| #D001 | | NSF | NSF International | high |
| #D002 | | ANSI | American National Standards Institute | high |
| #D003 | | Treatment additives | used to make the water safer (e.g., disinfectants to inactivate microorganisms) | high |
| #D004 | | drinking water system components | used to carry the water to the consumer (including pipes and fittings) | high |
| #D005 | | drinking water treatment devices | used to treat the water, often at the point of consumption (e.g., pitcher-type water filters, reverse osmosis units) | high |
| #D006 | | Certification organizations | provide assurance that a product or material is safe by testing them to ensure they meet the applicable standards | high |
| #D007 | | Health-based standards | designed to safeguard drinking water by helping to ensure the material safety and performance of products that come into contact with drinking water | high |
| #D008 | | plumbing standards | focus on installation requirements | high |