Fixture flow (gpm) & per-person gpd conventions
Two planning conventions drive well-pump and septic sizing: how much a fixture flows (gpm) at peak, and how much water a person uses per day (gpd). Both are labeled typicals, not fixed numbers — low-flow fixtures and habits change them. Use them in the required pump GPM, daily water use and daily wastewater flow tools.
| Fixture | Typical flow (planning) |
|---|---|
| Bathroom faucet | ~1.5 gpm |
| Kitchen faucet | ~2.2 gpm |
| Shower head | ~2.0 gpm |
| Toilet (per flush) | ~1.6 gal |
| Washing machine | ~3–5 gpm |
| Dishwasher | ~1–2 gpm |
Per-person household use is typically ~50–75 gpd (this site defaults to 75 gpd for design flow). Low-flow fixtures and habits change these — they are labeled planning conventions, not fixed values.