We used a questionnaire to obtain information on the years of use and the reasons for the replacement of residential plumbing equipment. The average number of years of use ranged from 19 to 20 years in the case of toilet bowls, bathroom fittings, kitchen units, and washstands. The average number of years of use for toilet seats, shower units, faucets, bathtubs, and stoves ranged from 11 to 17 years. These values were approximated by the Weibull distribution. Generally, people tended to replace toilet bowls and shower heads fixed above bathtubs much before the aforementioned average time span, because of the need for energy and water saving.
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