Water Audit
Assess the water flows on your site — how much falls, where it goes, how much you use, and where the opportunities are for harvesting, storage, and reuse. This is the foundation of any water-smart design.
Version History
Version 1.0 Current
Effective: 2026-03-30Initial version
Procedure Details
No hazards. Take care near waterways, dams, or steep slopes during site observation.
You will need:
- Local rainfall data (Bureau of Meteorology or weather records)
- Measuring tape
- Calculator
- Site map or sketch
- Water bills (if available) for usage data
Procedure Steps (Version 1.0)
Research your annual rainfall using Bureau of Meteorology or local weather station data. Record in mm per year.
Measure or estimate the total roof catchment area of your buildings in square metres.
Calculate potential roof harvest: catchment area (m²) × annual rainfall (mm) × 0.8 (efficiency) = litres per year.
Estimate your daily water usage from bills or by monitoring for a week. Include garden, household, and animals.
Walk your site after rain. Observe where water pools, flows, and exits the property. Mark these on your site map.
Identify greywater sources (laundry, shower, kitchen) and estimate daily volume.
Assess current storage: tank capacity, dam volume, soil water-holding capacity.
Calculate the gap: annual demand minus annual supply. This is what your design must address.
Identify 3 opportunities for improvement: additional storage, greywater reuse, swales, rain gardens, or reduced demand.
Record all findings as observations. Photograph key water flows and problem areas.