Department of Building Construction Management
Impact of ULF and H-E toilets on Drainline Carry
Veritec Test
This test created, “more difficult than average” conditions for
testing. It used a 4” clear plastic pipe rather than 3” at a 1% grade.
The clear pipe was chosen to allow the distance sample’s travel to
be viewed. A minimum of 4 meters (approx. 13 feet ) was
required. Three styles of H-E toilets were tested: 1.2 gpf gravity
washdown, 1.28 gpf gravity siphonic and 1.0 gpf pressure assist.
Testing was run with no supplemental flows from other waste
water producing devices and ran a ratio of liquid to solid flushes
of 1:1 rather than the average range of 3:1 to 5:1. The samples
used were 350g samples of soy paste and toilet paper. To create
the floating samples powdered styrofoam was mixed into the soy
paste. The toilet paper sample was four balls of six sheets each.
The results are shown in the chart.
Additional Facts
Caroma
Pressure assisted toilets are less likely to clog than 3.5
gpf toilets.
The majority of 1.6 gpf toilets work well and owners
claim to be satisfied or very satisfied with performance
90% of owners in San Diego, CA
95% of owners in Austin, TX
91 % of owners in Tampa, Fl
350g Floating Waste
1.20-gallon
1-gallon Pressure- 1.28-gallon Gravity
Washdown
Assist
1st
5.8 m (19.2
1st 2.0 m (6.4 ft) 1st
4.5 m (14.8
Flush
ft)
Flush
Flush
ft)
2nd 9.0 m (29.5
2nd 4.9 m (16.1
2nd 9.0 m (29.5
Flush
ft)
Flush
ft)
Flush
ft)
the key requirement between the WC and drain
line is to fully discharge the waste from the
bowl outlet using initial part of the flush and
then to achieve steady flow conditions within a
minimum distance within the drain line system
in order for the waste to effectively clear the
drain line.
Several of the test locations had situations of “above
average” difficulty due to the length of the minimum grade
line, varying grades along the line, old earthenware pipes,
and a lack of upstream fixtures. Ten of the 100 locations
were chosen to be inspected with CCTV. Upon this
inspection no blockages were found, the homeowners were
also surveyed and confirmed satisfaction with the
performance of the new toilets.
Average Carry Distances
350g Sinking Waste
1.20-gallon
1-gallon Pressure- 1.28-gallon Gravity
Washdown
Assist
1st 2.9 m (9.4 ft) 1st 1.3 m (4.2 ft) 1st
3.7 m (12.2
Flush
Flush
Flush
ft)
2nd 7.4 m (24.1 2nd 4.4 m (14.4 2nd 6.2 m (20.3
Flush
ft)
Flush
ft)
Flush
ft)
Developed new dual flush toilet 1.2 gpf/0.8 gpf. After
testing in lab setting, ran a test by retrofitting 100 private
residences. Dr. Stephen Cummings, head of Research and
Development for Caroma stated,
Test Rig for Veritec Test
Sewer Plant Technology Impact
Through conversation with John Toore; maintenance
supervisor at the West Lafayette, Indiana water
treatment plant; it was found out that solid waste is 1%
of all of the waste entering the facilities. Mr. Toore
does not feel that the increased ratio of solid to liquid
waste will make any impact on the facility.
Gauley, B. (October 10, 2006). RE: WaterSense Drainline Carry Testing Results. Mississauga, ON: Veritec Consulting Inc.
Gauley, B., & Koeller, J. (March 11, 2005). Evaluation of Water-Efficient Toilet Technologies to Carry Waste in Drainlines: Canada Mortgage and Housing
Corporation.
Testing Times 'Down Under' (2007). World Plumbing Review(1), 4.
Wastewater Technology Fact Sheet - High-Efficiency Toilets (September 2000). Washington, D.C.: United States Environmental Protection Agency.
Professor Kirk Alter
Research Assistant: Russell Kahn
Department of Building Construction Management
Impact of Grey Water Systems
Aquifer Recharge
The impact that grey water systems have on
different aspects of concern are varied. Many
localities limit the use of untreated grey water use
to subsurface irrigation. This is typically
accomplished through a drip system (see
illustration) or mini leach fields. This limitation
of grey water to subsurface irrigation has the
unintended consequence of not only putting the
water and nutrients that it carries, commonly
nitrogen and phosphorous, directly back into the
ground to feed plant life but also to recharge the
aquifer. Use of greywater also limits the use of
potable water that is pulled from the municipal
systems . Irrigation is the single greatest use of
municipal water for households.
Typical grey water hookup to subsurface drip irrigation system
http://www.owue.water.ca.gov/docs/graywater_guide_book.pdf
Professor Kirk Alter
Research Assistant: Russell Kahn
Cost Data for Average 3bd/2bth House w/ Family of 4
Parts and Approximate Costs for the Brown
Family Graywater System*
Parts
Approximate Cost ($)
washing machine hook-up
connection parts
20
three-way diverter valve
28
pipe to sewer
4
pipe to tank
4
sanitary tee
3
shower/bath hook-up
connection parts
15
pipe to tank
4
bends
15
fittings
15
vent
13
Total: Plumbing Parts
55 gallon tank with lid
101
vent
13
inlet pipe
4
overflow pipe
4
drain pipe
4
backwater valve
4
water seal type trap
3
emergency drain ball valve
28
tank adapters ($20 each, one for each pipe)
60
union
12
Total: Tank Parts
Total: Pump
AND
Subsurface Drip Irrigation System
filter 140 mesh one-inch 25 gal/min
25
pipe: PVC class 200
12
fittings: schedule 40
15
drip lines: 112 emitters
46
valves ($25 each)
50
automatic flush valve ($2 each)
4
controller
50
switches
32
pressure reducing valve
15
compression T's
4
Total: Drip Parts
OR
Mini-leachfield
solid pipe
50
perforated pipe: 180 ft.
70
gravel, 18 in /130'/1' = 7 yds.
70
landscape filter fabric
40
Total: Leachfield Parts
GRAND TOTAL: DRIP
GRAND TOTAL: LEACHFIELD
*Cost for permit fees, rental equipment, professional installation, and maintenance not included.
$121
Storage
The state of Californinia requires that “the tank
must be solid, durable, watertight
when filled, and protected from corrosion. The
tank must be vented and have a locking gasketed
lid.” There must also be an overflow valve that is
permanently attached to a sewer line of septic
tank. Austin, TX considers grey water systems to
be adaptations of septic systems and treats them
as such.
$233
$150
$253
$230
$757
$734
A Sourcebook for Green and Sustainable Building - Graywater (January 13, 2007).
Gelt, J. Home Use of Graywater, Rainwater Conserves Water--and May Save Money.
. Graywater Systems (2008) Sustainable Building Sourcebook. Austin, TX: Sustainable Sources.
Using Graywater in Your Home Landscape Graywater Guide (January 1995). In D. o. W. R. S. o. California (Ed.): State of California.
Department of Building Construction Management
Most Effective Areas of Plumbing in Water Savings
1) Grey Water Recycling
Grey water can be used in place of potable water
in all areas of water use except for drinking ,
food prep and cleaning. Only 20% of the
potable water that we use is for these purposes.
This makes grey water an attractive alternative
for water uses such as irrigation and toilet
flushing.
Benefits
The ability to reuse water from our sinks,
showers and laundry facilities as toilet water,
in irrigation and in closed loop systems such as
HVAC&R can make a
serious impact on the
amount of water that is being used as well as limit
the amount spent on water and sewer costs. Ease
of use is major benefit of grey water use. Once
the system is installed it acts without the user
having to interact with it. The facility is plumbed to
feed the areas that
can use grey water to do so
and those that
cannot are plumbed for potable
water. There should be periodic checks on the
filtration system and cistern but that would
most likely be done by a professional, similar
to a service contract on a mechanical system.
Concerns
Cost of Implementing a grey water recycling
system. While this may not be an overly excessive
cost in new construction, it
is a concern in
existing structures. The ROI should be closely
examined to determine if this is a feasible option.
Local codes should also be referred to in order to
confirm that this is a legal option.
2) Rain Water Reclaimation
Similar to grey water, rain water can
be used in place of potable water in all
areas except for drinking , food prep
and cleaning.
Benefits
The benefits of rain water use are
the same as those for grey water
with one exception, in most areas,
with the appropriate roofing
material, rain water can be as clean
if not cleaner that municipal water.
Concerns
The concerns are the same as for
grey water.
Breakdown of US Urban Water Uses
Image from www.c2intl.com/waterconservation
Professor Kirk Alter
Research Assistant: Russell Kahn
3) Low–Flow Fixtures
The use of low–flow fixtures can make
a significant impact on the amount of
water that a facility uses. This area is
not limited to commodes and urinals.
The simple act of exchanging out a
shower head or aerator on a lavatory
can make an impact.
Benefits
For household use low-flow
showerheads and aerators can make a
larger impact than low-flow toilets.
We all shower and wash in our homes
but for many the amount of time that
we are not at home limits the use of
our toilets. At 1.6 gpf for a toilet and
2.5 gpm for a shower head it is easy to
see where more water is used. There
are also options such as foot pedals to
control sinks and vacuum assisted
commodes. Foot pedals allow water to
be turned off when it is not needed
without having to touch the hand
controls. This is a consideration for
locations like kitchens in residential
application or ideal in hospitals where
sanitation is imperative. The vacuum
assisted commode systems are already
starting to be used in hospitals.
Concerns
Commercial facilities should look at
the concerns with drainline carry of
wastes before spending the money on
low-flow commodes.
Future Areas of Research
•Actual cost of retrofitting a
facility with grey water
recycling and/or rain water
reclamation
•Technology to treat grey water
and rain water to tertiary
standards within reuse systems
and cost effectiveness
Low-Flow faucet in Union at University of North
Carolina
http://sustainability.unc.edu/Water/ConservationandEffici
ency/LowFlowFixtures/tabid/87/Default.aspx
References
Green Guide for Healthcare (20Anon (2004).
Grey water recycling device for re-use. [Jour]. Filtration and
Separation, 41(5), 18.
Leggett, D. J., Brown, R., Stanfield, G., Brewer, D., &
Holliday, E. (2001). Rainwater and greywater use in
buildings: decision - making for water conservation.
London: CIRIA.