So you are looking at buying a water tank. There are a number of things you need to consider before making a decision.
What are you going to be using the water for.
There are generally 4 main things that water storage is used for. That is:
- household use
- irrigation/ reticulation
- stock water and
- fire water.
The use effects where you place the tank on your property, how much water you need to have stored and how often you are filling the tank. If the water is for household use, then the water needs to be clean and potable and the tank needs to be built near your house. If it’s for irrigation, then the water needs to be low in salt and the tank needs to have sufficient volume so the pump for your irrigation system can run the system properly. If the tank is used for stock water, then the tank needs to be placed in a high point on the property so that if there is a power failure, then the troughs can fill under gravity. In addition, the tank needs at least a couple of days supply in it so if there is a pump failure, then there is enough water to get by while repairs are carried out. Lastly if the tank is to be used for firefighting, then there needs to be a fast way to fill trucks and appliances and enough volume to protect your property for at least 4 hours. As well as that, if the tank is to be filled from a river or bore, then the pumping gear needs to be able
to run easily from an independent power source.
How much water will you be using.
The next thing to consider how much water you will be using. That is how much you are using on a daily, weekly or annual basis. If the tank is for your house and is filled with rainwater, then you need to collect enough water to get your family through the dry season and then being refilled from your roof catchment during the rainy season. If you are using the water for stock, then there needs to be sufficient volume to provide a supply to the animals for their daily requirements while having a buffer to allow for pump or supply breakdowns. If the tank is to be topped up from a river, dam or bore then the tank needs to have a temporary supply so that if the herd or flock all drink at once, the the supply is not starved. When considering a tank storage for irrigation, then the tank needs to have sufficient buffer in it so that the irrigation pump does not run dry when watering your garden or orchard. You may not need to have a whole cycle worth of water stored in the tank, especially if the fill volume of the tank is reasonable and can partly keep up with the pump volume.
What is you water source to fill the tank.
There are 4 main sources of water that are used rainwater, dam, river and ground water. Where you place your tank and how you plan to fill it from your water source will affect the choice of materials and the size of the tank. If you plan to slowly fill a stock water tank from a bore with a solar pump or windmill, then the tank needs to be high up on a hill or a stand and a large tank can be difficult to get up in a high place sometimes with a small footprint. If you are going to fill the tank from rainwater then the top of the tank needs to be lower than the roofline of the buildings that you are filling the tank from. If this isn’t possible, then a smaller sump or tank is needed to catch the water, then a pump can be used to move the water up to a storage tank. Another aspect that gets overlooked is the water quality. If there is a large amount of sediment in the water as dam and river water can quite commonly have, then it should first be filtered or at least strained so that larger pieces of material don’t become stuck in the tank. A simple way to clean out the tank should also be considered as this will make removing built up sediment much cheaper and quicker. This is usually done with a large flush valve right on the floor or a scour valve which is usually plumed into the centre of the tank floor with an outlet on the downhill side.
Where do you want to install the tank.
The position of a tank is very important for its function and maintenance. A general rule of thumb is that a tank should always be installed at the highest point of a property so that the water in it is under gravity and can be used even when the power is out or the pump is broken. This is especially important if it is to be used for fire water. It also makes a very efficient stock watering system as gravity will keep troughs full with no power or pumps needed. If the tank is to be used for rainwater harvesting, then as per before the top of the tank needs to be below the roofline of the catchment building (house or shed) so that the tank will fill up completely. Another aspect of location is if vehicles need to get close to the tank for emptying, filling or maintenance. This is common for farm vehicles like boom sprayers or for fire appliances. If the tank is on the top of a steep hill yes the water is under gravity but it can be slow and dangerous to get up there to get water out of or into the tank.
Have you got the pipes, pumps and power in place yet?
Another aspect that needs to be considered is the important things that make your tank work, the electricity, pumps and pipes that get the water out of your tank or fill it up. Especially if it has not been installed yet, an electricity supply can be complicated and expensive to get set up and may even surpass the cost of the whole tank and site works! In addition, there simply may not be available supplies where you want them or enough Amps available to run larger pumps. Placing your tank up on the highest point of the property so that you can take advantage of gravity does sound like a good idea, but this hill might be 2km away and a nightmare to run pipe up to it. It might be more efficient to place the tank at a lower but much closer point on the property and then if really 
needed, a pump can be used to provide pressure or transfer large amounts of water.
As you can see there are a lot of different things to consider when looking at installing your new tank. At Southern’s we try to take the guesswork out of this by using our experience and knowledge to help you solve your water storage dilemmas. Give us a call on 9721 3577 or email us today and we can help guide you through the tank installation process.