What this tool does
Screens whether distributed subsurface basins can accept a short event without treating soil as unlimited storage.
When to use it
Use after a field infiltration assessment and after defining the actual number, area, effective depth and fill material of receiving basins.
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
The method is a transparent volume screen, not a soil, groundwater, setback or permit determination.
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
A 60 L event delivered at 90% to four 0.25 m² basins with 0.10 m effective depth and 30% void space has 30 L static capacity before entered-window infiltration.
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