How to Drain a Pool: WASTE Setting, Pump or Hose, and Time

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How do I drain my pool? Turn the pump off, set the filter valve to WASTE, run the pump until the water is halfway up the skimmer box, then finish with a submersible pump. At one pump maker’s 253 litres a minute, 50,000 L takes 3.3 hours; at Hunter Water’s 1 L/s sewer cap, 13.9 hours.

The short answer

The method: pump off, multiport valve to WASTE, hose to the drain point your water utility allows, pump on. One valve maker lists WASTE for “lowering pool level / draining pool”.
The skimmer line: one pump maker says keep the water at least halfway up the skimmer box and never run the pump dry. Below that, a submersible pump does the rest.
The time is litres ÷ flow: 50,000 L takes 3.3 hours at 253 L/min, 5.4 hours at best with a 400 W submersible rated 9,300 L/h, 27.8 hours at Unitywater’s 0.5 L/s cap and about 7 days by garden-hose siphon at our assumed 5 L/min.
Fibreglass: ask first. One shell’s engineering drawing tells the owner to notify the manufacturer before emptying or partly emptying below the skimmer box.
The destination is not yours to choose: Sydney Water says sewer, never stormwater; Water Corporation in WA says domestic pool drainage is not permitted to sewer.

How long a pool takes to drain, by method, at the flow stated: a 10,000 litre partial drain and a 50,000 litre pool emptied. Flows from one pump maker’s turnover table, Hunter Water’s and Unitywater’s sewer caps, one retailer’s 400 W submersible listing (maximum at zero lift) and our own hose-siphon assumption. Our arithmetic: hours = litres ÷ litres a minute ÷ 60. Read 22 October 2026
Method	Flow assumed	Where the flow comes from	10,000 L (partial drain)	50,000 L (empty)	The catch
Pool pump, valve on WASTE, high speed	about 253 L/min (4.2 L/s)	One pump maker’s turnover table: 50,000 L in 3.3 hours on high	about 40 min	3.3 hours	Drains only to halfway up the skimmer box, or lower only through a main drain; never run it dry
Pool pump, valve on WASTE, eco speed	about 123 L/min	The same table: 50,000 L in 6.8 hours on eco	about 82 min	6.8 hours	As above
Any method held to 1 L/s	60 L/min	Hunter Water’s cap for pool backwash to sewer	2.8 hours	13.9 hours	Not while it is raining (Hunter Water)
Any method held to 0.5 L/s	30 L/min	Unitywater’s cap for maintenance water to sewer, 10am–5pm and 10pm–5am	5.6 hours	27.8 hours	14 permitted hours a day, so emptying 50,000 L spans about two days
Submersible pump, 400 W	up to 155 L/min (9,300 L/h) at zero lift	A retailer’s listing; maximum head 5 m	about 65 min	5.4 hours at best	The only method here that empties below the skimmer; real flow falls as the lift rises
Garden-hose siphon	about 5 L/min (our assumption)	Estimate for about 1 m of fall; Sydney Water’s 18 L/min tap test assumes 15 m of mains pressure	33.3 hours	about 7 days	Slows as the level drops; time yours with a bucket

How do I drain my pool? The method, step by step

Use the pool’s own pump for the top of the water and a submersible pump for the bottom. One multiport valve maker’s instruction sheet lists the WASTE position as “pump waste for vacuuming directly to waste, lowering pool level / draining pool”: water goes from the pump straight out of the waste port without passing through the sand.

Decide how much. Most chemistry problems need a partial drain, not an empty pool; how often pool water should be changed works out the fraction from your test results.
Check the destination with the utility on your water bill (the destination section below). The hose goes where they say, not to the kerb.
Fibreglass or a high water table? Stop and ask before going below the skimmer (the fibreglass section below).
Pump off, valve to WASTE. Never move a multiport valve with the pump running. Fit a backwash hose to the waste port and run it to the permitted point, such as the overflow relief gully.
Pump on and stay with it. Hunter Water and Unitywater both require an air gap at the gully, and Unitywater says to keep checking it so water does not reach neighbouring land or council roads.
Stop at halfway up the skimmer box. One pump maker’s manual says the water must stay at least there and the pump must never run dry.
Finish with a submersible pump sitting on the floor, its outlet hose to the same point. Then turn the valve back to FILTER before the pool pump runs again.

The skimmer-line rule: the pool pump drains to halfway up the skimmer box and no further; below that line, emptying a pool is a submersible pump’s job. A pump drawing through a main drain, with the skimmer line closed, can go lower, but the pump maker’s rule is written for the normal set-up: check your own pump’s manual before you try.

How long does it take to drain a pool?

Litres divided by flow. The litres: length × width × average depth × 1,000. An 8 m × 4 m pool averaging 1.5 m deep holds 48,000 L, so the table above uses 50,000 L. The flow is the assumption, which is why the table shows six, each with its source.

Worked: 50,000 L ÷ 253 L/min = 198 minutes, 3.3 hours. The same pool at Unitywater’s 0.5 L/s cap (30 L/min) takes 27.8 hours, and because Unitywater only accepts it between 10am–5pm and 10pm–5am, 14 hours a day, that is two days of permitted windows.

The bucket test: put the outlet hose in a 10 litre bucket and time it. Litres a minute = 600 ÷ seconds to fill: 10 seconds is 60 L/min, exactly Hunter Water’s 1 L/s cap. Do this before you trust any number in the table, including ours.

The siphon row is our estimate, not a measurement. Sydney Water’s pressure test says a garden tap should deliver 18 litres a minute at 15 m of head; a siphon from a pool has roughly 1 m of fall, and flow in a hose rises roughly with the square root of the head, which gives about 4.6 L/min. We rounded to 5. Every hour, the fall shrinks and the siphon slows.

Can I drain a fibreglass pool?

Not without asking the manufacturer first. The engineering drawing for one fibreglass shell, lodged on the NSW Planning Portal, carries “pool emptying notes”: the owner is to notify the manufacturer before attempting to empty or partly empty the pool below the skimmer box, and no responsibility for damage will be accepted by the manufacturer, its agent or the engineer. The same drawing specifies a hydrostatic valve and a standpipe.

One hydrostatic valve maker says its valve will “safeguard and prevent your fibreglass pool from lifting out of the ground or ‘floating’ when the pool water level is low or when there is excessive water under the pool”. That is the mechanism: the water inside holds a light shell down against groundwater outside. Why a pool lifts out of the ground covers what happens when it does, and fibreglass pool problems what to check first.

For a fibreglass pool, the skimmer line is also the liability line: below it, one maker’s drawing puts the risk on the owner unless the manufacturer was told first. A concrete shell is heavier but the same groundwater pushes on it, so a full drain of any pool is a job to plan, not an afternoon.

Where can I drain my pool water?

Where the utility on your bill says, and they disagree. Sydney Water: “Pool and spa water must not enter the stormwater system”; discharge it to the wastewater system with the pool’s pump and a backwash hose, or by siphoning. Hunter Water: backwash to sewer only through an overflow gully with an air gap, at no more than 1 L/s and not during rain. Unitywater: maintenance water to the gully at up to 0.5 L/s in set hours. Water Corporation in WA: domestic pool backwash and drainage “are not permitted to be discharged to sewer”; ask your local government.

The full rules are in draining a pool to the sewer in NSW and draining a pool to the sewer in WA. Whether the street drain is ever allowed, and the fines where it is not, are on can I drain my pool into the street. Lowering a pool after rain, rather than emptying it, is a different job with its own rules.

How to drain a pool without a pump

A siphon: fill a garden hose with water, keep one end under the surface, put the other end at the permitted drain point lower than the pool’s water, and let it run. Sydney Water names siphoning as one of its two ways to empty a pool. It is free and slow: at our assumed 5 L/min a 10,000 L partial drain takes about 33 hours, and it stops altogether once the water inside falls to the height of the outlet. Two hoses halve the time.

What draining a pool costs, and when to hand it over

The pumping is cheap; the refill and the risk are not. What it costs to empty and refill a pool prices the water. If you are emptying for a resurface or a repair, the drain is normally inside that job: ask each contractor who drains it, who manages the groundwater, where the water goes and who carries the risk if the shell moves, then compare pool quotes on the same written scope. Pool resurfacing cost by interior covers the job that usually follows. Builders are listed for Sydney, Brisbane and Melbourne.

Common questions

How do I drain my pool using the waste setting?

Pump off, turn the multiport valve to WASTE, attach a backwash hose to the waste port and run it to the permitted drain point, then pump on. Stop when the water is halfway up the skimmer box and turn the valve back to FILTER.

How long does it take to drain a pool with a hose?

Days. At an assumed 5 litres a minute, 10,000 L takes about 33 hours and 50,000 L about 7 days, and the siphon slows as the level drops. Time your own hose into a 10 litre bucket.

Can I drain my pool to the sewer?

It depends on the utility. Sydney Water says pool and spa water must not enter the stormwater system and should go to the wastewater system, while Water Corporation says domestic pool drainage is not permitted to sewer in WA.

Can I drain a fibreglass pool myself?

Not below the skimmer without the manufacturer’s say-so. One fibreglass shell’s engineering drawing says the owner must notify the manufacturer before emptying or partly emptying below the skimmer box, and that the maker accepts no responsibility for damage.

How do I drain my pool below the skimmer?

With a submersible pump, not the pool pump. One pump maker says the pool pump must never run dry and the water should stay at least halfway up the skimmer box.

Sources

General information only, current at 2026-10-22. 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.