Tank bling
This is an excerpt from an article in Sanctuary magazine issue 5.
So you have chosen a tank that suits your needs and are ready to install. But before you call the plumber have a think about any other rainwater tank accessories you may need to keep your water clean and healthy. Prevention is better than cure and poorly maintained roofing or guttering, overhanging trees, birds, possums, and air pollution can all affect water quality. There are a number of ways you can minimise the amount of contaminants that enter the tank. Other devices are also available to help you manage your rainwater.
Gutters
Gutter guards or special gutters with filters can be used to prevent leaves and debris entering the guttering. The need for these is dependent on the extent to which the roof of your house has overhanging or nearby trees. Leaves can block the guttering causing the rainwater to overflow rather than go into the tank. Blockages can also cause water to pool in the gutter, providing habitat for mosquitos. Leaves that accumulate in the gutters can also start to break down, causing leaching and discolouring of the water.
Choose gutter guards that install in line with the roof gradient, rather than those that create a curved barrier over the gutter that may collect leaves on the upper side. Alternatively, there is guttering available that has two layers, with filters mounted in the top layer to exclude leaves and debris but which allow water to flow into the bottom layer. The top layer of this guttering is shallower than standard guttering, with the intention that it is self cleaning as the wind blows leaves out of it. This happens to some extent, but it will still require brushing periodically depending on the location.
Leaf diverters
Leaf diverters can also be used to screen leaves and debris from entering the downpipes and tanks. These are mounted on the downpipe and typically consist of a mesh screen angled to deflect leaves, but that allows water to flow through into the downpipe. If you are already using gutter guards or guttering that screens leaves then these should not be needed. They are an alternative to gutter guards for stopping leaves entering the downpipes, but they don’t stop leaves accumulating in the gutters.
First rain diverters
First rain diverters are used to divert the first bit of rain—20 to 25 litres for an average roof catchment—away from the rainwater tank along with any accumulated contaminants from the roof or guttering. Health authorities recommend these as an additional barrier to reduce contamination rather than a reason to avoid the maintenance of keeping the roof and gutters clean.
Plumbing and tank suppliers sell a range of first rain diverters. Simple downpipe first rain diverters consist of a vertical pipe with a ball inside. As the pipe fills, the ball floats up and the rain then flows into the tank. The first bit of rain is below the ball and this then drips out to the garden over a period of time, so that next time it rains the diverter is ready to accept more water. The base of the diverter needs to be removed periodically to flush out any accumulated sediment or debris.
