Final answer:
The drainage fixture unit value for a domestic dishwasher with an independent drain is typically around 2 DFUs. This value is important for designing a home's plumbing system. Improvements in the efficiency of appliances like dishwashers have contributed to reduced indoor water use overall.
Step-by-step explanation:
The question pertains to the drainage fixture unit (DFU) value of a domestic dishwasher with an independent drain. The DFU is a measure used in plumbing design to indicate the load on a drainage system from various fixtures, which in turn informs the sizing of pipes, traps, and venting systems. According to plumbing codes and standards, a typical domestic dishwasher has a drainage fixture unit value of around 2 DFUs. This value accounts for the rate at which the dishwasher discharges wastewater and the impact it has on the home's drainage system.
When discussing indoor water use, it's important to note that the efficiency of appliances like dishwashers has improved over the years, contributing to a decrease in total indoor water use. Efficient drain devices, possibly like those mentioned in FIGURE 12.28 which increase flow rate, may also play a part in ensuring that the discharged water from the dishwasher leaves the system effectively. The median water use in homes is approximately 125 gphd, reflecting variations in consumption by different devices and fixtures.
It's essential to follow local plumbing codes for exact specifications and to provide adequate infrastructure to support the efficient operation of a domestic dishwasher. Keeping in mind the efficiency improvements in home appliances and fixtures, particularly those related to water and wastewater systems, can lead to significant water conservation and better performance of the drainage system.