SUPADIVERTA - syphonic rainwater diverter

WATER TANKS

OVERFLOW PIPE WARNING

AQUATREK has seen tanks harvesting several downpipes with each diverted to the tanks inlet strainer.

Gutter and downpipe size requirements are calculated using a formula based on a regions 1:20 Average Recurrence Interval (ARI) as required by the Building Code Australia (BCA) and detailed in AS/NZS3500. Calculations are based on a 5 minute rainfall intensity.

In the above situation, the tank’s overflow is expected to handle the inflow volume of several same sized downpipes during a storm event but a tank's overflow cannot drain more water than the maximum roof area that the same sized downpipe can harvest.

The diverting of additional downpipes to a tank fitted with a single same size overflow pipe connected to stormwater will contravene plumbing regulations that generally state the downpipe volume must not exceed the tank’s overflow capacity. Overflowing tanks can cause property damage and annoyance to neighbours.

Incredibly, some councils have overridden the requirement for tanks to be fitted with an adequate overflow provision. AQUATREK strongly suggests that householders exercise their best judgment in these situations.

The harvesting of additional downpipes by SUPADIVERTA through a tanks bottom inlet/outlet DOES NOT affect overflow capacity provided the static head is below the level of the tank’s overflow pipe. See harvest more water.

HANDY HINT IF FITTING AN OVERFLOW PIPE

A thin organic scum often develops on the surface of tank water. When the tank fills, the scum passes through the overflow mesh to storm water but often leaves deposits on the mesh. The mesh is often difficult to inspect and clean and could restrict or block the flow of water. AQUATREK strongly recommends fitting a FLAP VALVE to the tank’s overflow in place of the fixed mesh outlet to safeguard against this possibility.