7.8 Building Hydrology Systems

7.8 Building Hydrology Systems

All buildings must use water for daily operation, but statistics indicate that currently employed buildings (residential or business) use too much of it. Centralized water supply and treatment creates an impression of abundance of water resource, but is virtually inefficient in showing how much water is actually used rather than wasted. Sustainable building designs target to improve that efficiency, implementing reuse systems within them and promoting water conservation through a number of technologies and strategies.

Here are some of the features of resource-efficient building hydrology systems:

In resource-efficient buildings, plumbing fixtures that use minimum amounts or zero water represent important water conservation technologies. These technologies include:

• composting toilets, low-flow toilet (0.8 gal/flush), waterless urinals;
• low-flow shower heads (less than 2.5 gal/min);
• low-flow faucets (less than 2.5 gal/min), metered faucets.

Gray water systems allow reuse of the water coming from sinks and washing machines for toilet flushing and irrigation. Gray water can be reused directly or after cleaning with on-site sand filters.

Waste heat recovery systems can capture heat from the used gray water going down the drain and use it for heating the clean water. Heat recovery can be especially efficient in facilities with extensive hot water use (e.g., laundries, locker rooms).

Instead of trying to list all possible technologies and tactics related to sustainable water management in buildings and characterize them generally, it would be more useful to study a good example of practical implementation. Here is a report that describes a few case studies of sustainable buildings, which includes quite detailed characterization of their water management features.