Commercial water treatment equipment is used in point-of-entry (POE) and point-of-use (POU) applications connected to building plumbing to improve the water quality characteristics of potable water. ASSE 1087 includes testing requirements for components and complete systems. Electrical compliance is not covered by the standard.

Plumbed water treatment units include any device or component, point-of-entry and point-of-use that is used in building to improve the quality of the water. ASSE 1087 covers all water treatment products that are connected to the building's plumbing system for potable water. This standard is not intended to cover water treatment products used for process water or wastewater applications. Examples of water treatment equipment include: deionizers, filters, softeners, reverse osmosis assemblies, ultraviolet systems, ozone systems, and distillers.

The contaminant reduction and structural integrity requirements for commercial modular systems are covered by NSF/ANSI 42 and NSF/ANSI 53 as appropriate. This standard covers the other plumbing aspects that are not otherwise addressed in those and other standards.