Septic Tank Sizing Calculator
Static · formula-only · worked example computed when this page was built · no live data
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, at 3 days retention, 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. Anything the worked example does not state uses this calculator's standard default; the interactive version shows every input and lets you change it.
Worked example (Plumbing & Pumps)
Inputs: a 50-person residential septic tank at 150 L/person/day, at 3 days retention.
| Result | Value |
|---|---|
| Liquid volume | 22500 L |
| Daily flow | 7500 L/day |
| Sludge storage | 6000 L |
Computed by WorkHive's calculation engine when this page was built; standard: Philippine Plumbing Code §P-1101.
How to use this calculator
- Read the worked example. It uses a 50-person residential septic tank at 150 L/person/day, at 3 days retention and shows every number in the method.
- Follow the formula with your own figures: it returns Liquid volume, Daily flow, Sludge storage, computed per Philippine Plumbing Code §P-1101.
- To compute interactively, open the Septic Tank Sizing Calculator inside WorkHive's free Engineering Design suite (link below). It runs the same method with your inputs.
FAQ
What is a septic tank sizing calculator?
The Septic Tank Sizing Calculator is a free online tool that 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 is free: this worked example is open to everyone, and the interactive calculator runs inside the free Engineering Design suite after a free sign-up (your work is saved to your account). 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, and a free sign-up saves your calculations, BOMs and scope-of-works to your account.