Green Kitchens & Baths
The History of Water Conservation In American Toilets
Prior to 1970, there was little concern for water conservation in the United States. Only when shortages started to become significant did actions to conserve start. Two kinds of shortages appeared -- insufficient water availability, and where water was not short, inadequate waste treatment capacity.
At that time, Europe was much more conscious of water conservation. The typical European water closet (WC) used between six and nine liters [1-1/2 to 2 gallons-per-flush or “gpf”] or about 30 percent to 40 percent less than the typical toilet sold through the United States and Canada. Major differences existed between European and North American (NA) WC styles - the biggest seeable difference being that European WCs had very small water-spots. As a result, they were much more susceptible to staining than toilets installed here.
European toilets were also quite different hydraulically in that they incorporated a “wash-out” concept versus NA designs that used siphon action. European bathrooms typically had and used scrub-brushes. Because of the larger water-spot and swirl during the building of the siphon, American bathrooms rarely had a scrub brush. Their toilets “appeared” to be much cleaner.
Water delivery systems in Europe were [are] considerably different than in the U.S. and Canada. In Europe, the water supply system within the building is most commonly supplied by gravity flow from a rooftop storage tank. Water is pumped to the roof storage tank by either a pressurized pipe or booster pump system from a reservoir. In the United States, almost all water is supplied under pressure from the water utility directly to the fixtures [faucets, toilets, showers, water heater, etc.]. Pressurize delivery systems dominate even in rural areas - where a pump [booster] pulls water from a well and pushes it into a [pressurized] storage tank in the basement. As the water moves into the storage tank it compresses air. The combination effectively charges the contents so that it can push water through the system when demanded [e.g. faucet opened, etc.].
In North America, the typical 1970-style water closet used between 5 1/2 and 8 gpf. One-piece toilets typically used as much as 12 gpf. Water closet designers, at that time, paid little attention to consumption. Their dominate concern being adequate extraction and drainline carry.
Massive flush consumption of the typical North American water closet was not always that way. Back in the 1920s, for example, the common toilet used about two gpf. Because its storage vessel affixed to the wall up by the ceiling, the greater head pressure resulted in a much higher injection velocity of water into the bowl. The dominate bowl design of the 20s was called a “washdown” in which the siphonic trapway was located in the front of the bowl [versus the back in today's designs]. Since the higher input flow velocity established siphon action more quickly, less water was needed. In the late 1930s, with the introduction of new hydraulic styles called “siphon-jet” and “reverse-trap,” water consumption started to increase because these new “close-coupled” toilet designs had their storage tanks sitting directly on the back of the bowl. While esthetically more appealing, this dramatically lowered the stored potential energy. As a result, water consumption/flush necessarily increased. More volume was needed to initiate siphon action. In effect, volume was substituted for velocity.
Also in the late 1920s, the Case Manufacturing Co., of Buffalo, N.Y. introduced the first one-piece water closet. While this new innovation used considerably more water, the style featured a much quieter flush and more appealing looks.
Throughout the 1930s, 40s and 50s, water closet consumption per flush continued to increase until reaching a plateau in the 1960s of five to seven gpf for two-piece close coupled WCs and eight to 12 gpf for one-piece units. The only pressure-assisted WCs available at that time were flushometer-valve activated [commercial] fixtures that consumed consistently around 5-1/2 to 6 gallons. During this era, while manufacturers cared little about consumption, they did care about efficacy. Thus, as long as water was very cheap and essentially available in unlimited supplies, everything was fine. However, when you fool with Mother Nature, she often hits back.
Excessive Consumption is RecognizedIn the 1960s, droughts hit the northeast and western states. Elsewhere, other areas began running out of waste treatment capacity. As demand for water and/or waste treatment demand began reaching existing capacities, construction moratoriums were instituted more and more frequently. Because moratoriums stop construction and economic activity, builders and other parties began demanding help. One area that was quickly recognized was the [excessive] consumption of the toilet. Studies showed that almost 50 percent of all water consumed within a residential structure was used by the toilets. In fact, it was the largest consumer of water outside of industrial and agricultural use.
American Standard (A/S) recognized the situation by introducing their Cadet™ Watersaver - America's first close-coupled, two-piece gravity activated WC that consumed 3-1/2 gpf - a nominal 36 percent reduction. At the same time, the Washington Suburban Sanitary Commission (WSSC), which supplies water and sewer services in the Maryland suburbs of Washington, D.C., was having severe capacity shortages. Recognizing that the toilet was a major user of their limited commodity, the WSSC mandated that all WCs installed thereafter within their jurisdiction must not consume more than 3-1/2 GPG. Other communities with supply and/or treatment capacity shortages quickly started to follow the WSSC lead.
Led by the WSSC mandate, the A/S 3-1/2 gpf disruptive technology set off a stampede among fixture manufacturers offering watersaver type toilets in order to compete. Unfortunately, many of these new “watersaver” WCs did NOT work very well. Some were simply conventional 5-1/2 gpf combos with a partition in the storage tank to let out less water. Others used a smaller tank on the same [5-1/2 gpf] bowl. These 5-1/2 type bowls, whose hydraulic designs needed more water to establish an adequate siphon, were thus starved and extracted poorly - thus requiring double and even triple flushes to get rid of the waste.
Up to this time, the American National Standard for water closets [upon which almost all local codes are based] dealt only with design. Consumption was not even mentioned. However, with acute shortages developing all across America, in the mid-1970s the call went out for a WC standard that dealt with consumption as well.
Revising the StandardsThe American National Standards Institute (ANSI) activated its A112.19.2 Water Closet Standard Working Group (WG) and charged it with reviewing and updating the existing standard to meet America's current needs. Patrick Higgins chaired the WG whose membership was dominated primarily by fixture manufacture representatives plus a few code and independent participants.
One of the first actions that the WG recognized was, if the revised standard was to have water consumption limits, it also had to have [minimum] performance requirements. Since there never had been hydraulic performance requirements in any previous ANSI vitreous china standard, the WG had to start from the beginning. The National Bureau of Standards agreed to fund the project. The actual research was conducted at the Davidson Labs of Stevens Institute of Technology under the supervision of Professor Thomas Konen. From this study came the first American National Standard for water closets based on performance as well as design. The new standard established:
1. Water closet classifications based on overall consumption -- “water saver” for toilet's whose total consumption did not exceed 3-1/2 gallons/flush and “conventional” for toilets that consumed more than 3-1/2 gpf.
2. A series of laboratory extraction tests aimed at measuring the minimum extraction characteristics needed for a toilet in the field -- simulated heavy, medium and light bulk specimen materials plus a minimum drainline-carry requirement.
All tests were pass/fail.
While the newly revised and updated ANSI standard was adopted by city and state codes almost immediately, it was almost obsolete before the printing dried since two disruptive innovations were also occurring at that time:
1. Introduction of the first pressure-flush [flushometer-tank activated] water closet by Mansfield Plumbing in 1984.
The Mansfield Quantum™ shook the fixture industry at its foundations because while fixture manufacturers were struggling to produce acceptable 3-1/2 “gravity” activated toilets, this new [flushometer-tank] technology allowed a close-coupled WC, connected to a conventional 3/8” supply, to have the performance of the “conventional” 5-1/2 gpf toilet. The flushometer-tank seemed to answer the concerns in the market place for a good performing toilet.
2. Introduction of the six-liter [1-1/2 gpf] gravity activated WC.
Responding to the threat of the flushometer-tank technology as well as 6-liter mandates in several water short states, vitreous china manufacturers responded by introducing European style 6-liter WCs.
Like their 3-1/2 gpf cousins, the original six-liter [gravity activated] WCs performed poorly. Double flushes and clogs were common. Part of the problem was that the American consumer was not ready for such a radical design change - different appearance; small water-spot; and skid marks and clogs - all for the goal of saving water. User frustration resulted in code authorities all across America demanding a standard that realistically simulated, in a lab test, real world performance requirements. The updated 1990 edition:
1. Recognized the new six liter WC classification called “Low Consumption,”
2. Further refined the extraction tests contained within the earlier version; and,
3. Retained [the standard's most controversial requirement] the drainline carry test.
The drainline carry test was controversial because, from the bowl designer's view, it stood in the way of his solving the public's biggest complaint about low consumption WCs - clogs. In the standards meetings, WC manufacturers fought hard for its elimination because needing to design WCs that they had trapways large enough to avoid clogs made it difficult, if not impossible, to meet the 40-foot minimum drainline carry requirement using gravity activation.
Because, with a fixed amount of energy, larger diameter trapways reduced discharge thrust, the bowl designer was caught between the “rock and the hard-place” -- less clogs in the bowl could mean more clogs in the drainline.
The WG fixture manufacturer majority maintained that the bowl's only job was to discharge the waste into the drainage system. From there, carry was someone else's problem. In the end, the fixture manufacturer's position was overridden by strong opposition from the architects and design engineers.
Ironically, of all the performance tests contained in ANSI A112.19.2, the drainline carry test has the most field validity. Its requirement correlates to the [proven] performance of 5-1/2 gpf WCs - which everyone knows worked. The test was developed by determining the actual carry capability of 5-1/2 gpf toilets in a laboratory environment where [using the current ANSI standard test protocol] it was determined that those old “gas-guzzler's” maximum carry capability was 58 feet. Based on this knowledge, the WG dropped that down to 40 feet recognizing that other drain tributaries also fed fluid to help flow and the belief that 5-1/2 gpf toilets probably used more water than needed.
Technological InnovationsDespite their frustration in not getting the drainline carry provision eliminated from the ANSI standard, the fixture industry has come a long way technologically. Two interesting innovations that have helped make gravity activation somewhat more acceptable to the American consumer have been the slot rim and the 3-inch flush valve. Both have contributed toward obtaining faster [higher velocity] flow of water from the storage tank through the bowl and into the drainline. The faster discharge means that the gravity designers have improved their efficiency in converting the potential energy in extraction efficiency. This, plus lowered performance expectancy by the typical American, and low selling prices have made 1.6 gpf gravity toilets passably acceptable to Americans.
Where is toilet technology going in the next 10 years? On the surface, the domestic plumbing industry has done wonders in reducing the waste of America's water. Consider the toilet's recent history (see Typical WC Consumption/Flush graph).
Between 1960 and today, the “typical” bread-n-butter toilet's consumption, the largest consumer of water in the house, has been reduced by over 80 percent. Is that as far as it can go? The good news is that my crystal ball suggests that the era of the one-gallon flush is approaching. My crystal ball also says that unless America takes another step backward in its toilet performance expectations, the only technology capable of meeting that demand for yet lower consumption/flush is the flushometer-tank [e.g. pressure-assist flushing device].
America's water shortage is not going away. Consider just one of the several serious problems facing parts of America - Southern California's water shortfall. Published articles project the region running out of sufficient water supplies within the next 15 years. Because the Federal courts have restricted their use of the Colorado River, their only alternatives are to find new technology that will further reduce demand while maintaining the standard of living OR reduce population and the standard of living. The latter is not appealing.
Thus, my short-term vision sees the one-gallon flush winning.