Very few Councils require you to get permission to install a steel or poly tank with capacity of less than 5000L. A large plastic slimline tank is 3000L.
Schedule 4 of the Building Regulations 2012 requires a building permit for all rainwater tanks with a capacity exceeding 5,000 litres, primarily to show that the structure will be safe.
We would typically submit form BA2- Uncertified Application - accompanied by approved drawings from the tank manufacturer verifying the structural integrity of the model to be installed.
Most councils will have a condition that says that the tank must be in the back garden of the property and to maintain visual amenity must not be visible from the front street. If the tank is against the fence line then a height limit of around 1.8m generally applies. Tanks can be set down into the ground by a few hundred millimetres to reduce the overall height if this is important, but this is more often done to create a level platform or to drop the height below a gutter.
A planning application may be required for a large tank (for example a 90,000L or larger steel tank on a rural property) if it is outside the 'building envelope'. Development inside this area generally does not require a separate application. If planning a new house it makes sense to include the location of tanks on the original application to save having to go back to Council later.
Installing a rainwater tank rather than soakwells
Stormwater must be retained on the vast majority of properties in WA and cannot be released onto the street or a neighbour's property. There is a standard formula for the sizing of soakwells to retain this water, and they are expensive to install. Many councils are amenable to rainwater tanks being used to replace some of the soakwell capacity, and the tank may well cost less.
Your rainwater tank is very likely to overflow in the winter because you can't use the water as fast as it's being collected on wet days. It will need to drain somewhere - either to a soakwell or a sub- surface drain. If neither of these exist we can install the most appropriate system.
Rainwater or stormwater?
Stormwater is all the water draining off your property - including from the roof, driveway and garden - and everything it carries with it such as sand, leaves, fertiliser, oil or litter.
Rainwater refers only to the rain that falls on the roof, which is usually cleaner.
Tanks connected into a home or to a retic system that's also supplied with mains water must meet regulations designed to protect the public supply from contamination. All of the components we supply are Watermark approved. We work closely with the builder's plumber on new homes and supply our own licensed trades on retrofits to ensure all regulations are met.
Legally, you can use tank water inside your home for anything you want. As a standard we follow Health Department guidance and suggest to clients not to plumb a tank into the kitchen supply if they have the choice of using mains water, but it's up to you whether you follow that advice. Many people prefer the taste of tank water.