Why might a building have two independent cold water feeds, and what is a typical arrangement?

• A. To color-code pipes.
• B. Redundancy for reliability or to supply different pressure zones; often two feeds to separate manifolds or PRV zones.
• C. To make installation faster.
• D. To reduce chlorine content.

Answer: (B)

Having two independent cold water feeds is about reliability and pressure management in larger buildings. The redundancy means that if one line is shut off for maintenance or suffers a fault, the other line can still supply water, reducing downtime. At the same time, feeding separate pressure zones lets different parts of the building receive appropriate pressure without overstressing the whole system—for example, upper floors don’t have to rely on a single pressure setting that might be too high for lower floors.

In practice you’ll often see two incoming feeds from the street entering the building, each with its own shut-off valve, and each feeding its own distribution path or manifold. Each path has its own pressure-regulating valve (PRV) or set of controls to maintain the desired pressure for that zone, along with isolation valves and sometimes a backflow preventer as required by code. This arrangement keeps the system flexible and maintainable: one feed can be serviced without shutting down the entire cold-water supply, and pressure can be tailored to different sections of the building.

This setup isn’t intended for color-coding pipes, speeding up installation, or reducing chlorine content.