RESULTS: DATA LOGGING

The data logging revealed a range of water fixture leaks and problems, including constant leaks and toilet flushing at a repeating, constant interval. Although all water use events were identified in each trace to make sure that no toilet use events were misidentified, analysis of problems was restricted to those specifically related to toilet functioning.

Problems discovered for toilet models installed in 10 or more households are shown in Table 2, along with a listing of toilet problems according to flush valve type used in the toilet and the total for all households.

High Flush Volume

There were 219 low-consumption rebate toilets found in 166 houses (in four of the 170 sample homes the low-consumption rebate toilets had been replaced). These toilets had an average flush volume of 1.98 gallons per flush (gpf), or approximately 24 percent higher than the 1.6 gallons per flush they were designed to use.

Investigation by Aquacraft Engineering, Inc. into the functioning of data loggers and the end- use-analysis software, using simultaneous flow traces on the main water meter and a meter installed on the hot water line, indicates that small faucet usage on the order of 0.1 gallons can be hidden in the volume recorded for the toilet flush event. This faucet usage occurs as people wash their hands after using the toilet. However, Aquacraft reports that inclusion of an extra 0.1 gallons in the toilet flush volume does not occur every time faucet use immediately follows a toilet flush. In addition, the impact of a possible inflation of toilet flush volume depends on the frequency with which faucet use follows a toilet flush. Observation of traces in this study indicates that faucet use follows toilet use only some of the time.

Another measure of the frequency of low-consumption toilets with high flush volumes is the percentage of homes with a low-consumption toilet with an average flush volume greater than 2.2 gpf, or the highest allowed flush volume allowed for any of the flushes used in meeting the AMSE/ANSI low-consumption testing protocol. The average flush volume of at least one low- consumption rebate toilet was found to be greater than 2.2 gpf in 26.5 percent of homes.

Low-consumption toilets with the tube and bell flush mechanism were shown to have the highest percentage homes with high flush volumes at 44.4 percent, which was well above the average of 26.5 percent for all homes. There were two models of toilets included in this category, the Mansfield Allegro and the Kilgore (Ifö) Cascade. The Allegro was the more numerous of the two toilet models, with 15 of the 18 total homes in which a toilet with a tube and bell style mechanism was installed. The Allegro had the second highest percentage of homes with high flush volumes compared to other individual toilet models, at 40 percent.

Homes with toilets having a toilet dam and a standard flapper had the second highest percentage of problems compared to other flush mechanisms, with 26.8 percent or just above average for all homes. Of the brands for which there were traces from 10 or more homes, the Lamosa Sahara had the highest percentage of homes with high flush volumes, at 60 percent. This toilet uses a toilet dam and a flapper. Homes with other toilet models with a toilet dam performed much better than the Lamosa Sahara. The Eljer Preserver had 23.1 percent of homes with high flush volumes. The Aqualine Aqua Saver, had 20.0 percent of homes with high flush volumes.

Table 2. Low-Consumption Toilet Problems by Flush Valve Type and by Toilet Model

1. Number of homes from which this toilet model or toilet with this type of flush mechanism was removed.

2. Calculation of Some Problem includes homes from which toilets were removed due to poor function. Pressurized Quantum toilets were removed from three homes due to poor function. A Wellworth Lite with an early-close flapper was removed from one home because the toilet was rendered inoperable by the actions of children in the household, not due to poor function.

3. Toilet models for which there were data from at least 10 households.

E = Early-close Flapper, P = Pressurized, T = Tube and Bell, D = Toilet Dam and Standard Flapper, S = Standard Flapper

The generally poor performance of some brands of toilet with the toilet dam and flapper flush mechanism such as the Lamosa Sahara compared to other brands is an interesting finding. It is possible that toilet dams dislodge in the tank easier with some models than with others, or that dams are intentionally removed. Also, the flappers originally provided with the toilet may perform better in those toilets than generic replacement flappers. It is difficult to single out a cause with the information gathered in this study.

Low-consumption toilets with a standard flapper as the flush mechanism had the next highest percentage of homes with high flush volumes at 26.1 percent, or just below average for all homes. All toilets in this category were made by Universal Rundle, and Atlas was most numerous of the toilets, with 20 of the 23 total homes. Thirty percent of households with the Atlas had high flush volumes.

Homes with low-consumption toilets with early-close flappers had the next lowest percentage of high flush volumes, at 25.0 percent. The Wellworth Lite is the only model installed in 10 or more households which uses an early-close flapper. Twenty-three percent of households with Wellworth Lite toilets had high flush volumes, which was below the average for all households (26.5%). This implies early-close flappers, despite the ease with which they can be replaced with standard flappers with 3.5 gallon flush volumes, may not be worse than other mechanisms in allowing higher flush volumes after seven years of service.

Pressurized toilets were the most successful at delivering low-volume flushes. Only 9.1 percent of homes with pressurized toilets recorded high flush volumes. The Quantum was the only pressurized toilet brand installed in 10 or more homes. Compared to all other individual toilet models, the Quantum had the lowest percentage of homes (10%) with flush volumes greater than 2.2 gallons per flush.

Double Flushing

Chronic double flushing of low-consumption rebate toilets occurred in 23 of 211 toilets in the 162 homes for which there were data(6). This means there were toilets requiring chronic double flushing in 14.2 percent of homes, constituting 10.9 percent of rebated low-consumption toilets studied. This is roughly equivalent to 10.9 percent of rebated low-consumption toilets needing to be double flushed once a day. For reference, a 1992 survey of Los Angeles Water and Power toilet rebate customers with many of the same models of low-consumption toilet when they were new, reported that 9 percent of low-consumption toilets required double flushing several times a week, 4 percent said their low-consumption toilet required double flushing once a day, and 5 percent said double flushing was required several times per day (Wirthlin Group 1992).

The rate of double flushing can be influenced by human factors, such as habits formed over time, as well as toilet construction. This may be reflected in the fact that double flushing occurs in non-low-consumption toilets as well as low-consumption toilets. A comparison of the rate of chronic double flushing between rebate low-consumption toilets and non-low-consumption toilets can give an indication of the increase in the rate of double flushing attributable to low- consumption construction.

There were 76 non-low-consumption toilets functioning in 72 of the 163 homes for which there were readings. Five of the these non-low-consumption toilets showed chronic double flushing, or 6.6 percent of non-low-consumption toilets. The difference between the 6.6 percent of non- low-consumption toilets requiring double flushing and the 10.9 percent of low-consumption rebate toilets requiring double flushing, although not large, is statistically significant at the 95 percent confidence interval.

Low-consumption toilets with a standard flapper as the flush valve had the highest percentage of homes with double flushing problems, at 21.7 percent. These toilets did not use either a toilet dam or an early-close flapper, but instead incorporated other design changes to achieve the 1.6 gallon flush. The most numerous toilet in this category, the Atlas, had the third highest percentage of chronic double flushing among toilet models, at 20.0 percent.

Homes with toilets with a toilet dam and standard flapper as the flush mechanism had the second highest percentage of homes with double flushing problems, at 17.1 percent. There was a wide variation in performance between the Preserver, the Lamosa Sahara, and the Aqua Saver. The Preserver had the highest percentage of chronic double flushing among toilet models, at 30.8 percent of homes, while none of the homes with a Lamosa Sahara had a problem with chronic double flushing. Twenty percent of homes with an Aqua Saver had double flushing problems.

Early-close flapper toilets showed a below average percentage of homes with chronic double flushing at 13.3 percent (compared to 14.2% average). Toilets with a tube and bell mechanism had problems in 11.1 percent of homes.

Pressurized toilets had the lowest percentage of homes with chronic double flushing, at 9.1 percent. Among individual toilet models, the Quantum had the second lowest percentage of chronic double flushing at 10 percent of homes in which they were installed.

6. There were four homes where it could not be determined whether a toilet with a high flush volume was the expected low-consumption toilet. Therefore, these four homes were not used in calculating the percentage of homes with low-consumption toilets with high flush volumes. As a result, data were available for 162 homes instead of 166.

Flush-Valve Flapper Leaks

A total of 24 homes had recurring flapper leaks out of the 140 which had low-consumption rebate toilets that used flappers instead of some other flush mechanisms. In 17 of these instances it could be verified that a Tucson Water rebate program low-consumption toilet was responsible for a regular-interval flapper leak. In three the cases, another toilet in the house had the flapper leak, not the Tucson Water low-consumption toilet. In the remaining four instances, there was no way to determine whether the leak was due to the rebate toilet, or to another toilet in the household.

The average volume per tank refill due to a flapper leak was 0.48 gallons. The period of time between refills ranged from 6 minutes to 4 hours, and averaged 85 minutes.

Flapper valve leaks occurred somewhat more often in toilets with a toilet dam and a standard flapper (16.1% of homes) than in those with an early-close flapper (13.3% of homes). Toilets with a standard flapper without the toilet dam design had the lowest percentage of flapper leaks, at 8.7 percent of homes.

The Preserver, which has a toilet dam, had the highest percentage of homes with flapper leaks, at 23.1 percent. Homes with the Atlas had the lowest percentage of flapper leaks, at 10.0 percent.

Homes With Some Toilet Function Problem

Seventy-two of the 165 households for which there was a reading had one or more problems with the functioning of their low-consumption toilets, or 42.9 percent of homes. Four households were disregarded because it could not be determined whether a flapper leak was from the rebated low-consumption toilet or another toilet in the household. However, three homes in which the low-consumption rebate toilets had been replaced because of poor functioning were included in the calculation for this category, leaving 165 homes.

Homes with pressurized toilets had the lowest percentage of overall problems, with 35.7 percent. Among individual toilet brands, the Quantum had the second lowest percentage at 38.5 percent. The rating for pressurized toilets in general and the Quantum specifically would have been significantly better, had not Quantums in three homes been removed for performance-related problems.

Toilets with early-close flappers had the second lowest percentage of homes with some problem. Among individual models of toilets, households with the Wellworth Lite had the lowest percentage of problems, with 37.5 percent.

Low-consumption toilets with a standard flapper also had a below average number of homes with some problem, at 39.1 percent of homes. The most numerous toilet in this category, the Atlas, had some problem in 40 percent of homes.

One or more problems were detected in 51.2 percent of homes with toilets with toilet dams. This figure is similar to the 55.6 percent of homes with the tube and bell mechanism that had some problem. The two worst performing individual models of toilets used a toilet dam. The Preserver had the second highest percentage of homes with problems at 61.5 percent, while the Lamosa Sahara had the highest percentage of homes with some problem at 80.0 percent.