Does Your Water Heater Need an Expansion Tank?

An expansion tank resembles a propane tank. It’s affixed to the top of your water heater. Its job is to alleviate pressure within your plumbing system.

Water expands as it heats. Fifty gallons in the tank can become 51 or 52 gallons when hot. That pressure has to go somewhere or it will strain the water heater, plumbing pipes, and connections -- that’s bad. This is a relatively new problem. In the past, the water main -- that’s the big pipe that supplies water to your home -- acted as a sort of pressure-relief valve. These days, however, many homes have a closed-loop plumbing system, meaning that incoming water can’t go back the way it came.

Because your water heater is the primary source of this stress, plumbers began attaching expansion tanks to absorb some of that pressure. The bottom half of the tank is filled with compressed air. As water expands, it forces a rubber diaphragm down to accommodate the added volume. This spares your faucets, toilet valves, and other fixtures from wearing out prematurely.

Here’s How to Tell if You Need an Expansion Tank

If you have a backflow prevention device connected to your main water shutoff valve, then you have a closed-loop system. (You know where the main water shutoff valve is, right?)

Closed-loop systems have a pressure regulator that controls the speed at which water is delivered into your home. The optimal water pressure is within 50 to 80 pounds per square inch. Thermal expansion from your water heater, however, can spike this pressure to dangerous levels. Watch for these signs that your home’s water pressure is too high:

  • Leaking faucets
  • A faulty fill valve in the toilet tank
  • Seals and stoppers failing on the dishwasher and washing machine
  • Leaking pipes

Turn to the Marietta Area Plumbing Experts

If your home is experiencing any of these symptoms, then an expansion tank may be the solution. To be sure, contact your friendly neighborhood plumbers at Plumb Doctor for a professional diagnosis. We’ll happily inspect your home’s plumbing system to determine the best course of action. To schedule your appointment, call (770) 293-7080.