Wells & water/ CALCULATOR
Hot-water wait time and wasted water
Estimate how long cooled water must run before hot water arrives, plus the daily and annual water sent to the drain.
Use the actual internal bore of the hot-water pipe, not its nominal or outside size.
Measure the developed route, including vertical and horizontal sections.
Measure with a container and timer at the usual tap setting.
Count only draws after the branch has cooled; closely spaced uses may share one purge.
Use fewer days for a seasonal or intermittently occupied home.
Add both volumetric charges when wastewater is billed from metered water use.
Water held in the branch
2.41 L
Estimated wait from a cold branch
24.1 s
Water sent to drain per occupied day
14.5 L/day
Annual water sent to drain
5.28 m³/year
Annual water and wastewater cost
13.21 currency/year
A full straight circular pipe of one internal diameter, constant waiting flow and one complete purge for every counted cold-start draw. Fittings, mixed diameters, branch dead legs, recirculation, the volume inside fixtures and the user’s chosen acceptable arrival temperature are excluded.