The Wisconsin Department of Commerce approved a system for sizing point-of-entry water treatment devices, such as softeners and iron filters, that is an alternative to current sizing requirements contained in the Wisconsin Uniform Plumbing Code.

The approval is based on data reported in a study commissioned by the Water Quality Association, titled "Analysis of Indoor Peak Demands in 60 Selected Single-Family Homes." Aquacraft Inc., a water engineering and management firm, conducted the study.

The current state plumbing code requires plumbers and installers to size POE water treatment equipment using traditional fixture unit value flow-rate calculations. When code design flow rates are too high, oversized POE water treatment devices, which are inefficient and more expensive, would be required by code.