2024 – This ‘look-back’ at the water consumption levels of major indoor appliances and plumbing fixtures provides some rather startling accomplishments.  Download this one-page summary of 40 years of reductions.

2022 – Orange County Water District and Yorba Linda Water District opened their 25mgpd per- and poly-fluoroalkyl substances (PFAS) Treatment Plant, the nation’s largest ion exchange (IX) treatment plant for PFAS removal.  As a result, the YLWD was able to re-open 10 wells that were previously shut down due to PFAS.  Read the article by AWWA.

October 2017 – A comprehensive research report by Dan Cole related to Dr. Roy Hunter’s original water demand calculations and supply piping sizes. This report is intended to provide a fresh look at the sizing supply piping in residential applications considering the very significant reductions in fixture flush and flow rates over the past 80 years.

April 2017 – Water-efficient toilets could potentially save up to 170 billion potable gallons of water per year in the 5 states, according to new research by Koeller and Company for the AWE and PMI. The “Saturation Study of Non-Efficient Water Closets in Key States” focused on Arizona, California, Colorado, Georgia and Texas and found that over 13 million aging toilets are unnecessarily wasting precious potable water in those 5 states.

This two-page discussion outlines reasons why MaP PREMIUM-rated toilets (1.06 gallon or 4.0 litres per flush) are NOT necessarily appropriate for all installations. While the PREMIUM-rated models are excellent flush performers, its the ‘environment’ into which they are installed that is the true issue.  Read the considerations that MUST be evaluated before installing or mandating these ultra high-efficiency toilet fixtures.

2003 – Check this article in Contractor Magazine from 2003 and the reaction of plumbing industry representatives to the new ‘bean curd test’!  Since then, the MaP testing protocol has found its way into WaterSense and the national plumbing standard for toilets.

2016 – A summary of the results of a 5-question online survey by MaP Testing.  How often are paper seat covers used and how are they positioned on the bowl in commercial restrooms?

February 2016 – Alliance for Water Efficiency (AWE) white paper titled “The Status of Legislation, Regulation, Codes and Standards on Indoor Plumbing Water Efficiency”, which focuses primarily on provisions in current ‘green’ codes, standards, and rating systems in the U.S.  Among the findings and recommendations, the white paper provides three very interesting and revealing tables of comparison.  We urge you to download and review the entire paper.

October 2012 — A report on water savings from a water utility program directed at removing 5,000 aging high-volume (3.5 gallon/13 litre and above) toilets and replacing them with High-Efficiency Toilets (HETs) in 80 multi-family residential and commercial properties.  Prepared for California’s Santa Clara Valley Water District.

Water Wasted by Leaking Shower Diverters
April 2014 – AN INDEPENDENT MaP RESEARCH REPORT – Field study by MaP Testing as a follow-up the Taitem Engineering study 3 years earlier.  This study encompassed the field inspection of 453 aging diverters installed in multi-family residential occupancies in the province of Ontario. The occurrence of leaking diverters was similar to that found in the Taitem study, but leakage rates were different. Download the report for study findings.

April 2014 – A detailed report by Dan Cole on his research related to Dr. Roy Hunter’s original calculations and methodology of nearly 100 years ago (still being used today in the plumbing code) and how they relate to today’s conditions as to fixture units and pipe sizing.   The report appears in the Spring 2014 edition of the IAPMO OFFICIAL magazine.

2013 – By Dr Steve Cummings, this presentation summarizes the findings from Australian research into building drainline systems conducted over the past several years, including pipe junctions, solid waste transport, effects of toilet paper on drainlines, alternate drainline profile designs, and relationships to the North American PERC study.

2018 – White paper summarizing some of the unintended consequences of past water efficiency and conservation programs for both premise plumbing and municipal systems.

February 2017 – AN INDEPENDENT MaP RESEARCH REPORT:  Has showering and water consumption changed over the past 17 years?  Comparing results from the two North American Residential End-Use Studies of Water (1999 and 2016), the report examines how showering habits have changed and resultant changes in water savings.

January 2017 – AN INDEPENDENT MaP RESEARCH REPORT:  When do people take their showers?  Intuitively, of course, we all think we know when most people shower.  Are we right or wrong?  This report analyzes data from the 1999 and 2016 Residential End-Use Studies of Water to see how showering habits may have changed over the 17-year interval.

January 2017 – AN INDEPENDENT MaP RESEARCH SUMMARY:  Has residential faucet water consumption (lavatory and kitchen) changed over the past 17 years?  Comparing results from the two North American Residential End-Use Studies of Water (1999 and 2016), this summary chart shows how little (if any) savings have been achieved, in spite of a very significant reduction in average faucet flow rates.  QUESTION: Are further mandated reductions in faucet flow rates really justified by expected water savings in the home?  YOU decide!!

Originally issued November 2011 – Another residential end-use study reveals more about Australian water use habits.  Go to TABLES 9, 10, 11, and 12 (PAGES 31 & 32) to learn how dual-flush toilets are used in the Australian residential ‘real world’.  Made available by permission from the Urban Water Security Research Alliance.  Check out their Technical Report No. 47:  South East Queensland Residential End Use Study: Final Report. 

1943 – In your leisure time, listen to this interesting story from August 10 (NOTE: 29mb and 30 minutes long).

May 2004 – A field study of the actual use of pool covers rebated by a Southern California water agency. Are the recipients of these rebates really just “free riders”?

December 2009 – Read this article about the proliferation of numerous ‘green’ guidelines, standards, and code requirements.  Good or bad?

View a chart that compares commercial and residential dishwasher water use with hand washing (using a standard Energy Star ‘load’).

2008 –  This study commissioned by Australia’s Federal WELS Scheme reveals that instantaneous gas-fired water heaters wasted 17 to 24 gallons per day.

2010 – This study by Brookhaven National Laboratory for the Minnesota Office of Energy Security concluded that some potential water savings do exist.

2011 – What do others say? AskTheBuilder.com

2008 – Study by SBW Consulting for Seattle energy and water utilities quantified the savings potential by visit and measuring consumption in a sample of 71 homes in the region. Before and after measurements of water and energy taken as efficient products replaced existing products.

2006 – Study by Lawrence Berkeley National Laboratory evaluating different action scenarios directed at reducing water and energy consumption in showers. Also addresses the multiple showerhead issue as well as tub spout leakage.

2011 – Analysis (CASE Report) of multiple-head showers and single showerheads by the California Codes and Standards Team dealing with reduced flows and resulting energy savings.  Incorporates findings of the 2010 Mowris study and evaluates customer satisfaction, lower flow rates, and other factors.

2010 – Study by Mowris et.al. of showerhead performance and customer satisfaction with a view toward developing California showerhead flow and performance requirements.
Download PDF of study presentation >>

2011 – Report by Veritec Inc. on a user-satisfaction study of 12 different showerheads used by 23 study participants.  This study was one of many consulted by WaterSense in developing their showerhead specification.

June 2012 – Article in the IAPMO Official magazine, which summarizes the results of studies showing sensor-activated faucets do not save water.  Read this short article to understand why.

2008 – Are urine-separating toilets in our future? Read this!

2008 – Report by manufacturers disputing concerns over drainline build-up of solids. Technical and non-technical issues are discussed.

2006 – In 2004-2005, Dr. Mete Demiriz of Gelsenkirchen University of Applied Sciences in Gelsenkirchen Germany completed a study of dry (non-water) urinals in the University’s very extensive laboratory facilities dedicated to plumbing technologies. When the study report and presentation were reviewed by water efficiency advocates and by plumbing system professionals in North America, it set off alarms. READ ABOUT THOSE ISSUES and the ensuing debate.

August 2011 – Read this interesting article from Plumbing Connection Magazine (permission to post granted by Connection Magazines Pty Ltd.)

September 2011 – Read this article with an intimate view on the topic by the highly respected Julius Ballanco, P.E.

November 1998 – The Metropolitan Water District of Southern California  focused on the compatibility (or incompatibility) of flappers found in the traditional after-market (at Home Depot, Lowe’s, and hardware stores) with the typical gravity-fed toilet fixtures found in most residential households. A total of 50 aftermarket flappers were fitted to 24 different toilets. Flush volumes were measured and reported.

April 2008 – Why were toilet flappers getting so much attention from water conservation professionals and manufacturers in the 1990s? Read about the evolution of the flapper problems through the 1990s until today.

These three materials studies by one of Metropolitan Water District of Southern California’s engineering laboratories were a catalyst in the plumbing industry’s advancements in flapper materials durability.

MWD (1998) Toilet Flapper Materials Integrity Tests 

MWD (2000) Toilet Flapper Materials Integrity Tests 

MWD (2001) Supplement – Toilet Flapper Materials Integrity Tests 

2004 – This comprehensive field study of the durability of toilet flappers, and the habits and practices of homeowners with respect to flapper replacement and use of in-tank bowl cleaning tablets, involved the inspection of 892 randomly selected toilet fixtures in homes throughout California. Products from 14 manufacturers with production dates from 1992 to 2002 were measured for flush volume and subjected to a flapper inspection.

2006 – With funding support from the U.S. Department of Energy, Texas A&M’s Energy Systems Lab conducted a drainline transport study. The final study report was released in 2006.

2008 – Study report from the Environment Agency looking at the “Impact of reductions in water demand on wastewater collection and treatment”  This 81-page report looks at building drainline impacts and sewer infrastructure.

March 2005 – Due to concerns over reduced flows in building drainlines from water-efficient fixtures and appliances, eight Canadian organizations sponsored the “Evaluation of Water-Efficient Toilet Technologies to Carry Waste in Drainlines.” Those organizations were: Canada Mortgage and Housing Corporation, the cities of Calgary and Toronto, the province of Manitoba, the regions of Peel, Waterloo, and Durham, and the Ontario Ministry of Municipal Affairs and Housing.

July 2006 – In connection with release of its specification for High-Efficiency Tank-Type toilets, WaterSense commissioned a study of drainline transport related to toilets in residential dwellings. This brief, 4-page analysis follows on the heels of the March 2005 residential drainline study.

July 2011 – A 5-page brief summarizing current concerns over waste transport in building drainlines and municipal sewers.

World Plumbing Review (2007) Testing Times Down Under – Low Flow Toilets and Drainline Carry – An article in a 2007 issue (Issue 1, 2007) covers extensive drainline waste transport testing performed in Australia. Once you get through some of the sales “pitch” for a manufacturer’s products, there are some interesting observations.

June 2012 – Read this interesting article from Australia on ‘flushable wipes’.  They may be ‘flushable’ but are they right for our building drainlines?

The PERC is comprised of 6 organizations (IAPMO, ICC,    ASPE, PMI, PHCC-NA, AWE), each committed to achieving efficiency, infrastructure integrity, and public health and safety. PERC’s first priority was to study commercial building drainlines and the transport of waste when those drainlines are starved of water. Phase 1 of the PERC study is complete and a study report released. The Phase 2 work plan is available; testing has now begun (to be completed in 2015). Go to the PERC page for further information.

June 2012 – Following up on the drainline study done in 2005, we looked again at drainline waste transport, comparing the North American siphonic toilet design with the European / Australian washdown toilet design. Which design results in longer waste transport in typical residential installations?  Also in 2012 – Mechanical Business (Australia) magazine published a short article on the siphonic-washdown controversy. Read the 2-page summary comparingthe two design approaches.   

October 2000 – This study, sponsored by the City of Phoenix and the U.S. Bureau of Reclamation, was the first study to look at 1.6g (6.0L) toilet fixtures of 1991-92 vintage to assess their performance after 8 years of use. The University of Arizona Research Center data-logged 170 homes and analyzed the results for flush volume, double-flushing, leakage and other factors. This was followed by household surveys to determine the types of installed toilet fixtures and owner satisfaction with those fixtures.

May 2001 – The Metropolitan Water District of Southern California undertook to test three new toilet models that had recently been introduced into the marketplace. Eight fixtures were each subjected to 250,000 flush cycles. Where potential problems appeared, manufacturers addressed those problems and improved products resulted.

2002 – The National Association of Home Builders Research Center, in cooperation with Seattle and East Bay MUD, released a report on their toilet performance study. The report details the results of extensive testing (with sponges and paper wads) on 49 of the most popular low-flow tank-type toilets in North America.

   In addition to the final report, download these 2 comparison documents:  (1) test results index, (2) comparing results with CR Magazine.

November 2003 – Read this DEBATE between advocates of two different toilet technologies and learn of the advantages and disadvantages of each.

August 2005 – While there has been considerable research into the performance and water savings related to residential toilet fixtures, little work had been completed by 2005 on flushometer valve fixtures for commercial applications. This flushometer testing program included flush volume and performance testing of seven popular commercial bowl models with seven different flushometer valves. Sponsored by the City of Toronto, and the Regions of Durham and Waterloo in Ontario, Canada.

March 2007 – This laboratory study evaluated the current testing media used in the U.S. and Canada to certify toilet fixtures for sale and installation here. Testing with sponges and plastic balls and pellets are required in both the U.S. and Canadian plumbing standards, but how realistic is any test that uses such materials to test for flush performance? This study report is a first scientific step in examining how test results using these materials compare with those obtained through MaP testing.

2009 – Non-Residential HETs and Drainline Carry – Bill Gauley and John Koeller issued a CAUTION STATEMENT in 2009 in which they outline the conditions under which HETs probably should and should NOT be used in non-residential applications. This is part of on-going research on this important topic.  We will post further information, clarification, and recommendations as more information becomes available.

September 2009 — A report on the water savings and resulting reduction in maintenance service calls when 1,030 aging 3.5 gallon (13 Litre) gravity-fed toilets were replaced with 1.0 gallon (3.8 Litre) pressure-assist toilets in the Park 55 Wyndham Hotel in downtown San Francisco.

March 2010 – AN INDEPENDENT MaP RESEARCH PROJECT:  This study (among others) says they do not save water.  In fact, water use INCREASES when a manually activated toilet fixture valve is replaced with a sensor-activated valve. Read this revealing study to learn more.

August 2011 — A report on the water savings and maintenance service calls associated with replacment of 192 aging 3.5 gallon (13 Litre) fixtures with 1.0 gallon (3.8 Litre) pressure-assist toilet fixtures in a downtown San Francisco apartment building.

July 2011– A report on the water savings and customer satisfaction with Niagara Stealth 0.8 gallon (3 Litres) vacuum-assisted toilet fixtures installed in older homes in Southern California.

September 2011 — A report on water savings from a water utility program directed at removing aging inefficient toilets and replacing them with High-Efficiency Toilets (HETs) in residential and commercial applications.  Prepared for California’s Sonoma County Water Agency.

February 2012 — Read this Gauley/Koeller discussion of efficient toilets and their impact upon drainlines in your home.

Updated December 2023 – Designing or equipping a day care center? A preschool, kindergarten, or primary facility and need ‘child-sized’ water closets? This listing includes both gravity-fed, tank-type toilets as well as bowls for flushometer applications. Bowl heights range from 10 inches (254mm) to 14 inches (356mm).  (Note that adult-sized conventional height bowls and ADA-classified bowls generally range from 15 to 17 inches, or 380mm to 430mm)

2015 – Phantom flushes of flushometer valve/bowl combination toilets plague many commercial establishments.  Without regular and proper maintenance of flush valves and sensors, significant water waste can occur.  Read this report by the Guardian.

July 2009 – Testing disclosed that most dual-flush retrofit products for tank-type toilets are NOT universal in their application (that is, they only fit a few models of gravity-fed tank-type toilets), do NOT always reduce water consumption, and may FAIL to meet minimum code requirements related to health and safety!  Read the CAUTION STATEMENT directed at these issues.    NOTE: These same concerns do NOT exist with dual-flush conversion products for flushometer valve/bowl combination toilets.

February 2013 – Download this short 280-word summary of the 3 studies (linked above) regarding the use of the ‘reduced’ flush option in residential and commercial-institutional settings.

June 2005 – This residential END-USE STUDY reveals that, in Australia, showers are the largest water use inside the home….next comes clothes washers….then toilets. Quite different from North America, where the toilet is usually the dominant water user.  View TABLE 14 in this Yarra Valley report to see just how residents actually use dual-flush toilets.

As more and more toilet manufacturers are offering dual-flush toilets, it is important to understand how such designs can provide benefits.
2010 – Read the summary of an analysis done in 2008 of the various studies conducted over the previous 10 years relating to dual-flush ‘ratios’ from Water Efficiency magazine:
Water-Efficiency_magazine-Dual_Flush_Savings-Aqucraft—An_Analysis_of_Field Data

A discussion of the calculation of the ‘effective’ flush volume and how the ‘ratio’ affects that volume.
READ MORE HERE ON THE HISTORY OF DUAL-FLUSH 

January 2013 — Read this behavioral economics study report that looks at the actual use of dual-flush handles on flushometer toilets in a typical building.  The study addressed the question of whether or not people actually choose the ‘reduced flush’ option.  Surprising or intuitive conclusions?  You had better read this one!
A summary is also  found in the Dual flush article-study summary-Arocha copy.

May 2018 – Summary report (9 pages) of the results of 6-month online survey on the MaP website: covered installed residential shower systems, showering habits, and hot water delivery times for the shower.  Approximately 3,000 individuals participated in the survey. AN INDEPENDENT MaP RESEARCH REPORT

How much water is wasted with leaking shower diverters?
2011 – This “tech tip” by Taitem Engineering provides valuable insight on the amount of water wasted by leaking shower diverters in residences.  Data was obtained by performance testing a variety of common diverter models in a laboratory.  This study (along with others) provided information for the U.S. EPA initiative to develop a WaterSense specification for diverters.

December 1999 – The Metropolitan Water District of Southern California commissioned Honeywell DMC to perform a survey of 1,300 individuals who installed new gravity-fed 1.6-gpf (6.0 Lpf) toilets in 1998 and 1999. A total of 13 different toilet models were rated by customers on a variety of important performance factors, the results being reported in this document.

2024 – A recently completed 3^rd-party evaluation analysis (Dickinson & Gauley) identifies volumetric water savings achieved by 112 multi-residential apartment buildings located in California that installed the DrizzleX (www.drizzlex.com) sub-metering system – a system that involves separately sub-metering each water supply for all fixtures in all apartment units (including both hot and cold where applicable). Dickinson/Gauley calculated an average savings of 56 gallons per suite per day – equating to an average savings of 28.6% of PRE demands.

2022 – the California Energy Commission opened a docket directed at updating CEC provisions on water closets (toilets).  This is the proposal submitted by Gauley and Koeller (and others) in response to the CEC’s Request for Information on the topic.