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Water Closets (Flush Toilets)

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The Department of Energy (DOE) has regulated the energy efficiency level of water closets (flush toilets) since 1992. Water closets (flush toilets) dispose of human waste by using water to flush it through a drainpipe to another location.

The current standard will result in approximately $132.2 billion in savings for products shipped from 2007-2026.

The standards and test procedures for this product are related to rulemaking for plumbing products test procedure.

Recent Updates | Standards | Test Procedures | Waiver, Exception, and Exemption Information | Statutory Authority | Historical Information | Contact Information

Recent Updates

DOE published a final rule regarding test procedures for showerheads, faucets, water closets, urinals, and commercial prerinse spray valves. 78 FR 62970 (October 23, 2013). For more information, please see the rulemaking page.

Standards for Water Closets (Flush Toilets)

DOE published a notice of proposed rulemaking regarding updating test procedures for water closets (flush toilets). 77 FR 31742 (May 30, 2012). The comment period closed August 13, 2012.

Current Standard

Water closets (flush toilets) manufactured and distributed in commerce, as defined by 42 U.S.C. 6291 (16), on or after September 14, 1998 must meet the energy conservation standards specified in the Code of Federal Regulations, 10 CFR Part 430.32(q).

WATER CLOSET TYPE Maximum flush rate (gpf (Lpf))
Gravity tank-type toilets 1.6 gpf (6.0 Lpf)
Flushometer tank toilets 1.6 gpf (6.0 Lpf)
Flushometer valve toilets 1.6 gpf (6.0 Lpf)
Electromechanical hydraulic toilets 1.6 gpf (6.0 Lpf)
Blowout toilets 3.5 gpf (13.2 Lpf)

For further guidance or to submit questions related to the implementation of this standard, visit the Guidance and Frequently Asked Questions page.

Test Procedure for Water Closets (Flush Toilets)

Current Test Procedure

To determine compliance with DOE standards, manufacturers must follow the test procedures specified at 10 CFR Part 430, Subpart B, Appendix T for water closets (flush toilets) manufactured or distributed into commerce on or after May 19, 1981.

For further guidance or to submit questions related to the implementation of this test procedure, visit the Guidance and Frequently Asked Questions page.

Waivers, Exceptions, and Exemptions


Test procedure waivers have not been issued for water closets. 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.

State Exemptions to Federal Preemption

DOE issued a final rule on December 22, 2010 that waived federal preemption of any state regulation concerning the water use or water efficiency of faucets, showerheads, water closets and urinals, if such state regulation is more stringent than the federal regulation for the same product. This action was taken in order to comply with a provision of the Energy Policy and Conservation Act, which requires that DOE waive federal preemption for these products if the corresponding ANSI/ASME water conservation standards for them have not been changed after a period of five consecutive years. (42 U.S.C. 6295(j)(3)(C) and 6295(k)(3)(C))

Statutory Authority

The current energy conservation standards for water closets are mandated by Part A, the ‘‘Energy Conservation Program for Consumer Products Other Than Automobiles’’ of Title III of the Energy Policy and Conservation Act, as amended. (42 U.S.C. 6291–6309) Water closets are treated as a covered product under Part A. (42 U.S.C. 6295(k))

Historical Information

Congress established the standards for showerheads, faucets, water closets, and urinals as part of the Energy Policy Act of 1992, which amended the existing Energy Policy and Conservation Act of 1975 (EPCA). Congress based the conservation standards for these products, and the test procedures that would be required for rating them, on the existing American Society of Mechanical Engineers/American National Standards Institute (ASME/ANSI) standards for each respective group of products.

For faucets and showerheads, EPCA states that the conservation standards shall be those of ASME/ANSI A112.18.1M-1989 and that for water closets and urinals the standards shall be those of ASME/ANSI A112.19.6-1990, both of which DOE subsequently adopted into the Code of Federal Regulations.

On March 18, 1998, DOE issued a final rule that updated the test procedures for these products by adopting more recent versions of both ASME/ANSI standards, which are the versions in use by DOE today. They are A112.18.1M-1996 for faucets and showerheads, and A112.19.6-1995 for water closets and urinals. The water conservation standards in the revised ASME/ANSI standards remained the same.

Helpful Links and Contact Information

Helpful Links

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Contact information

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