Calculated result
Engineering evaluation Calculation complete—verify project criteria Usable treated-water volume (V_u) 450 gal/day
Demand offset (O_d) 75 %
Surplus or deficit (M_v) -150 gal/day Engineering interpretation The entered collection and treatment recovery provide 450 gal/day, offsetting 75% of stated demand.
Important limitations Daily volume balance only. Storage chronology, first flush, seasonal variability, treatment process, cross-connection control, water quality, public-health requirements, overflow, makeup, and code approval are omitted. Copy results Open printable PDF Download PDF
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Understand the calculation—not just the answer 2026-08-07 · Free Library Equations & method Engineering guide Reference data & sources
Governing relationships V_u=F_r V_c
O_d=100min(V_u,V_d)/V_d
M_v=V_u−V_d
Current substitution V_u=0.9×500=450; O_d=75%; M_v=-150.
Calculation sequence
Step-by-step method Confirm the input boundary, formula symbols, and unit system. Apply the displayed equation to the user-entered values. Compare the screening result with project criteria, manufacturer data, and applicable standards. Equation legend
Inputs and calculated quantities
V_c Collected greywater volume — gal/day or L/day
F_r Treatment recovery fraction — 0–1
V_d Nonpotable daily demand — gal/day or L/day
V_u Usable treated-water volume — gal/day
O_d Demand offset — %
M_v Surplus or deficit — gal/day Applications
How this calculation is used Building design Screen a documented plumbing-system relationship without embedding a protected code table.
Construction Check submitted or field values against the same transparent calculation basis.
Commissioning Reconcile measured and scheduled conditions before professional disposition.
Quality controls
Assumptions and limitations Assumptions User-entered values describe one documented system boundary and operating condition. All inputs use the displayed formula symbols and a consistent unit system. Limitations This transparent screen does not establish code compliance, equipment selection, or acceptance. Project criteria, manufacturer data, adopted codes, uncertainty, and professional judgment remain controlling. Field use
Verification procedure Confirm the system boundary and source of each input. Record representative values in the displayed units. Review the result against project criteria, manufacturer data, and applicable standards. Common engineering mistakes Mixing values from different pressure, temperature, flow, or time bases. Treating a screening result as a hidden design criterion or automatic pass/fail decision. Technical basis
References and source standards Need project-specific support?
Work with SVE Group Use this free tool for preliminary evaluation and field support. For project requirements, system analysis, commissioning, or engineering services, connect with SVE Group.
Visit SVE Group Contact the firm Engineering calculation disclaimer These engineering tools are provided for educational, preliminary evaluation, field verification, and commissioning support. Results depend on the accuracy of user-entered information and the assumptions stated for each calculation. Every colored status and comparison is a screening indicator only; project criteria, contract requirements, applicable codes, manufacturer instructions, measurement uncertainty, and authorized engineering judgment govern. The tools do not replace project-specific engineering analysis or the judgment of a licensed professional engineer.
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