No hot water after winterization

Quick Answer:

Start by confirming any winter shutoff valves are fully open and remove protective caps. Check the water heater (power or pilot) and run hot at another faucet. If the shower is the only cold fixture, try cycling the shower valve between hot and cold several times to free a sticky cartridge. If valves are stuck or you’re unsure, call a plumber.

Why This Happens

Winterization often involves closing isolated shutoff valves and putting caps on outside fixtures. If a valve wasn’t fully reopened or a cap left in place, hot water can’t reach the shower. Cartridges and ceramic discs in shower valves can also seize after months of no use. Finally, air trapped in lines or a water heater that wasn’t restarted can leave you without hot water.

Step-by-Step What to Do

1. Confirm winter valves and caps

Locate any winter shutoff valves you used (inside near the water main, at the water heater, or at the outdoor hose bibs). Make sure each valve is turned fully to the open position and remove any plastic caps or covers that were installed for winter.

2. Check the water heater

Verify the heater has power or a lit pilot if it’s gas. For electric heaters, check the breaker; for gas, confirm the pilot is on and the gas valve is open. Do not disassemble the heater or relight a pilot if you’re not comfortable — call a professional if you aren’t sure.

3. Test other fixtures

Run hot water at a sink or tub. If hot water is available elsewhere, the issue is likely the shower valve rather than the heater. If no hot water is available anywhere, the problem is upstream (heater, main valve, or supply isolation).

4. Cycle the shower valve to free a stuck cartridge

Slowly move the shower control fully to cold, then fully to hot, and repeat this motion several times. This can free mineral buildup or a slightly sticky cartridge so hot water flows. Run the water while cycling so any trapped material can flush out.

5. Flush and run hot for several minutes

After opening any valves and cycling the shower, allow hot water to run for 5–10 minutes to purge air and cold water from the line. Check for improved temperature and any signs of a leak.

6. Check for obvious problems and retest

• Look for closed local shutoffs near the water heater or behind walls where winterization work was done.
• Confirm any anti-scald or thermostatic controls haven’t been reset to a low temperature.

If only your shower is affected, check the note below for related situations: Shower cold only in morning. If hot water drops when several showers run at once, see No hot water when multiple showers used.

What Not to Do

• Don’t force winter valves or caps if they’re frozen or stuck — you can break a valve or pipe.
• Don’t attempt to relight a gas pilot or work on the heater if you don’t know the correct procedure; natural gas can be dangerous.
• If you’re unsure what valves should be open or how your system is set up, a plumber is appropriate to avoid causing damage.

When to Call a Professional

• Valves or caps are stuck or appear frozen.
• No hot water at any fixture after you’ve checked the heater and valves.
• You see leaks, corrosion, or hear unusual noises from the heater or pipes.
• You’re uncomfortable working on gas or electrical components of the water heater.

Safety Notes

• Hot water can cause severe scalding — test temperature carefully and keep children and pets away while testing.
• Do not force frozen parts; cracking a valve or pipe can lead to major water damage when it thaws.
• If you smell gas or suspect a gas leak, leave the building and contact your gas supplier or emergency services immediately.

Common Homeowner Questions

• Why is hot water only out at the shower? Likely a stuck shower cartridge or a local shutoff not opened; cycle the valve and check nearby valves.
• How long should I run the water after opening valves? Run hot water for 5–10 minutes to purge air and cold water from the lines.
• Can I fix a stuck valve myself? If it’s not frozen and you can move it gently, you can try cycling; if it’s hard or frozen, call a plumber.