Pool Water Bill Cost: What a Pool Adds Each Year, by City

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An uncovered pool adds about 40 kilolitres a year to your water use, from evaporation alone. At 2026–27 tariffs that is about $136 in Sydney, $112 in Perth and $196 in Melbourne, where the pool pushes an average household into Yarra Valley Water’s dearer second step. A cover cuts it by 90–95%.

The short answer

About 40kL a year uncovered. SPASA says a cover cuts evaporation by 90–95%, saving 3,000 litres a month, which implies roughly 38–40kL a year lost without one.
Sydney: $136.40 a year at a flat $3.41 a kilolitre, or $153.60 if the $3.84 drought rate applies when dam levels fall below 60%.
Perth: $112.36 a year, because an average WA household already uses 243kL a year, past Water Corporation’s 150kL tier 1, so the pool is billed at $2.809.
Melbourne: $195.57 a year, not $153.25. An average Victorian household uses 427 litres a day, just under Yarra Valley Water’s 440-litre step. The pool tips most of its water into step 2.
Covered: about $7–$14 a year in Sydney. A cover on 90–95% of the time leaves 2–4kL of evaporation.

What an uncovered pool adds to a water bill each year at 2026–27 residential usage prices (tariffs read at each utility, 30 September 2026)
	Sydney Water	Water Corporation (Perth)	Yarra Valley Water (Melbourne)
Tariff structure	Flat rate per kL	Tiers by kL used in the bill year	Steps by average litres per day in each billing period
Usage prices 2026–27	$3.41/kL ($3.84 drought rate)	$2.108 to 150kL; $2.809 to 500kL; $5.256 above	$3.8313 to 440 L/day; $5.0268 to 880; $5.8403 above
Average household before the pool (ABS 2023–24, by state)	166kL a year (NSW)	243kL a year (WA): already in tier 2	156kL a year (VIC): 427 L/day, in step 1
Pool, 40kL a year uncovered	$136.40	$112.36 (tier 2)	$195.57 (mostly step 2)
Same 40kL at the lowest rate	$136.40	$84.32	$153.25
Pool, 58.4kL a year (BoM pan rate on a 32 m² pool, an upper bound)	$199.14	$164.05	$293.57 at step 2
Pool covered, 2–4kL a year	$6.82–$13.64	$5.62–$11.24	$10.05–$20.11 at step 2

How much water does a pool use in a year?

Almost all of a pool’s ongoing water use is evaporation. SPASA, the pool and spa industry association, publishes two figures: an uncovered average-sized backyard pool loses around 7mm a day in summer, and a cover reduces evaporation by 90–95%, saving 3,000 litres a month.

Work that backwards. If 3,000 litres is 90–95% of the evaporation, the uncovered loss is about 3,160–3,330 litres a month, or 38–40 kilolitres a year. We use 40kL. That is close to the volume of a whole backyard pool, every year.

For a higher estimate, use the Bureau of Meteorology’s Sydney Airport evaporation pan, which averages 5.0mm a day across the year (1974–2025). On an 8m × 4m pool (32 m²), that is 160 litres a day, or 58.4kL a year. A small exposed pan evaporates faster than a larger, partly sheltered pool, so treat this as an upper bound, not a prediction.

Rain refills some of what evaporates, and backwashing a filter and splash-out add some. We have not put a number on either, because we found none that was not vendor-published. The one-off cost of the first fill is covered in what it costs to fill a pool with water; this page is the recurring cost.

The quotable version: an uncovered Australian backyard pool evaporates roughly its own volume of water every year, about 40 kilolitres on SPASA’s figures.

Why the same pool costs more in Melbourne: the tariff-step effect

Sydney charges one flat price per kilolitre, so a pool’s water costs the same whoever you are. Melbourne and Perth charge more per kilolitre as you use more, and a pool is added on top of what your household already uses. So the pool is billed at your marginal rate, not the lowest one.

Melbourne, worked through. Yarra Valley Water’s 2026–27 water and sewer usage price steps by your average litres per day in each billing period: $3.8313 a kilolitre up to 440 L/day, $5.0268 from 441 to 880, and $5.8403 above that. The ABS puts the average Victorian household at 156kL a year in 2023–24, which is 427 litres a day, only 13 litres under the first step.

Spread evenly, the pool’s 40kL a year is 110 litres a day. The household’s average rises to 537 L/day. Only the first 13 litres of the pool’s daily water fit in step 1; the other 97 are billed at step 2.
Annual cost: 4.6kL at $3.8313 plus 35.4kL at $5.0268 = $195.57. At the headline step 1 price it would be $153.25. The pool costs 28% more than the lowest rate suggests, an effective $4.89 a kilolitre.
Summer is sharper. At SPASA’s 7mm a day on a 32 m² pool, the pool uses 224 litres a day. Over a 90-day quarter that is 20.16kL, and it lifts the same household’s usage bill from $147.37 to $247.36. The pool’s water cost $99.98 that quarter, against $77.24 at step 1 prices.

Perth works on the year, not the day. Water Corporation starts every account in tier 1 at the start of the bill year and moves it up as use accumulates: $2.108 to 150kL, $2.809 from 151 to 500kL, $5.256 above. The ABS puts the average WA household at 243kL a year, so for most households the pool’s water lands in tier 2: 40kL × $2.809 = $112.36. A household that stays under 110kL a year without the pool pays tier 1 prices on the pool’s water: $84.32.

The tariff-step rule: on a stepped tariff a pool is billed at the rate on your next litre, not your first, and because evaporation never stops, the pool keeps your household average in the dearer step for as long as the pool is uncovered.

What does a pool cover save on my water bill?

If a cover is on the pool enough to achieve SPASA’s 90–95% reduction, evaporation falls from about 40kL a year to 2–4kL. In Sydney, the pool’s water bill drops from $136.40 to $6.82–$13.64. In Melbourne, the saving is bigger because the cover also pulls a typical household back under the 440-litre step.

Whether the cover pays for itself depends on its price and whether you heat the pool. That calculation is in what a pool cover costs and whether it pays back. Where water sits among the other running costs (pump, chemicals, heating) is in what a pool costs to run per year, and the levers are ranked in the best way to reduce pool running costs.

One check before you blame evaporation: if the pool keeps losing water with the cover on, you may have a leak. SPASA’s own figure is that one drop per second is 7,000 litres a year. How to tell if your pool is leaking has the bucket test.

The quotable version: a pool cover turns a pool’s water bill from a real line item into a rounding error, about $7 to $14 a year in Sydney.

Does a pool change the fixed charges on my water bill?

No. The fixed service charges are for being connected, not for how much you use. Sydney Water’s 2026–27 residential charges are $26.65 a quarter for water service and $189.88 for wastewater service, the same with or without a pool. Its typical house bill is $387.03 for a 92-day quarter using 50kL. A pool adds usage charges only, which is why this page prices usage.

Two things can change the rate you pay on that usage:

Drought pricing in Sydney. Sydney Water charges $3.84 instead of $3.41 when Greater Sydney dam levels drop below 60%, until they rise above 70%. The same 40kL would then cost $153.60.
Where you live in WA. Regional towns are in water use classes. In the south, tier 3 starts at 301kL and its price ranges from $2.459 to $6.234 depending on the class, so check your class on Water Corporation’s page.

If you are still planning the pool, the water is one of the smaller running costs, but it is permanent. Ask each builder for the pool’s surface area and include a cover in the quote: compare pool quotes, or browse builders in Sydney, Melbourne and Perth.

Common questions

How much water does a pool lose to evaporation each year?

About 38–40 kilolitres uncovered, worked back from SPASA’s figure that a cover cuts evaporation by 90–95% and saves 3,000 litres a month. SPASA also puts summer evaporation at around 7mm a day for an uncovered average backyard pool.

Does a pool increase my water bill in Sydney?

By about $136 a year for 40kL of evaporation. Sydney Water charges a flat $3.41 a kilolitre for 2026–27, so there is no step effect, but the price rises to $3.84 when dam levels fall below 60%.

Why does my pool cost more in Melbourne?

Yarra Valley Water charges by average litres per day: $3.8313 a kilolitre up to 440 L/day and $5.0268 above. An average Victorian household uses about 427 litres a day, so most of a pool’s water is billed at the higher step: about $196 a year instead of $153.

Will a pool push me into a higher tier in Perth?

Probably it already has. Water Corporation charges $2.108 a kilolitre for the first 150kL of the bill year and $2.809 after that. The ABS average WA household uses 243kL a year, so a pool’s 40kL is usually billed in tier 2: about $112.

Sources

General information only, current at 2026-09-30. Pool rules differ by state and by council, and penalty amounts are updated regularly. Confirm your own obligations with your council or a registered inspector before acting.

What does a pool add to my water bill?