Rainwater Reuse Sizing — New Dwelling, City of Sydney

Council —City of Sydney

Development — Residential — Single dwelling

Services — Stormwater Management Plan· Water Sensitive Urban Design · Hydrology Assessment

Year — 2022

Outcome — Approved

Background

The client needed a stormwater management plan for construction certificate submission, and separately wanted the rainwater tank sized properly. Neither council nor BASIX imposed a rainwater requirement on this site, so the tank was the client's own decision — which made getting the size right a question of value rather than compliance.

The problem

Estimating the tank volume that would actually serve the development, rather than defaulting to a standard size.

Our solution

We gathered local precipitation data, roof catchment area and estimated daily demand, then ran water balance calculations to model how often the tank would run dry and how often it would overflow across a typical year. That gave a defensible tank size matched to the household's actual usage.

Was it approved? Yes.

Below ground rainwater tank detail