MEP Engineering · Engineering Glossary
The domestic water system in a building is the network of pipes that delivers potable cold water from the utility main or well to all plumbing fixtures, and the hot water system that heats and distributes hot water throughout the building. Plumbing engineers design the domestic water system for adequate pressure, flow, and water quality.
The domestic water system includes the service entrance and meter, backflow preventers, pressure reducing valves (if utility pressure exceeds 80 psi), the cold water distribution piping, water heaters or a central hot water plant, hot water distribution piping, and a hot water recirculation system for larger buildings. Pipe sizing is based on the fixture unit method (per the applicable plumbing code — IPC, UPC, or state equivalent) to ensure adequate flow and pressure at all fixtures under peak demand. Water heater sizing accounts for the number of fixtures, the peak hourly demand, and the recovery rate. In healthcare, laboratory, and food service facilities, additional treatment (softening, filtration, or purification) may be required. Apex Grid designs domestic water systems where project-specific credentials and authorization are verified.
Apex Grid Engineering maintains this glossary as a resource for architects, contractors, developers, and property owners who encounter unfamiliar engineering terminology on their projects.
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