High-Efficiency
Toilet Questions
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How did EPA set the specification for toilets?
The specification is based on the widely accepted Uniform
North American Requirements (UNAR) (PDF) (16 pp, 2.6MB, About
PDF)
for toilets and EPA industry and product research, in collaboration
with external stakeholders. The EPA specification sets the water
use level at 1.28 gallons per flush or less, includes design requirements,
and has a higher requirement for flush performance to ensure optimal
user satisfaction.
How was UNAR developed?
Uniform North American Requirements (UNAR) were developed by a collaboration
of water utilities to establish a standard for toilets in rebate
programs that would perform to customer expectations, save water
and maintain water savings over the long term.
What percentage of toilets currently qualify under the
specification?
The most recent list of toilets in the market shows approximately
249 models. There are currently more than 100 models, or about 40
percent, that might meet the high-efficiency toilet specification.
How does the specification ensure that these toilets will
perform as expected?
The specification includes a performance requirement. A collaboration
of U.S. and Canadian water utilities developed a flush performance
test protocol called the Maximum
Performance (MaP) test
to provide a uniform measure of toilet performance. Requirements
for this test protocol have been included in the high-efficiency
toilet specification.
How will EPA verify the testing?
Products will be independently certified by a third party to confirm
that the product meets EPA criteria for efficiency and performance.
Are toilets that meet the WaterSense specification more
expensive than other toilets?
No. MaP testing results have shown no correlation between price
and performance. Prices for toilets can range from less than $100
to more than $1,000. Much of the variability in price is due to
style, not functional design. Toilets that could potentially bear
the WaterSense label are currently in the low to middle range of
about $200. There is a lot of competitive pressure on manufacturers
to lower prices; therefore, it can be expected that as more toilets
become certified, the average price should fall.
Will the installation of high-efficiency
toilets lead to drainline and sewer problems due to the reduced
water flows?
Since the introduction of the 1.6 gallons per flush toilet in the
early 1990s, questions have been raised about whether sufficient
water exists to move solid wastes in the building drainlines and
in the municipal sewer system. To date, there has been no evidence
to show that waste transport problems occur because of the use of
the original low-flow toilets. The introduction of high-efficiency
toilets in the late 1990s precipitated the same concerns. As a result,
a collaboration of water utilities sponsored a full laboratory study
to address the issue. The drainline study, completed in 2004, concluded
that high-efficiency toilets flushing with as little as 1 gallon
provide sufficient water in residential and commercial applications
to move the waste from the fixtures to the sewer.
With regard to municipal sewer lines, the transport of waste has
not proven to be an issue of concern in those areas with a concentration
of high-efficiency toilets. Supplementary wastewater flows from
other end-uses are always sufficient to move solids through the
system. Furthermore, some wastewater utilities are co-funding and
sponsoring the toilet replacement programs and other water efficiency
initiatives of the water utilities for the very purpose of reducing
sewer flows to their treatment plants.
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