What to consider when installing a rainwater tank

Costs

• Delivery (actually getting the tank to where you want it)
• Installation
• Gutter, roof and downpipe alterations/connections 
• A solid level foundation or tank stand for tanks to sit on
• Excavation work for below ground tanks
• Backflow prevention devices (When connected to toilets or washers)
• First flush device, screens and gutter guards
• Extra plumbing to and from tank
• A pump if needed
• Maintenance

Typical tank installation costs 

Note: Actual costs will depend on each individual site.

Location and Usage

There are many factors that will determine the most appropriate location of your rainwater tank. Maintek recommends that you walk around your house and note the locations of your downpipes. The closer the tank is to a downpipe, the simpler and cheaper the installation will be. Once you have selected an appropriate site, you can begin to prepare this site for the tank. level ground will mean there is little or no preparation involved just carry the tank in and make the connections.

How much water do we use in and around the house?

How much water will I collect?

The amount of rainwater you will collect is dependant on a number of factors, including:

• The size of your roof – including pitch and shape.
• The size of your tank.
• The amount of rainfall on average in your area.
• The number of down pipes you have leading into the tank.

A good way to estimate the water you can potentially harvest in one year can be worked out in the following formula.

• Q = 0.7Ai   Where: Q= run-off in one year (litres)
• A= connected roof area (m2)
•  i = annual rainfall in your area (mm)
• 0.7= coefficient that allows for losses such as evaporation and overflow
• For example 800mm per year on a roof area of 150m2 would equal 84,000Lt per year or 1615Lt per week!

What is the best way to use my stored rainwater?

There are many ways to use your stored water, with current water restrictions in Sydney the most effective ways to use rainwater is to water the garden, wash the car or house, flush your toilets or in the washing machine.

Can I drink the water from my tank?

In rural areas where the traffic and pollution levels are lower water quality is generally higher. But in heavily populated urban areas it is not recommended that you drink the water from your tank due to higher levels of airborne pollutants.

What Base do I need to prepare for my tank?

You can place your tank on a bed of sand, a concrete slab or a tank stand:

1. Stand - Only tank stands with a hardwood decking spaced no more than 50mm apart should be used. Bearers must have sufficient strength to prevent deflection when tank is full.
2. Sand - A 50-100mm sand bed is an ideal base. Ensure the sand bed is 200mm wider than the diameter of the tank and that the sand cannot be eroded from under the tank. i.e.. timber surround and direct overflow away from the tank.
3. Concrete - Tank may be sited on a level concrete slab slightly wider than the diameter of the tank.

What is the height of a tank stand?

A tank stand is 200-1000mm high and is 100mm wider than the tank.

What pump do I need for my house?

The pump you need depends on the number of people in your house and what you intend to use the pump for.

Maintek can provide you with a range of pumps to assist you in dispersing your stored water in and around your home. Pump options include:

• Low Volume Pressure Pumps to service 2 taps.
• Pressure Pumps for small (3 taps), medium (4 taps) and large (5-6 taps) homes.
• High Volume Pressure Pumps to service 7 taps.
• Transfer Pumps – to move stored water from one location to another.
• Submersible Pumps – to place inside your stored water supply.