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Water Closets

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The Energy Policy and Conservation Act, as amended, 42 U.S.C. 6291–6309 (EPCA) establishes energy conservation or water use standards and test procedures for certain consumer products, including water closets. Title 10 of the Code of Federal Regulations, Part 430 (10 CFR 430), defines the term “water closet” to mean a plumbing fixture that has a water-containing receptor which receives liquid and solid body waste, and upon actuation, conveys the waste through and exposed integral trap seal into a gravity drainage system, except such term does not include fixtures designed for installation in prisons. (10 CFR 430.2)  The Department of Energy (DOE) last amended the test procedures for water closets on September 30, 2013.  Under the provisions of 42 U.S.C. 6295(k)(3), the water use standards for water closets have not been amended.

Current Standard | Current Test Procedure | Ongoing Rulemaking for Standards | Ongoing Rulemaking for Test Procedure | Helpful Links

Recent and Ongoing Activities

DOE has published a Federal Register final rule pertaining to test procedures for water closets and urinals. This final rule amends the test procedures for water closets and urinals to reference the most recent update to the relevant industry standard, American Society of Mechanical Engineers (ASME) Standard A112.19.2-2018. In this final rule, DOE is also amending certain definitions and adding definitions for certain terms that are currently used in the Federal test procedures but are not defined.

  • The effective date of this rule is April 22, 2022.
  • The final rule changes will be mandatory for product testing September 19, 2022.
  • The incorporation by reference of certain material listed in this rule is approved by the Director of the Federal Register April 22, 2022.

For the latest information on the planned timing of future DOE regulatory milestones, see the current Office of Management and Budget Unified Agenda of Regulatory and Deregulatory Actions. All planned dates are preliminary and subject to change.


The Energy Policy Act of 1992 amended EPCA to add water conservation standards for water closets, based on the flush volume requirements contained in American Society of Mechanical Engineers (ASME)/American National Standards Institute (ANSI) Standard A112.19.6-1990, which are codified under Title 42 of the U.S. Code (42 U.S.C.) section 6295(k).  Under 42 U.S.C. 6295(k)(3), if the flush volume requirements contained in ASME/ANSI Standard A112.19.6 are amended to improve efficiency of water use, the Secretary of Energy shall consider establishing an amended uniform national standard at the level specified in the amended ASME/ANSI Standard.  To date, ASME has not updated the flush volume requirements for water closets.

Public Meeting Information:

There is no public meeting scheduled at this time.

Submitting Public Comments

The comment period is closed.

Test Procedure

Final Rule 
  • Federal Register, 87FR16375 (March 23, 2022)
Notice of Proposed Rulemaking
  • Federal Register, 86FR27281 (May 20, 2021)
Notice of Data Collection
  • Federal Register, 84FR37970 (August 5, 2019)

The water closet test procedure rulemaking docket EERE-2011-BT-TP-0061 contains all pertinent notices, public comments, public meeting transcripts, and supporting documents.

Public Meeting Information

There is no public meeting scheduled at this time.

Submitting Public Comments

Comment period is closed.

Current Standard

The flush rate of a water closet, manufactured and distributed in commerce, as defined by 42 U.S.C. 6291(10) and (16) respectively, must be not greater than the maximum water use standards under 10 CFR 430.32(q).

Current Test Procedure

To determine whether a water closet is in compliance with the water consumption standards under 10 CFR 430(q), a manufacturer must measure the maximum flush volume in accordance with 10 CFR 430, Appendix T to Subpart B.

Helpful Links


DOE has established regulations on certification, compliance, and enforcement in 10 CFR Part 429.  These regulations cover statistical sampling plans, certified ratings, certification reports, record retention, and enforcement.  More information about compliance and enforcement is available on DOE's Implementation webpage.


For information on current test procedure waivers, see DOE’s Waivers webpage.

For information about obtaining test procedure waivers, see 10 CFR 430.27.


DOE's Office of Hearings and Appeals has not authorized exception relief for water closets.

For information about obtaining exception relief, see 10 CFR part 1003.

Guidance and Frequently Asked Questions

For information on further guidance and answers to Frequently Asked Questions on all covered products, see DOE’s Further Guidance database.

State Exemptions to Federal Pre-emption

A State may petition DOE for exemption from preemption of a Federal water conservation standard in certain cases of unusual or compelling State or local water interests.  A State may also petition DOE to withdraw such exemption. See 10 CFR part 430, subpart D.  DOE has not exempted any State from this water conservation standard.

On December 22, 2010, DOE published in the Federal Register a final rule to waive the general rule of Federal preemption for water use standards, under 42 U.S.C. 6297(c), with respect to any State regulation concerning water closets if such State regulation is (1) more stringent than Federal regulation concerning the water use or water efficiency for that same type or class of product, and (2) applicable to any sale or installation of all products in that particular type or class.  75 FR 80289.

Small Business Exemptions

Any manufacturer of a covered product with annual gross revenues that do not exceed $8,000,000 from all its operations and meets certain other conditions may apply for an exemption to the energy conservation standard. For details, see 10 CFR part 430, subpart E


DOE supports the testing and verification of ENERGY STAR® products in close collaboration with the Environmental Protection Agency.

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