# 10 CFR § 429.30 - Water closets.

§ 429.30 Water closets.

(a) Sampling plan for selection of units for testing.

(1) The requirements of § 429.11 are applicable to water closets; and

(2) For each basic model of water closet, a sample of sufficient size shall be randomly selected and tested to ensure that any represented value of water consumption of a basic model for which consumers favor lower values shall be greater than or equal to the higher of:

(i) The mean of the sample, where:

$\begin{array}{c}\stackrel{—}{x}=\frac{1}{n}\sum _{i=1}^{n}{x}_{i}\\ \text{and,}\stackrel{—}{x}\phantom{\rule{0ex}{0ex}}\text{is the sample mean; n is the number of samples; and}\phantom{\rule{0ex}{0ex}}{x}_{i}\phantom{\rule{0ex}{0ex}}\text{is the}\phantom{\rule{0ex}{0ex}}{i}^{\mathrm{th}}\phantom{\rule{0ex}{0ex}}\text{sample;}\end{array}$

Or,

(ii) The upper 90 percent confidence limit (UCL) of the true mean divided by 1.1, where:

$\begin{array}{c}UCL=\stackrel{—}{x}+{t}_{.90}\left(\frac{s}{\sqrt{n}}\right)\\ \mathrm{And}\phantom{\rule{0ex}{0ex}}\stackrel{—}{x}\phantom{\rule{0ex}{0ex}}\text{is the sample mean; s is the sample standard deviation; n is the number of}\phantom{\rule{0ex}{0ex}}\\ \text{samples; and}\phantom{\rule{0ex}{0ex}}{t}_{0.90}\phantom{\rule{0ex}{0ex}}\text{is the t statistic for a 90% one-tailed confidence interval with n-1}\\ \text{degrees of freedom (from Appendix A).}\end{array}$

(b) Certification reports.

(1) The requirements of § 429.12 are applicable to water closets; and

(2) Pursuant to § 429.12(b)(13), a certification report shall include the following public product-specific information: The maximum water use in gallons per flush (gpf), rounded to the nearest 0.01 gallon. For dual-flush water closets, the maximum water use to be reported is the flush volume observed when tested in the full-flush mode.

[76 FR 12451, Mar. 7, 2011; 76 FR 24771, May 2, 2011, as amended at 78 FR 62986, Oct. 23, 2013]