What is the purpose of using pressure zones on separate floors or areas of a building?

• A. To maximize water velocity on upper floors.
• B. To balance pressure and ensure acceptable fixture flow on all floors despite gravity effects.
• C. To isolate the cold supply from the hot water system.
• D. To reduce water quality by mixing with cold.

Answer: (B)

Pressure zones are used to keep water pressure at a consistent, usable level on every floor. Gravity makes pressure drop as you go higher, so a single, unregulated supply would deliver weaker flow to upper levels while potentially delivering too much pressure to lower ones. By dividing the building into zones and controlling the pressure in each one—often with valves, regulators, and sometimes booster pumps—the system maintains a target pressure in every zone. This ensures acceptable fixture flow on all floors and avoids the problems caused by large pressure differences due to height. It’s not about maximizing velocity, isolating cold from hot, or degrading water quality; it’s about balancing pressure so every fixture can perform reliably regardless of floor level.