THE BIGGEST REDUC TION in per capita
water use between the two studies
was measured in the clothes washer
category. Starting in the mid-1990s,
efficiency improvements dramatically
reduced water usage, from an average
volume of 41 gallons per load (gpl)
(REU1999) to 31 gpl (REU2016). Per capita use decreased 36%, from 15.0 gpcd
(REU1999) to 9.6 gpcd (REU2016).
The flush volume of toilets has
decreased 29%, from 3.65 gallons
per flush (gpf) (REU1999) to 2.6 gpf
(REU2016). Toilet flushing frequency
has remained the same—5.0 flushes
per person per day. In REU1999, just
8.5% of toilet flushes were 2.0 gpf or
less. In REU2016, 37% of toilet flushes
were 2.0 gpf or less.
Efficiency criteria include: clothes washers ≤30 gal/load, toilets ≤2.2 gal/flush, showers ≤2.5 gal/minute.
Figure 4. Percent of homes meeting efficiency criteria, REU1999 and REU2016
An automatic dishwasher was present in 84% of the end use study homes in
REU2016. The average water
volume per dishwasher load
decreased 39%, from 10.0
gpl (REU1999) to 6.1 gpl
children (aged 12 and under) increased
out and are replaced. The current average daily indoor per household use of
138 gphd could decrease to 110 gphd with
full adoption of water-efficient fixtures.
Per capita use of 58.6 gpcd is expected to
reduce to 36.7 gpcd in the coming years.
(REU2016). A comparison
of households showed
that if a house lacked a
dishwasher, faucet use did
not increase, which would
normally be supposed.
Regardless of the presence
of a dishwasher, faucet use
averaged 26 gphd.
use are largely
due to more
and are not the
result of either
The average daily per
capita leakage decreased 17%, from 9.5
gpcd (REU1999) to 7.9 gpcd (REU2016).
Thirty-two percent of homes had higher
leakage rates, as high as 600 gallons per
household per day.
REU2016 shows minimal change in
showering patterns. The average duration held steady at 7.8 minutes per shower.
The flow rate decreased just 0.1 gallon
per minute. The average faucet use per
household and per capita did not change
at a statistically significant level from
REU1999 to REU2016. Bathtubs showed a
small increase, from 1.2 gpcd (REU1999)
to 1.5 gpcd (REU2016). The presence of
MORE EFFICIENT APPLI-
ANCES and fixtures have
contributed to significant
reductions in residential
indoor water use, but there
remains much potential
for additional savings. In
REU2016, more than half of
residences did not meet the
study’s efficiency criteria for
ers and toilets, and 20% did
not meet those standards
for showers (Figure 4). In
addition, households that
currently over-irrigate could
change their habits and
substantially reduce their
There are a number of common strategies to maximize outdoor efficiency.
Utilities should encourage excess irrigators to be more water-efficient. Deficit
irrigators (those using less than the theoretical irrigation requirement) should be
prevented from increasing their irrigation
in the future.
Even without a concerted effort on the part of
homeowners to switch to
more efficient appliances
and fixtures, reductions are
anticipated as old toilets
and clothes washers wear
THE 23 utilities
studied in this
a time and place
snapshot of how
water is used in
homes in North
on a statistically
tive sample of
About This Study
RANDOM SAMPLES OF
representative single-family customers were
the center of the research.
The study collected highly
detailed information from
2010 to 2013 on water
use, demographics, and
the homes’ landscapes.
REU2016 followed the same
basic research approach
as REU1999, with some
notable additions. The new
study included more varied
site locations, collection