How to Quantify Potential Supply from Alternative Sources
Rainwater Harvesting
The amount of usable water that can be supplied from rainwater harvesting depends on:
- amount of rainfall
- size and type of roof
- size of the rainwater storage tank
An estimate of the potential rainwater supply can be obtained using the following calculator.
100 m2 of roof can supply 2400 litres of water from a 1-inch rain event.
A more precise estimate can be made by multiplying the roof area, mean rainfall for the site (over the past 10 years) and the run-off coefficient (typically 0.8-0.9 for metal roofs).
Greywater Recycling
The amount of greywater available for use depends on how much water is used in greywater-producing fixtures including:
- Showers
- Bathroom Sinks
- Laundry
Wineries without residential or guest accommodations are unlikely to generate significant amounts of domestic greywater for recycling. A rough estimate of the available greywater supply can be obtained using the following calculator.
Wineries that are adding guest accommodations should consider greywater recycling at the planning and design stage. Adding plumbing to integrate greywater recycling during construction requires minimal additional cost compared to retrofitting plumbing in an existing building.
Wineries can obtain a more detailed estimate of greywater availability by working with a greywater recycling expert.
