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Siphoning water from the pool?

Just Starting Out

Siphoning water from the pool?

Hi everyone

I am hoping to gain a better understand of something that happened a few weeks ago.  My pool level was a little low so I topped it up (I am NOT a pool expert, in fact I am a complete novice, but learning).  A few days later it was low again, so topped it up.  I probably topped it up five times in two weeks.

So I'm thinking....oh no, a leak!  However it seemed a bit excessive to suddenly have this occur, I could not figure it out.


My son used the hose and left it disconnected from the tap.  When I went to connect it, to once again top up the water level, I noticed water slowly bubbling out from the hose into the garden.  

I had left the open end of the hose submerged in the pool and it appears to have been draining it! question is, when the hose is connected to the tap where is that water going?  I believe my garden taps are connected to my rain water tank....would it have gone in there?

And now that my pool is over flowing, could I submerge the hose again and perhaps fill my water tank???

I realise the pool water has chemicals thought (it's a salt water pool, not sure if that makes a difference).  My tank is connected to the garden and toilets, I believe.  Though knowing the previous owner there's probably nothing connected to the tank......

Many thanks, and sorry for essay!

Bunnings Team Member
Bunnings Team Member

Re: Siphoning water from the pool?

Welcome to the Bunnings Workshop community @Ingy. It's fantastic the have you join us, and many thanks for your question.


That's an interesting situation you have run into there. To answer your question, if your rainwater tank is above ground, you can't use whatever siphoning magic is happening here to fill it with water from the pool. The pressure to fill the tank would far exceed the siphoning occurring. If it is below ground, I'd imagine a pump in the system that might block backflow into the tank. The pressure from the tank filling up would far exceed any siphoning going on with this hose.


I know in some areas of Australia, there is a requirement to fit a one-way valve to the tap from which you fill your pool. I would imagine that in some scenarios, none that I can think of, the pool water might flow back into your drinking water lines. I would imagine what is occurring in your situation is that you have a full water hose, and once your son disconnected it, the end was placed below the water level of the pool and thus draining it through siphoning.


The issue with filling a container through siphoning from a water body is that the filled container needs to be below the water body for it to be siphoned easily. You can siphon to a higher point, though it starts to get a bit complicated. The water needs to be pulled up out of the water and flow down through the hose, and it's gravity that's causing this action. Gravity needs to overcome the opposing force of the water being drawn from the source so there needs to be a long downwards run.


In conclusion, it's a neat phenomenon you stubbled upon, but apart from using it to drain your pool to a lower point in your yard, I'm not sure if you could put it to practical use. Something like the Ozito 350W Dirty Water Submersible Water Pump would be much more proficient at transferring your water and it what I use to drain my pool.


Please let me know if that explanation assists or you have other questions.






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