Running a pool under worsening water restrictions


Well-known member
Jan 8, 2013
Sydney, Australia

In 3 days Sydney moves to level 2 water restrictions.

Has anyone built a system to save backwash water, basically a holding tank and some sort of method to get the water into a state so that a large percentage of it can be slowly put back into the pool?

Maybe the holding tank has a cartridge filter on its outlet to the pool?

Backwash Recyclers Australia comes up on Google as somebody with a system but I would rather DIY it.



Well-known member
Jan 8, 2013
Sydney, Australia
Thanks, you mean put the backwash into a rain water tank, or are you saying to just put rain water into the pool, I already have a rain water tank, it's been empty for over a month?


New member
Mar 30, 2018
South Africa
We have just been through the most severe droughts and water restrictions experienced in Cape Town, South Africa.
Here most people purchase 2 X 500L water tanks.
The tanks usually have a hole for an outlet tap about 25-30cm from the bottom.
The idea is to backwash into one tank, and when it is almost full to begin filling the other.
Once a tank is full, shock the water with chlorine and leave the water in the full tank undisturbed so that all the sediment settles to the bottom. After a week or so (or when the other tank is nearly full), begin feeding the water back into the pool or another water tank containing only clean water. Some people filter this water also before re-introducing it to the pool.
When the clean water is all used up, the lower part below the outlet is usually flushed to waste with most of the settled dirt.
The process is then repeated with the other tank.

Personally, I installed a cartridge filter as it requires no back-washing.
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Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
@rthorntn you show a cartridge filter in your signature, so you should not be backwashing.
Also be sure you let your filter pressure rise by 25% over clean pressure before cleaning the filter.
Do you have your pool covered? The greatest loss of water is due to evaporation.


Well-known member
Jan 8, 2013
Sydney, Australia
Thanks all, I'm just exploring options, the low maintenance of a sand filter without the backwash filter loss would potentially be ideal.

I don't have the pool covered, it's a really old fashioned shape of pool and would need a custom cover, the price versus the life expectancy of it freaked me out, Australia is an expensive country, might be time to revisit this, any tips?

Costas > DownUnder

Bronze Supporter
Dec 17, 2017
Adelaide | Australia
Question will be as to how often will you be finding the need to backwash.

I have a 36000L sized pool. I only backwash in winter relying on rain to fill the pool before commencing a backwash. So I use no tap water for backwashing

Reason I can do this is down to three parameters:

1 - I use hairnets in my skimmer to pre-filter the water before it gets the filter.

2 - I use a Waterco multiclyclone pre-filter at the output of my pump to trap even finer debris.

3 - I selected the largest sand filter that I could fit in the equipment room. The larger the filter, the longer you can go before the need for backwashing arises.

In practice I find that I only ever need to backwash when the water level becomes too high due to rain rather than waiting for a 25% increase in filter pressure.

Evaporation is the largest user of water and only a cover will help here.
Last edited:


Well-known member
Jan 23, 2018
Canberra ACT
I read up on those level restrictions at least you not stopped from topping up even if limited to 15 min a day. i have 26k liter AGP. last summer (1st time up) evaporation and splash out used far more water than the few backwashs i did on the 21" sand filter.
This year i've plumbed in a 32" sand filter that with nice clear TFP water and vacuuming via a leaf catcher canister i expect to not backwash till winter now.

As for the cover you could buy a couple of cheap solar covers from ebay and cut up into sections, even 80% coverage would stop quite a bit of evaporation.