How to choose a water tank

Installed above or below ground?

When planning the installation of a rainwater tank or any tank for water storage, it is important to consider where it can be located on your property. In many cases water tanks are installed above ground, especially when the water tank is being installed alongside an existing dwelling. However installing the water tank underground can be a good space saving solution.

water tanks

Water Tank materials – selection criteria

When determining the type of water tank to install, consider:

  • What ground surface preparation is required
  • Whether the vessel can be installed above or below ground
  • How easily the material is to repair
  • What manufacturer guarantee is available

An overview of types of water tanks available

Concrete water tanks

water tanks
Suitability

An ideal in-ground solution. Feature load bearing tank lids, so they can be installed under garages or driveways.
Site Preparation : Compacted cracker dust or compacted sand, stabilised around the edge
In Ground : Yes
Guarantee : Ask your supplier for a written one prior to purchase
Repairable : Difficult to repair cracks if they occur. Consult the manufacturer

Metal/Steel water tanks

water tank

Suitability

Extremely strong water tanks with polyethylene tank linings to prevent corrosion and ensure water quality.
Site Preparation : A concrete base is required or an approved tank stand
In Ground : No
Guarantee : Ask your supplier for a written guarantee for both the material & the workmanship.
Repairable : Yes, seams can be resealed by the manufacturer.

Poly/Plastic water tanks

water tanks

Suitability

Popular due to its lightweight material which makes for easy site preparation and installation. Poly water tanks are now the most common for household use and come in a variety of shapes, sizes and colours.
Site Preparation : A base of cracker dust or sand
In Ground : Yes, consult the manufacturer
Guarantee : Ask for the manufacturers guarantee
Repairable : Yes, consult the manufacturer

Fibreglass water tanks

water tanks

Suitability

Corrosion resistant and sturdy, fibreglass water tanks are a relatively expensive but long-lasting option.

Site Preparation : Compacted cracker dust or compacted cement stabilised sand or concrete pad
In Ground : Consult the manufacturer
Guarantee : Ask your supplier for a written one prior to purchase
Repairable : Yes, consult the manufacturer.

Bladders & other new innovations

New space saving bladders and modular storage systems have been developed in recent years. These water storage vessels provide wonderful solutions, particularly for urban areas.

water tank

Suitability

Space saving option. An ideal for under house or under verandah water storage.
Site Preparation : Compacted cracker dust or compacted cement stabilised sand or concrete pad. The area must be clear of rocks, tiles and other debris. Smooth the ground, leaving a slight fall towards the outlet end of the Sac.
In Ground : Consult the manufacturer
Guarantee : Ask your supplier for a written one prior to purchase
Repairable : Yes, consult the manufacturer.

Choosing the size of your water tank

Factors to consider Things you need to consider when determining the size of your water tank or storage vessel include:
1. Rainfall – how much rainfall you get in your area,
2. Roof area – how large the catchment surface is,
3. Water usage – what you intend to use rainwater for, and how much you expect to use,
4. Site characteristics – how much space you have, and the location you intend to install the water tank or storage vessel.

Calculating the appropriate size

Use the following formula:
Roof Area  X  Annual Rainfall  =  Maximum Available for Capture

Then determine:
Most Days without Rain  X  Average Daily Water Use  = Storage Volume Required on Day One of a Dry Spell

If for example, the most days without rain was 40 days, and the average daily usage was 400L, the volume on hand on Day One of 40 days would have to be 16,000L.

It is very difficult to predict the required volume, because often a dry period will start when the water tank is not full. However, this method provides a guideline, and you can add a safety factor on top of this requirement.

When calculating how big the storage capacity should be, plan the water tank area so that extra storage can be added later if required.

Location for the water tank

It is important to consider the space you have available, whether the vessel is to be installed above or below ground, below the roof-line or above it (eg. on a sloping site), whether you will have one or more water tanks – connected or installed as separate systems, and what ground surface preparation is required.

Source: Excerpts from Rain Harvesting

JoJo Tanks (South Africa) offer a wide range of water tanks to suit every household, business or agricultural need.  See JoJo Tanks’ SMALL VERTICAL TANKS, LARGE VERTICAL TANKS, HORIZONTAL TANKS and LOW PROFILE TANKS as well as STEEL TANK STANDS.

We are authorised JoJo Tanks dealers in South Africa.  Contact us for a quote on the right water tank for you.  Special discounts are available on multiple orders and to our commercial customers.  We will try beat any written quotation!

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