Septic Tank Sizing Calculator
The Septic Tank Sizing Calculator finds the liquid volume and total tank size from occupancy, wastewater rate, and desludging interval. Example: for a 50-person residential septic tank at 150 L/person/day, Liquid volume = 22500 L, Daily flow = 7500 L/day, Sludge storage = 6000 L (per Philippine Plumbing Code §P-1101).
How it works
Computed from your inputs per Philippine Plumbing Code §P-1101.
Worked example (Plumbing & Pumps)
Inputs: a 50-person residential septic tank at 150 L/person/day.
| Result | Value |
|---|---|
| Liquid volume | 22500 L |
| Daily flow | 7500 L/day |
| Sludge storage | 6000 L |
Computed live by WorkHive's calculation engine; standard: Philippine Plumbing Code §P-1101.
How to use this calculator
- Enter the figures for the duty you are sizing: the worked example below uses a 50-person residential septic tank at 150 L/person/day.
- The calculator returns Liquid volume, Daily flow, Sludge storage, computed per Philippine Plumbing Code §P-1101.
- 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 septic tank sizing calculator?
The Septic Tank Sizing Calculator is a free online tool that computes finds the liquid volume and total tank size from occupancy, wastewater rate, and desludging interval. 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 Philippine Plumbing Code §P-1101. 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 Septic Tank Sizing Calculator in WorkHive: free, no sign-up needed for the calculators.