What is a common cause of water hammer in plumbing systems?

Water hammer is a phenomenon that occurs when a fluid in motion is suddenly stopped or forced to change direction, causing a pressure surge in the plumbing system. A common cause of this issue is the lack of air chambers in the plumbing. Air chambers serve as a cushion or buffer that absorbs the shock of the sudden stop, significantly reducing the pressure surges that can lead to water hammer.

In the absence of these air chambers, there's no mechanism to absorb the kinetic energy of the moving water when a valve is abruptly closed. As a result, the pressure can spike, leading to the characteristic banging noise associated with water hammer.

The other options may contribute to plumbing issues but do not directly address the cause of water hammer in the same way that the absence of air chambers does. For instance, while faulty shutoff valves or low static water pressure can create other complications within a plumbing system, they do not specifically relate to the sudden pressure changes that characterize water hammer. Loose piping may create rattling sounds, but it’s not the fundamental reason for the pressure surge inherent in water hammer scenarios.