What this tool does
Builds a source-by-source water balance and applies one explicit capture factor instead of hiding household defaults.
When to use it
Use before choosing an irrigation area, outlet layout or treatment system. Measure actual fixture flow, appliance volume and cycles where possible.
Inputs and supported units
Each labelled field explains the quantity it expects. Unit-system changes convert existing numeric entries once and keep calculations on a single SI internal basis. Supported shared units include L/min and GPM, metres and feet, kPa and psi, millimetres and inches, kW and hp, and °C and °F as relevant.
Calculation or decision method
Toilets are excluded. Kitchen sources are not assumed acceptable because definitions and risk controls vary by jurisdiction.
How to interpret the result
Read the primary result with the supporting breakdown and warning. A plausible number is not evidence that every input, operating case or design constraint has been included.
Worked example
Two people using 8 L/min showers for six minutes each, four 55 L laundry loads per week and 8 L/person/day at bathroom basins generate about 143.4 L/day before a capture factor.
Assumptions
Entered fixture, event, climate, soil and tariff values describe the planning case; volumes are kept on an SI internal basis.
Limitations
The result is a preliminary quantity or cost screen. It does not approve a source, end use, plumbing connection, treatment process, setback, storage time or irrigation method.
Sources
- San Francisco Public Utilities Commission — Graywater Design Manual
- Washington State Department of Health — Greywater Reuse
- U.S. EPA WaterSense — Water Budget Tool
- Australian Government — Australian Guidelines for Water Recycling