How to Shut Off a Hot Water Heater

Whether you are working with a leak, repairing, or going on leave, knowing how to close your hot water heater properly is an important skill for the owner of any household. This can prevent floods, reduce the risk of electrical threats, and even save you money on your energy bill. But how do you really do it safely and correctly?

The process will vary slightly depending on whether you have a gas or electric water heater, and whether it’s a traditional tank model or a modern tankless unit. But don’t worry—we’re covering every angle in this comprehensive, easy-to-follow guide.

By the end, you’ll know exactly how to:

• Identify your water heater type
  
• Shut it off safely
  
• Decide if you also need to shut off the water supply
  
• Restart it when you’re ready
  

Let’s get started

Types of Hot Water Heaters Covered

This guide covers:

• Electric tank water heaters
  
• Gas tank water heaters
  
• Tankless models (briefly)
  While the focus is on traditional residential systems, the basic shutoff principles apply to nearly all types of units.
  

READ MORE: How to Relight Pilot Light on Water Heater

Safety First – Preparing for Shutoff

General Safety Precautions

Before touching your water heater, safety comes first. These are not small appliances—you’re dealing with scalding water, high pressure, and possibly natural gas or electricity.

Here’s what to do before anything else:

1. Clear the area around the heater
   
2. Dry any water spills to avoid slips
   
3. Have a flashlight handy if lighting is poor
   
4. Wear gloves and safety glasses if you’ll be draining or handling hot surfaces
   

Never attempt to shut off a water heater if:

• You smell gas—call your gas company or 911
  
• Water is gushing—shut off your main water supply first
  
• Electrical wires are exposed or wet—call an electrician
  

Tools You Might Need

Depending on your setup, you may need:

• A screwdriver (to remove access panels)
  
• Adjustable wrench or pliers (for older valve types)
  
• Garden hose (if you plan to drain the tank)
  
• Thermometer (to check water temp before draining)
  
• Multimeter (if troubleshooting an electric heater)
  

Having the right tools on hand will make the process smoother and safer.

Identifying Your Water Heater Type

Electric vs Gas Water Heaters

Before doing anything, you need to know whether you’re working with a gas or electric water heater. The shutoff process is different for each.

How to tell the difference:

• Electric heaters have a thick electrical cable leading into the top or side of the unit, and usually no venting system.
  
• Gas heaters have a gas line, burner access panel, and often a chimney or vent pipe.
  

Check the label if you’re still unsure—it usually lists the energy source and model type clearly.

Tank vs Tankless Units

This article focuses mostly on tank-style water heaters, which are the most common in homes.

Tankless models are typically wall-mounted and compact. They also require:

• Electric shutoff or gas valve shutoff
  
• Water inlet shutoff (usually marked “cold”)
  

The principles are similar but often simpler with tankless units since there’s no stored water to worry about.

READ MORE: How to Test a Water Heater Thermostat

How to Shut Off an Electric Water Heater

Step-by-Step Instructions

Here’s how to safely shut down an electric water heater:

1. Go to your circuit breaker panel
   
   • Find the breaker labeled “Water Heater” and flip it to the off position.
     
   • This completely cuts off power to the unit.
     
2. (Optional) Turn off the cold water supply
   
   • Locate the valve above the heater, usually on the right.
     
   • Turn it clockwise until it stops. This prevents new water from entering the tank.
     
3. Let the heater cool
   
   • If you need to drain it or work on it, wait at least 2 hours to avoid burns.
     
   • The water inside can remain hot for quite a while after shutoff.
     
4. Label or tag the breaker
   
   • Especially if you’re working on the unit, label the breaker with a warning to prevent accidental reactivation.
     

Additional Tips for Electric Units

• Never attempt to drain or open an electric heater before turning off the power. You risk serious injury.
  
• If you’re replacing heating elements or thermostats, double-check with a non-contact voltage tester to confirm power is off.
  
• For longer absences (vacations, seasonal shutdowns), some units have a vacation mode or can be safely turned off for weeks or months.
  

How to Shut Off a Gas Water Heater

Step-by-Step Instructions

If you have a gas water heater, the shutdown process is a little different and requires attention to both the gas and water systems. Follow these steps:

1. Turn the gas control valve to “OFF”
   
   • Locate the gas control knob on the thermostat—usually labeled “Pilot,” “On,” and “Off.”
     
   • Turn it to the “OFF” position. This stops the flow of gas to the burner and pilot light.
     
2. Turn off the cold water inlet
   
   • Locate the water shutoff valve above the unit and turn it clockwise to stop water from entering the tank.
     
   • This is especially important if you’re dealing with a leak.
     
3. (Optional) Shut off the main gas supply
   
   • For added safety, you can also turn off the gas shutoff valve on the pipe leading to the water heater.
     
   • Turn the handle so it’s perpendicular to the pipe—this cuts off gas flow entirely.
     
4. Let the heater cool
   
   • Wait at least an hour or more, depending on tank size, before performing any maintenance or draining. Water inside can remain dangerously hot.
     

What to Watch Out For with Gas Systems

Gas heaters come with unique safety concerns:

• Never attempt to shut off a gas appliance if you smell gas—leave the area immediately and call your utility company or 911.
  
• Don’t tamper with or disconnect the gas line unless you’re qualified or the valve is clearly accessible.
  
• If you’re unsure about the shutoff process, or if something feels “off,” always err on the side of caution and contact a professional.
  

Gas heaters often include pilot lights and thermocouples that may need relighting after shutdown—so make sure you understand how to restart the unit safely when you’re ready.

READ MORE: Why Is My Water Heater Making Noise?

Turning Off the Water Supply

Finding the Cold Water Shutoff Valve

Regardless of whether you’re working with gas or electric, there are cases where you’ll want to shut off the water as well:

• Leaking tank or connections
  
• Routine tank draining
  
• Replacing the unit or valves
  

The cold water shutoff valve is almost always located on the right side of the tank, just above the unit. It may look like a traditional faucet-style handle or a ball valve.

To shut it off:

• Faucet-style valve: Turn clockwise until it stops
  
• Ball valve: Turn the lever 90 degrees so it’s perpendicular to the pipe
  

Shutting off this valve stops new water from entering the tank, but it won’t remove the water that’s already inside.

When to Shut Off the Water Too

You should shut off both the water and power/gas supply if:

• There’s a visible leak around the base or pipe connections
  
• You’re draining the tank for maintenance or winterization
  
• The unit is being replaced or repaired
  
• You’re going away for an extended period and want to prevent pressure build-up or damage
  

If the cold water valve is stuck, don’t force it. That could cause a break. Instead, shut off the home’s main water valve and call a plumber to fix the issue safely.

What to Do After Shutoff

Draining the Tank (Optional)

Once your water heater is shut off, you may want (or need) to drain the tank—especially for maintenance, repair, or to prevent water damage in case of a leak.

Here’s how:

1. Turn off power/gas and water supply as described above.
   
2. Attach a garden hose to the drain valve at the bottom of the tank.
   
3. Place the other end of the hose in a floor drain or outside.
   
4. Open the drain valve and let the water flow out.
   
5. To speed things up, open a hot water faucet inside the house to let air into the tank.
   
6. After draining, close the valve and disconnect the hose.
   

Caution: The water inside may still be extremely hot, even hours after shutoff. Use gloves, avoid direct contact, and ensure pets and children are away.

Inspecting for Leaks or Damage

With the system powered down and water drained, it’s the perfect time to inspect for common issues like:

• Rusty or corroded tank base
  
• Leaky valves or joints
  
• Cracked fittings
  
• Moisture around the T&P valve
  

If you spot anything unusual, take photos and contact a licensed plumber. Early detection can prevent serious damage and costly repairs.

READ MORE: AO Smith vs Rheem Water Heater

When Should You Call a Professional?

Situations Too Risky for DIY

While many water heater shutoffs are easy enough for homeowners, some situations absolutely require a professional:

• Strong gas odors or hissing
  
• Major leaks or flooding
  
• Electrical arcing or damage
  
• Cracks in the tank
  
• You’re unfamiliar with plumbing or gas safety
  

Trying to DIY in these cases can not only make things worse—it can be dangerous. Don’t risk injury or damage to your home to save a few dollars.

Costs vs Benefits of Hiring Help

Hiring a plumber for a basic shutoff or inspection usually costs between $75 and $150, depending on your location. If a repair is needed, the cost will depend on the complexity and parts required.

But that small investment can save you:

• Thousands in water damage
  
• Hours of troubleshooting
  
• Risk of burns or gas leaks
  

If in doubt, call it out—it’s always better to be safe than sorry when dealing with plumbing or gas appliances.

Maintenance Tips to Avoid Emergencies

Regular Inspections

One of the best ways to prevent unexpected shutoffs or serious problems is through routine maintenance and inspections. A water heater is often out of sight—but it shouldn’t be out of mind.

Here’s what you should check regularly:

• Monthly:
  
  • Look around the tank for moisture or rust
    
  • Check for unusual noises like popping or rumbling
    
  • Inspect the area around the T&P valve for leaks
    
• Every 6 Months:
  
  • Test the T&P valve: Lift the lever briefly and let it snap back. A small amount of water should release into the drainpipe. If nothing happens, it may need replacing.
    
  • Flush the tank: Sediment builds up over time and can reduce efficiency or cause corrosion. Attach a garden hose to the drain valve and flush out a few gallons until clear.
    
• Annually:
  
  • Have a plumber check the anode rod, especially if your water is hard
    
  • Examine electrical/gas components for wear
    
  • Test thermostat accuracy and safety switches
    

Regular attention can extend the life of your water heater by several years—and reduce the risk of sudden, inconvenient failures.

Flushing and Testing Components

Flushing the tank and testing safety components is not just a recommendation—it’s essential for any homeowner who wants their system to last.

How to flush your water heater:

1. Turn off power/gas and let water cool.
   
2. Connect a garden hose to the drain valve.
   
3. Open the valve and allow several gallons to run out.
   
4. Look for sediment or discoloration—if present, flush more thoroughly.
   
5. Close valve, remove hose, and restore water supply and power.
   

Check components like:

• The thermostat (make sure it reads accurately)
  
• The heating element (electric models)
  
• The pilot light and thermocouple (gas models)
  

If you’re unsure how to test these parts, call in a pro for a yearly tune-up. It’s a small cost compared to major water heater repairs or replacements.

Conclusion

To know how to close a hot water heater is one of the essential homeowners skills that you hope you will never need – but you will have incredibly happy when the time comes. Whether it is an emergency, regular maintenance, or a seasonal shutdown, closing your heater properly can prevent injury, protect your home, and save you serious money.

To recap:

• Identify whether your heater is electric or gas
  
• Always shut off power or gas first
  
• Use the cold water shutoff valve to prevent flooding or backflow
  
• Allow the tank to cool completely before any work
  
• Perform regular maintenance to keep your system in top shape
  

And remember, if anything ever feels unsafe or unfamiliar—call a professional. Your safety and your home’s integrity are worth it.

With the steps outlined in this guide, you’re now equipped to confidently manage one of the most important appliances in your home.

FAQs

Q. Should I turn off my water heater when I go on vacation?

Yes, if you’ll be gone for more than a few days, turning off your water heater (or switching it to “vacation mode,” if available) can help save energy and prevent potential leaks. For electric units, turn off the breaker; for gas units, set the gas valve to “Vacation” or “Pilot.”

Q. Can I shut off just the hot water side?

Not exactly. Water heaters don’t have a “hot water line shutoff” because the hot water is pressurized and flows from the cold side. To stop hot water flow, you must shut off the cold water inlet valve, which stops the water feeding into the tank.

Q. How do I know if my water heater is electric or gas?

Check for a thick electrical cable and no venting system—this indicates electric. A gas valve, pilot light, and chimney or vent signal a gas model. If in doubt, check the unit’s label, which will list the energy source and safety instructions.

Q. How long does it take for a water heater to cool down?

It depends on the tank size and room temperature, but most water heaters take 2 to 3 hours to cool down enough for safe draining or inspection. To speed it up, you can run hot water from a tap until the tank empties partially.

Q. Is it safe to turn off my water heater myself?

Yes—as long as you follow safety guidelines, it’s safe for most homeowners to shut off a water heater. Always cut power or gas first, wait for cooling, and use the proper shutoff valves. If you encounter gas smells, electrical issues, or plumbing complications, call a professional right away.`