You’re getting cold water but no hot because something in the hot side of your system isn’t heating or isn’t letting hot water through.

What’s Usually Going Wrong

In most homes, it’s one of these:

  • Water heater issue (most common). The heater isn’t heating at all, so every tap only gives cold water.
  • Failed thermostat. The “brain” that tells the heater to turn on has died or is misreading the temperature, so it never heats.
  • Broken heating element (electric). The element burned out or is covered in sediment and can’t heat the water.
  • Tripped breaker / no power (electric). The water heater has lost power, so it’s just a cold tank.
  • Pilot/burner problem (gas). Pilot out, gas valve issue, or burner not firing even if the pilot is lit.
  • Sediment buildup. Thick mineral buildup in the tank makes heating inefficient or blocks hot water outlet.
  • Valve or mixing issue. A differential/mixing valve or a specific faucet cartridge is blocking hot water flow while allowing cold.

Quick Checks You Can Safely Do

Only do what you’re comfortable with; anything involving gas or wiring is for a pro.

  1. Is it one tap or the whole house?
    • No hot water everywhere → likely the water heater or a central valve.
 * Only one sink/shower affected → likely that faucet’s cartridge or mixing valve.
  1. Look at the water heater:
    • Gas unit:
      • Check if the pilot is lit and if you smell gas (if you do, leave and call the gas company or a pro immediately).
 * Electric unit:
   * Check the breaker panel for a tripped double‑pole breaker; reset once if safe. If it trips again, call an electrician or plumber.
  1. Check the temperature setting and any visible reset.
    • Make sure the thermostat isn’t turned way down. Some electric heaters have a reset button under a small panel.
  1. If only one fixture is cold:
    • Kitchen/bath faucet: the internal cartridge can fail and block hot while letting cold through.
 * Shower: the shower mixing valve can stick or fail and mix only cold.

When You Should Call a Pro (Recommended)

Get a licensed plumber or qualified tech if:

  • No hot water anywhere and breaker resets don’t help or keep tripping.
  • You’re not comfortable opening panels, touching gas controls, or working around electricity.
  • Hot water comes and goes, or only certain rooms lack hot water (could be valves, partial blockages, or more complex mixing issues).

They can:

  • Test thermostats and heating elements with proper tools.
  • Safely relight/repair gas components.
  • Replace faulty cartridges, mixing valves, or clogged lines.

Simple Example Scenario

  • If your entire house only has cold water and your electric water heater’s breaker has tripped, the likely cause is a failed heating element or internal electrical fault. Reset once; if it trips again, stop and call a pro.
  • If the kitchen sink has hot water but the bathroom shower is only cold, it’s probably that shower’s mixing valve or cartridge, not the whole water heater.

If you tell me:

  • Whether you have gas or electric,
  • Whether any tap in the house still gets hot,
    I can help you narrow it down more and suggest exactly what to check next.

Information gathered from public forums or data available on the internet and portrayed here.