What does it cost to empty and refill a pool?

The refill, and why it is the smaller problem

This half is arithmetic. Sydney Water's published residential price for 1 July 2026 to 30 June 2027 is $3.41 a kilolitre for drinking water usage, verified at Sydney Water on 20 September 2026.

A kilolitre is a thousand litres, so:

• a 40,000 litre pool is 40kL, which is about $136;
• a 60,000 litre pool is 60kL, which is about $205;
• a small plunge pool at 12,000 litres is about $41.

Two things make a refill cost more than a top-up beyond the sheer volume. Stepped and tiered tariffs mean a large single draw can land in a higher price step than ordinary household use, which is significant in Perth and Melbourne where tariffs step by consumption. And in Sydney, a permit is required to fill a new or renovated pool or spa greater than 10,000 litres, with an approved pool cover as a condition of that permit — a rule we were able to corroborate across several sources but could not read on Sydney Water's own site from here, so confirm it with them before relying on it.

We have worked the fill arithmetic across Sydney, Perth and Melbourne tariffs, including the tier effects, in what it costs to fill a pool with water. This page is about the other half.

The finding: two water authorities say opposite things

When we went looking for the rule on where pool water may be discharged, we expected a national convention with local variations. What we found was a direct contradiction between two state water authorities, each publishing its own position clearly.

Western Australia. Water Corporation states plainly: “Backwash and drainage from domestic swimming pools and spas are not considered as trade waste and are not permitted to be discharged to sewer.” Commercial aquatic facilities are different — they must apply for a Trade Waste Permit before connecting to sewer, and chlorine must not exceed 10 milligrams per litre as residual chlorine.

New South Wales. The position is the reverse. Pool and spa water is chlorinated and needs treatment, so it must not enter the stormwater system and should be discharged to the wastewater system — that is, to sewer — using the pool's pump and a backwash hose, or by siphoning.

South Australia. A third position, and the best documented. The SA EPA's information sheet states that “South Australian legislation prohibits the disposal of backwash water from swimming pools into the stormwater system”. Pool backwash water and pool chemicals are both listed pollutants under Schedule 4 Part 1 of the Environment Protection (Water Quality) Policy 2003, and clause 17(1) provides that a person must not discharge a listed pollutant into any waters or onto land where it might enter any waters. Sewer discharge is permitted: “In areas connected to the sewerage system, backwash water from all swimming pools can be directed to a sewerage drainage point”, with approval from SA Water, and new pools “should be permanently connected to the sewer at the time of installation”.

We are showing you the disagreement rather than resolving it, because resolving it would mean inventing a national rule that does not exist. The practical consequence is simple and important: this is a question for your own water authority, and an answer that is correct in Sydney can be an offence in Perth.

One rule held everywhere we looked: never to stormwater. The reason is physical rather than bureaucratic — stormwater drains discharge to creeks, rivers and the ocean without treatment.

The penalties, and the part that is genuinely enforced

Stormwater discharge is the one that attracts enforcement, and South Australia publishes the mechanism in full.

The general environmental duty under section 25 of the Environment Protection Act 1993 requires any person undertaking an activity that may pollute “to take all reasonable and practicable measures to prevent or minimise any resulting environmental harm”. Failure to comply with the Water Quality Policy obligations “may result in a $300 fine, Environment Protection Order, and/or prosecution”.

The $300 is the least significant part of that sentence. An Environment Protection Order is a direction you must comply with, and prosecution is a separate matter entirely.

South Australian owners are also subject to a further obligation under the Public and Environmental Health Act not to discharge waste in a public place, and under the Code of Practice for Swimming Pools must dispose of filter backwash water “in a way that does not create an offensive situation or nuisance and that is not injurious to health”.

There is a practical wrinkle for properties not on mains sewer. The SA guidance is explicit that backwash and pool water “should not enter the septic tank as it will flood the tank and affect the bacteria necessary for sewage treatment” — it must bypass the tank via a gully trap installed by a licensed plumber, and on a community effluent scheme the council operating it must approve a permanent connection first.

Which connects to a point worth knowing before any of this: the connection itself is plumbing work. Pool recirculation pipework is not, but the point where a drain pipe joins the sewer is, and it requires a licensed plumber — see is pool pipework plumbing work.

Before you empty it: the reason to check the water table first

There is a physical risk in emptying a pool that has nothing to do with water bills or discharge law, and it is the most expensive mistake available on this page.

A pool shell is held down largely by the weight of the water in it. Remove that water while the ground around and beneath it is saturated, and the groundwater pressure outside the shell can exceed the load inside it. Australian pool engineers call the result “pool pop” — the shell lifts, twists, or in severe cases rises out of the ground.

The risk is highest for fibreglass shells, which are light, and highest of all during or shortly after heavy rain or where the water table is high. A concrete shell is heavier and more resistant, but not immune, and a lifted shell is generally not repairable in place.

What Australian pool professionals recommend, consistently:

• Do not drain a pool without establishing the water table first.
• Use the hydrostatic valve if the pool has one — it is there to let groundwater in and equalise the pressure.
• Use the standpipe where one is installed, to check groundwater and pump it down with a submersible pump.
• Do not drain after heavy rain. Wait for the ground to dry.
• Ask a pool professional before fully draining a fibreglass pool. In most cases a full drain is not necessary at all.

That last point deserves emphasis, because it is the cheapest advice here. Most problems people drain a pool to solve — chemistry gone wrong, stains, high stabiliser — can be handled with a partial drain and refill instead. A partial exchange avoids the structural risk entirely and costs less water.

These figures are published by water authorities and pool engineers, not by us. If a pool is being emptied as a step towards getting rid of it altogether, the approval pathway matters more than the water — see do I need council approval to remove a pool and what removal costs. If it is being emptied for a resurface or a renovation instead, what differs between quotes covers which scopes include the drain, the discharge and the refill.

Common questions

Sources

• Sydney Water — residential pricing, 1 July 2026 to 30 June 2027
• Water Corporation (WA) — swimming pool discharge regulations
• SA EPA Information Sheet 181/04 — disposal of swimming pool backwash water
• Pool Engineer — hydrostatic pressure and pool lifting

General information only, current at 2026-09-20. 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.