The WQA Sustainability Mark is awarded to those drinking water treatment products which have been WQA certified in accordance with "WQA S-803: Sustainable Drinking Water Treatment Systems,” as a service to the industry and consumers.

This certification means that production of the listed drinking water treatment systems has been audited and evaluated by the Water Quality Association, and was found to have met the voluntary industry standard, WQA S-803. As a prerequisite, the listed product must also first be certified to the applicable NSF/ANSI or WQA safety/performance standard (e.g. NSF/ANSI 42). In addition, the corporate management system as well as the facilities where the product is manufactured must pass evaluation as conforming to the prerequisite standard "WQA S-801: Sustainable Management."

The WQA is a not-for-profit international association of manufacturers, distributors, and dealers of water treatment systems for household, commercial, municipal and industrial applications. WQA's on-line directory of certified products is continuously updated to identify those water treatment products that have passed rigorous industry standards to become certified by the Water Quality Association.