What is the function of a hydropneumatic (bladder) tank in a water distribution system?

• A. Damps pressure fluctuations, provides short-term storage, reduces pump cycling, and improves water hammer control
• B. Increases pump head irrespective of demand
• C. Filters sediment from water
• D. Acts as the primary storage reservoir

Answer: (A)

Hydropneumatic bladder tanks are all about smoothing pressure and reducing how often the pump has to turn on and off. They store water under pressure using a bladder that separates water from compressed air. When water is drawn, the air cushion compresses and helps push water out without the pump starting up every time there’s a small demand change. When demand falls, the stored water keeps the system pressure up briefly, which reduces rapid on/off cycling and cuts down on water hammer by absorbing sudden pressure surges. This combination provides short-term storage right in the distribution network and helps maintain a steadier pressure.

So the best description is that the tank dampens pressure fluctuations, provides short-term storage, reduces pump cycling, and improves water hammer control. It doesn’t raise pump head irrespective of demand, it doesn’t filter sediment, and it isn’t meant to be the primary storage reservoir.