Domestic Water Demand Calculator
The Domestic Water Demand Calculator finds peak water flow, tank size, and booster need from a building's water-supply fixture units. Example: for a 3-floor building (50 persons) with 10 flush-valve WCs, 8 lavatories, and 4 showers, Water fixture units = 124 WSFU, Peak flow = 275.9 L/min, Storage tank = 1 m³ (per PSME Code | ASPE Vol.2 | PNS 65 | ASHRAE 2021 Ch.50).
How it works
Computed from your inputs per PSME Code | ASPE Vol.2 | PNS 65 | ASHRAE 2021 Ch.50.
Worked example (Plumbing & Pumps)
Inputs: a 3-floor building (50 persons) with 10 flush-valve WCs, 8 lavatories, and 4 showers.
| Result | Value |
|---|---|
| Water fixture units | 124 WSFU |
| Peak flow | 275.9 L/min |
| Storage tank | 1 m³ |
Computed live by WorkHive's calculation engine; standard: PSME Code | ASPE Vol.2 | PNS 65 | ASHRAE 2021 Ch.50.
How to use this calculator
- Enter the figures for the duty you are sizing: the worked example below uses a 3-floor building (50 persons) with 10 flush-valve WCs, 8 lavatories, and 4 showers.
- The calculator returns Water fixture units, Peak flow, Storage tank, computed per PSME Code | Hunter's Curve.
- Check the worked example to confirm the method matches how you would do it by hand, then run your own numbers in the interactive tool.
FAQ
What is a domestic water demand calculator fixture units?
The Domestic Water Demand Calculator is a free online tool that computes finds peak water flow, tank size, and booster need from a building's water-supply fixture units. It shows the formula and a fully worked example so you can check the method, not just the number.
How is it calculated?
The result is computed from your inputs following PSME Code | Hunter's Curve. The worked example on this page shows a real computation with real numbers.
Is the calculator free?
Yes. WorkHive's engineering calculators are free to use, no sign-up needed for the tools. WorkHive is a free, offline-first maintenance platform built for Philippine industrial plants.
Run it on your own numbers
Open the interactive Domestic Water Demand Calculator in WorkHive: free, no sign-up needed for the calculators.