Free Sewage Flow Rate Calculator
Estimate daily sewage discharge from a building based on occupancy and per-capita wastewater generation.
people
gal/day
Average Daily Flow
4,000 gal/day
Peak Hourly Flow417 gal/hr
Peak Minute Flow6.9 GPM
Average Daily Flow vs Number of Occupants
Sewage Flow Estimation
Average Daily Flow = Occupants x Per Capita GPD
Peak Flow = Average / 24 x Peak Factor
Residential per-capita wastewater is typically 60 to 100 gallons per day. The peak-hour factor (2 to 4 for residential, up to 5 for commercial) accounts for the morning and evening surges.
Example Calculation
50 occupants, 80 gal/day each, peak factor 2.5.
- 01Avg daily = 50 x 80 = 4,000 gal/day
- 02Avg hourly = 4,000 / 24 = 167 gal/hr
- 03Peak hourly = 167 x 2.5 = 417 gal/hr
- 04Peak GPM = 417 / 60 = 6.9 GPM
Frequently Asked Questions
Learn More
How to Calculate Concrete Needed for Any Project
Learn how to calculate the exact amount of concrete needed for slabs, footings, columns, and other projects. Covers volume formulas, waste factors, and ordering tips.