About Well Sizer

Well Sizer is an independent reference for people on private wells and septic systems. It sizes pressure tanks with Boyle's law, checks well pumps against a manufacturer's published selection chart, and quotes each state's own septic tank rule, with every figure linked to its source and the date it was checked.

It is run by a US-based software engineer as an independent project. It is not affiliated with Goulds, Xylem, Franklin Electric, AMTROL or any state agency, and does not sell pumps, tanks or installation.

How the site works

Pressure tank sizes come from Boyle's law and a motor maker's one-minute run-time rule, checked against Goulds' published tank tables. Pump picks come from Goulds' 10GS selection chart, household demand from Goulds' peak-demand table, and septic minimums from each state's own rule, quoted and linked. The methodology page lists every source and formula.

Corrections

If a figure is wrong or a source has changed, email hello@wellsizer.com with the page and a link. Corrections go into the data file and the check date updates with the next build.

Data version 2026-10-20.