CSLB C-36 Plumbing ContractorService, Repair, and MaintenanceHard
A client reports an intermittent loss of hot water at their faucets, but the water heater itself (a gas tank-type) appears to be functioning, with a pilot light on and no obvious leaks. The issue seems to resolve itself after a short period, only to recur later. What is the most likely cause?
- AA faulty temperature and pressure (T&P) relief valve.
- BExcessive sediment buildup at the bottom of the tank.
- CA clogged cold water inlet screen.
- DA failing dip tube inside the water heater tank.
Show answer & explanationAnswer & explanation
Correct answer: D. A failing dip tube inside the water heater tank.
A failing dip tube, which delivers cold water to the bottom of the tank, can break or detach. When this happens, cold water mixes with hot water at the top of the tank, leading to intermittent or significantly reduced hot water supply, even if the heating element/burner is working. The effect can be intermittent if the broken piece shifts.
Why the other options are wrong
- A. A faulty T&P valve would typically leak or discharge water, not cause intermittent hot water loss.
- B. Excessive sediment buildup causes rumbling noises and reduced overall hot water capacity, but typically a consistent, not intermittent, lack of hot water.
- C. A clogged cold water inlet screen would restrict water flow into the tank, leading to low water pressure for hot water, not necessarily intermittent hot water loss with normal pressure.
Water Heater Dip Tube Failure
A problem where the dip tube, which directs cold water to the bottom of a tank-type water heater, breaks or deteriorates, leading to cold water mixing with hot water at the top.
- Cold water mixes with hot water
- Intermittent or reduced hot water
- Heater appears to be working
- Requires tank draining and dip tube replacement
Memory trick: Hot then cold? Dip tube's old, story untold!