Converting a Swimming Pool to a Water Tank

The art of repurposing is looking at something you don’t want – and turning it into something you do want.

Had enough of that swimming pool? Some people love them but for others, the joy of pool ownership is overshadowed by the cost of maintenance, the need for refurbishment, and those compulsory fences.

Turning pools into ponds is becoming more common (see this Gardening Australia story) and is an example of repurposing – if a giant pond is what you want. In Brisbane, I would be concerned about creating Toad Heaven. And it would mean we still had to keep the pool fences that cut the garden into three.

Some people break up the pool shell and fill in the hole – which can be a good way to create a swamp. Check with the council before you go down that track.

Our solution was to reimagine the pool shell as an unfinished undergound water tank – just waiting for its lid.  So, we found a company to finish the job by putting the lid on, another to remove all the paving surrounding the pool,  a plumber to look after the pipework, and a certifier to ensure it was all council approved.

Pouring the concrete lid
Putting a lid on it! The lid is the strength of the floor in most apartment blocks.

Costs of Conversion

This is not a cheap exercise but you can offset much of the cost against the cost of keeping the pool, or moving house to get away from it. You save:

  • the cost of power for the pump
  • the cost of chemicals and all that stuff you buy from the pool shop
  • your time for maintenance, and/or cost of outsourcing maintenance
  • the cost of refurbishment if your pool is getting on a bit

On the plus side, coping stones and pool fence panels were repurposed as steps and vertical garden supports.

Better still, by creating an outdoor space that you can use every day of the year, you could add value to your property.

A New Garden

The change to the garden was even greater than we expected.

  • We have a new patio or entertainment area.
  • We gained extra planting space where the pavers had been, now you could walk on the surface of the pool/tank instead of around it.
  • The garden seems much larger without the physical and psychological barriers of the fences.
  • The garden design has changed to reflect the new pathways around that corner of the garden.
  • We have a 50,000 litre water tank.

The job isn’t finished yet. Over the next year while we work on the new garden area, we’ll watch how the sun moves and consider options of covering the base, or putting a pergola over the tank. There are so many possibilities compared to a single use area that was only used part of the year.

10 thoughts on “Converting a Swimming Pool to a Water Tank”

  1. Hi, I live in Sydney, and our house came with an inground concrete pool, which I want to convert into a water tank, and build a granny flat over it. However, a couple of structural engineers have said that pool should be filled to capacity all the times or it may crack. I am not finding many engineers who are willing to take up this exercise. It would be great if you could share your thoughts..

  2. We just went for a lid that gave us a patio area.
    I gather empty pools can crack, or rise out of the ground, depending on your soil type. This would be a risk when emptying pools for refurbishment as well, I guess.
    I think building a granny flat over would make it harder to monitor or fix if anything went wrong. You’d also have to make sure that it was strong enough to support the structure. The lids, like concrete floors, are made to different strengths depending on the final use.
    There was a story on Gardening Australia recently about a sensory garden and they’d also built a patio area over a pool. It was in Melbourne I think.

  3. We are in Brisbane and would like to convert our concrete pool, the way you did. Who did you hire? How much did it cost? We are keen to hear back from you. Thanks Briar

      1. Hey Gayle

        I’d be interested in a rough guesstimate as well. I’m looking at conversion costs too!

        Thanks so much for your helpful posts.


        1. It depends on so many things – size and shape of pool, accessiblity, whether you need to lift tiling from around the edge, distance from the house for plumbing, etc. When you add all the different things up, you could be looking at somewhere between $15k and $30k. Sounds a lot but when you add your ongoing costs like electricity, pool chemicals etc and especially pool refurbishment, you can work out how long it would take to pay for itself. No regrets here.

      2. Bruce Marcus Gorry

        Hi Gayle D,

        Im very interested to hear your experience in converting pool to RWT. How long did it take, and were you able to keep the existing water or did you need to remove it because of the chemicals and let it refill?



        1. Hi Bruce,
          The pool had to be emptied so they could do the work. The whole project took several months – mainly in the lead up finding suppliers and then organise a date when they could come and do the job. The actual job took a couple of weeks with gaps in between pouring of concrete and removal of formwork etc.

  4. Hi I’m from Townsville.
    My pool is an awkward kidney shape. Would northtanks come up and do a conversion given the shape and north qld?

    1. I don’t know, you’d have to ask them. Or maybe they can recommend someone in your area. Ours was an odd shape as well. One corner cut off with a feature wall (we kept the wall) and a corresponding part sticking out the other side where the steps were (and still are inside the tank).

Comments are closed.

Scroll to Top