rates are the second cheapest.

At face value, natural gas is ten times cheaper than electricity, however, these are completely different units of energy. It’d be like comparing apples to oranges.

Firstly there’s the fact that 1 kWh does not equal the same amount of energy as 1 MJ. The typical electric oven runs at 2.3 kWh while the typical gas oven runs at 12 MJ. This means that for household appliances, 1 kWh is approximately equal to 5.2 MJ.

If we were to take two comparable Rinnai water heaters – a 160 L electric storage tank with 3.6 kW and a 170 L gas storage tank at 20.5 MJ, we can calculate their approximate hourly running costs with the below formulas.

formulas to calculate running cost of hot water per hour

Using these formulas, the electric hot water system runs at 151 cents per hour while the gas alternative only uses 86.1 cents per hour. In this scenario, the electric water heater is 57% more expensive to run than the gas water heater! You can calculate the running cost of your own water heater if you know the kWh or MJ using these formulas.

You can multiply the cost per hour by the number of hours the water heater is in use to determine its daily running costs. Multiply this by the number of days it’s turned on and you’ve got the annual running cost too.

This doesn’t account for control-load tariffs which can reduce the cost of electricity, however. If you have a solar water heater, this will cost much less to run than electric water heating as well as gas water heaters!

The average moderate hot water user will go through 76 litres of hot water per day. For a tier 1 SA Water user, this is a mere 15 cents per day to supply the water to be heated. For tier 2, this increases to 21 cents and 23 cents for tier 3.

Multiply this by 2.5 for the average number of people per household, and the cost to supply your water before it is heated comes to 37.5 cents, 52.5 cents and 57.5 cents for tiers 1 to 3 respectively.

Then we need to add in the cost of heating this water. The average hot water system runs for approximately three hours per day. For the gas water heater running at 86.1 cents per hour, you’ll be paying 258 cents for the three hours every day. For the electric water heater running at 151 cents per hour, you’ll be paying 453 cents per day.

Combining the cost to supply water and heat it is the total cost of your hot water. The average Adelaidean with a gas hot water system will pay between $2.95 and $3.15 per day for hot water. Those with electric units will be up for quite a bit more, forking out between $4.91 and $5.11 for hot water every day!

bar graph of electric vs gas daily hot water costs
The total daily cost of hot water for electric and gas storage hot water systems based on the average water and energy use per day in Adelaide.

How to Reduce Water Usage at Home

One way you can reduce your average cost of water per year is by adopting some good water-saving habits across the home. If you understand where most of your water goes in the home, you can target areas where changes will have the greatest impact.

pie chart of water usage in Adelaide households
The average water used in Adelaide households around the home. Source:

60% of an average Adelaide household’s water is used inside, while the remaining 40% is in the garden and outdoors. It’s unlikely your plants will be happy with less water than you’re already giving them, so it’s best you start looking indoors to reduce the amount of water you use.

A third of you indoor water goes straight to baths and showers. You can easily cut back on your water use by reducing the time you spend in the shower and installing some water-saving shower heads.

Save water in the laundry by making sure you only use your washing machine when you have a full load. You can apply this same principle for your dishwasher in the kitchen! If either of these appliances is especially old, upgrading to a newer model will likely reduce your energy and water use too.

Running toilets and leaking taps will also increase your water bill. Get a plumber out to repair these – a leaking tap alone could waste 19,000 litres in a year! That’s an additional 52 litres per day you could be paying for which could bump you up to the next pricing tier!

How much water is wasted in Australia?

Here in Australia, 80% or more of household water leaves as wastewater, essentially wasted.

Much of this water can be treated and reused, helping us to waste less water. Water suppliers across the country are increasingly using recycled water where they can.

SA Water supplies recycled water to a number of areas in Adelaide:

  • Adelaide parklands
  • Bowden residents
  • Southern suburbs of Adelaide
  • Mawson Lakes
  • Virginias’s market gardens

This recycled water is perfect for flushing the toilet, watering the garden, washing the car and more but shouldn’t be used for for drinking, cooking or washing yourself in.

How to Reduce Hot Water Bills

If you’re taking steps to reduce your overall household’s water use such as having shorter showers and installing water efficient fixtures, you’ll naturally start reducing your hot water bill too. There are more steps you can take, however, to cut back the cost of water heating and your energy bills.

The easiest place to start is to stop using hot water where you don’t need it. Does your washing machine really need to use hot water, or would cold water suffice? Many dishwashers have an eco setting that will use less hot water too.

If this isn’t saving you enough on your hot water bill and your water heater is ten or more years old, it’s time to get a plumber out to install a new one. Over time your hot water system will become less energy efficient with general wear and tear.

Newer models also have more advanced water heating technology and will inherently be more energy efficient than a brand new, but older model. If you still have an old storage tank variety of water heater, having a new continuous flow model installed will significantly help you save on your hot water bills.

For systems that aren’t too old, it’s important you have them serviced annually. This will ensure they are still running efficiently and that you won’t be up for costly repairs unexpectedly.

There’s no escaping your Adelaide hot water bills, but there are definitely many ways you can go about reducing them. If it’s time to upgrade that old water heater, you’ll need a trusted name in the plumbing industry.

Call us today for an expert hot water installation and services with interest free payment options**!

FAQ – Everything You Need to Know About Adelaide Hot Water Bills

Have a question about Adelaide hot water bills? We’ve got you covered with all your FAQ here.

According to Canstar Blue, the average Adelaide water bill is $324 per quarter. Your bill will vary with the amount of water you use.
For those with electric water heaters, hot water accounts for 23% of your electricity bill.
If your water heater uses natural gas as its energy supply, then yes your gas bill will include the energy used to heat your water. It does not include, however, the supply of water that is heated.
SA Water has two components in their quarterly hot water bills - a fixed supply charge of $271.40 split up quarterly into $67.85 and a variable charge for the amount of water you use. The more water you use, the more you pay for this variable portion.
A kilolitre is a metric of volume of liquid or gas. 1 kilolitre equals 1000 litres.

Published: 5 Mar, 2021

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