A water filter can be defined as any device which reduces impurities from a water supply. Within the broad category of water filters there are many different types of units.
Filters can be categorized and compared based upon the following criteria:
- Filter type
- What you are filtering for, such as by-products, taste or lead, for example
- Where the unit is installed or used, such as the countertop or under the sink
- The rated service life of the filter, usually expressed in months or gallons
Federal: There are no federal regulations regarding the design or effectiveness of water filters.
State: Four of the 50 U.S. states (California, Iowa, Massachusetts, and Wisconsin) have regulations and requirements for some types of water filters installed, sold or distributed in their state.
Federal: There are no federal standards regarding the design or effectiveness of water filters.
State: The four states with water filter requirements mandate that manufacturers making claims covered by their state statutes and regulations, submit data.
State: The frequency of testing varies.
Compliance & Enforcement
State: Compliance with state regulations is generally enforced through annual requirements to renew certifications/licenses, submission of testing data, and regulator follow-up on complaints or other information regarding changes in the manufacturer’s products or claims.
Federal: In contrast to bottled water, there are no federal regulations regarding the design or effectiveness of water treatment filters.
State: Because the source of the water may contain contaminants which the filter is not designed to reduce or contaminants in excess of the levels for which the unit was tested, state regulations are not intended to provide a guarantee that the final filtered water will meet all EPA safe drinking water act requirements.
California Department of Human Services, Health and Safety Code: Division 104, Part 12, Chpt 5, Article 3. 2003.
Iowa Department of Public Health, Iowa Administrative Code 641-Chapter 14: Residential Water Treatment.
Massachusetts Office of Consumer Affairs and Business Regulation. 248 CMR 10.00: Uniform State Plumbing Code.
NSF International, NSF/ANSI 42-2007a: Drinking Water Treatment Units-Aesthetic Effects. Ann Arbor: NSF International, 2007.
NSF International, NSF/ANSI 53-2007a: Drinking Water Treatment Units-Health Effects. Ann Arbor: NSF International, 2007.
Wisconsin Department of Commerce, Wisconsin Administrative Code: Chapter Comm 81: Definitions and Standards.
Wisconsin Department of Commerce, Wisconsin Administrative Code: Chapter Comm 84: Plumbing Products.