Tank Installation Instructions

Download the PDF Version here.

1. Choose the site

Selecting the correct site for your new tank is critical in providing you with reliable water storage for many years to come. Use the below key tips to help determine the suitability of your ideal tank site.

  • Locate the downpipes from the roof area that you intend to use as the water catchment.
  • Locate the storm water connection point to connect your tanks overflow (if applicable).
  • Measure the available area taking into account the dimensions of the tank you are purchasing.
  • The key measurements being; tank diameter, inlet height & fall (the distance between the gutter and tanks inlet).
  • Give yourself enough space around the tank for any access requirements you may need now or in future (at least 400mm)
  • Consider the tanks inlet, overflow and outlet positions relative to the above.


2. Excavate

It is recommended to start your preparation with a flat level site, we suggest removing the top layer of grass / soil to begin with a solid foundation. Depending on your measurements taken when selecting the site you may need to excavate down further to provide enough fall. Always take care during any kind of excavation and check for underground services prior to commencement of works. Don’t dig blind use Before you Dig -

3. Prepare the base

Your tank must be sited on a compacted level base. We recommend Crusher Dust, Road base or FCR to minimum depth of 50-75mm. The base must be well compacted, level and retained to prevent it washing away over time. Alternatively a level Concrete base suitable to hold the weight of the tank may be used. Concrete slabs are recommended for Slim Line Tanks. The siting of the tank on fill is NOT recommended as subsidence may occur - a 24,000Ltr tank weighs approximately 24,500 kg when full.

4. Site the tank

Depending on your chosen delivery method and available access, our delivery driver may help you to site and position the tank onto your prepared base. See our delivery terms and conditions for full details. When siting the tank take note of the inlet and overflow positions relative to the intended plumbing configuration. Once on the base the tank may need to be rotated or moved to achieve the optimum placement.


5. Plumbing

All plumbing work should be carried out by a licensed plumber or suitably qualified person, this is the responsibility of the purchaser.

The general plumbing requirement will be:
-Connecting the downpipe(s) from the guttering into the tank inlet strainer
-The overflow pipe from the tank should be connected to an adequate Storm water system
-The outlet/valve at the base of the tank can be plumbed to a pump or tap system

Ensure all plumbing and pipework to and from the tank are properly supported and not reliant on the tank for strength. The use of flexible connections or rubber couplings is strongly recommended to absorb shocks and movement. This is particularly important over long distances. Due to the nature of polyethylene tanks they do expand and contract in differing conditions.


Securing Your New Tank

It is recommended that you put at least 25mm of water in to the tank or otherwise secure your tank from being blown away. Tankworld takes no responsibility for tanks being damaged in this way.

Slim Line Tank Installation

Slim Line tanks by design are tall with a narrow base.  All slim line tanks MUST be installed upon a very sound base, preferably a concrete slab.  A slim line tank installation on a soft base could tip over.  Do NOT site Poly slim line tanks directly against a wall as they will expand when full and may place undue pressure against any structure.

Concrete Pad Installation

Reinforced concrete pad, level and greater than the diameter of the tank is a sufficient poly tank base.

Fire Tank Installation

Galvanised Steel Fire Tanks Base: 7mm crushed blue stone rock to a depth of 50-75mm completely boxed in so that material cannot be washed away.

Tank Stand Installation

Tank stand should have hardwood decking with gaps no greater than 50mm. Decking to be supported structurally by bearers strong enough to prevent sagging of decking when tank is full. Pipe work for tanks on stands must be supported by the stand, not the tank, with 30cm flexible rubber hose to allow for any movement. When calculating your tank stands holding capabilities please remember one liter of water is equal to one kilo of weight. Correct tank stand installation is the customers sole responsibility.


Inground Installation

It is not recommended to bury Poly tanks deeper than 400mm.

If a Poly tank installation is deeper then 400mm, a SPECIAL BUILD HEAVYWEIGHT Poly tank is recommended. Please discuss this with your sales consultant.



Please advise us if you need any extra fittings or gate valves. Strainer, Overflow and one brass outlet plus ball valve - up to 40mm - will be supplied with your tank and fitted on delivery. All other plumbing work to and away from the tank is the responsibility of the purchaser. Extra fittings are available on request. Fittings larger than 40mm are available at an extra cost.


Tasmanian Plumbing Code May 2013 Version;

NOTE - All cold water storage tanks used in drinking water installations from 1st July 2013 must comply with part B1, B2 inclusive of appendix C of this code. Tanks made compliant with this standard are covered by the following statement;

“This tank has been manufactured for the storage of drinking water and all materials are suitable for contact with drinking water.”

Tank Maintenance 

Regular maintenance should be carried out on the water tank and related rain water harvesting system, regular inspection of the below items will help you find and fix any issues as they arise.

  • Check your water tank and fittings for leaks or damage.
  • Check your base and surrounding area, remove any build up of vegetation, inspect for tree roots or signs of animals/ rodents which can undermine the tank base.
  • Check your gutters, screens and downpipes.
  • Check your tanks inlet strainer. Remove the strainer if necessary to inspect the tank internally.
  • Clean and disinfect your water tank at least once a year.

WARNING: You should never enter the confined space of a water tank.

The ongoing maintenance of the tank, the base and associated plumbing is the sole responsibility of the owner. 

The overflow pipe must be plumbed away from the tank.  Failure to do so will result in the tank site being undermined and likely cause the failure of your tank.  The long term maintenance of the site is the sole responsibility of the purchaser and is very important to insure maximum life from your tank. Damage or distortion of the tank by site erosion is not covered by warranty.

If you have any doubts about your installation please contact us for advice.