A leaking hot water cylinder can cause a lot of stress and potential damage to your home. Whether it’s a minor drip or a significant leak, taking immediate action is crucial to prevent further issues. Here’s a step-by-step guide on what you should do if your hot water cylinder is leaking.

Identify the Source of the Leak

Check for Obvious Signs:

  • Look for water pooling around the base of the cylinder.
  • Check the valves, joints, and connections for signs of dripping or moisture.
  • Inspect the pressure relief valve, which can often be a source of leaks.

Listen for Sounds:

A hissing or dripping sound can indicate a leak from a specific area.

Turn Off the Power Supply

Electric Heaters:

Locate the circuit breaker for the hot water cylinder and switch it off to prevent electrical hazards.

Gas Heaters:

Turn off the gas supply by locating the gas valve and turning it to the off position.

Turn Off the Water Supply

Locate the Main Water Shutoff Valve:

This is usually found near the water meter or where the main water line enters your home. Turn it off to stop water from flowing into the cylinder.

Turn Off the Cold Water Inlet Valve:

This valve is typically located near the top of the hot water cylinder. Turning it off can help minimize the amount of water that leaks out.

Drain the Cylinder

Attach a Hose to the Drain Valve:

Locate the drain valve at the bottom of the cylinder. Attach a garden hose to the valve, ensuring the other end is placed in a safe area where the water can drain, such as a floor drain or outside.

Open the Drain Valve:

Carefully open the valve to allow the water to drain out. Be cautious as the water may be hot.

Open Hot Water Faucets:

To help the water drain more quickly, open a few hot water faucets around your home. This can also prevent a vacuum from forming inside the cylinder.

Assess the Damage

Check for Visible Damage:

Look for cracks, corrosion, or obvious wear on the cylinder and its components.

Determine the Severity:

Small leaks from valves or fittings might be fixable, while larger issues like cracks in the cylinder often require professional repair or replacement.

Temporary Fixes

Tighten Loose Connections:

Use a wrench to tighten any loose fittings or connections that might be the source of the leak.

Seal Small Leaks:

Apply plumber’s tape or epoxy putty to small leaks as a temporary fix until a professional can assess the situation.

Call a Professional

When to Call a Plumber:

If the leak is significant, if you cannot identify the source, or if temporary fixes do not work, it’s time to call a professional plumber.

Provide Detailed Information:

When contacting a plumber, give as much information as possible about the leak’s location and severity. This can help them prepare and possibly speed up the repair process.

Prevent Future Leaks

Regular Maintenance:

Schedule regular inspections and maintenance for your hot water cylinder. This includes checking valves, flushing the tank to remove sediment, and inspecting for signs of wear.

Install a Leak Detector:

Consider installing a leak detection system that can alert you to leaks early, potentially preventing significant damage.

Upgrade Old Systems:

If your hot water cylinder is old and prone to leaks, consider upgrading to a newer, more reliable model. Modern cylinders are often more efficient and come with advanced safety features.


A leaking hot water cylinder can be a major inconvenience and lead to significant water damage if not addressed promptly. By following these steps, you can mitigate the damage and take appropriate action to fix the leak. Remember, safety comes first, so turning off the power and water supply is crucial. For persistent or severe leaks, contacting a professional plumber is the best course of action. Regular maintenance and proactive measures can help prevent future leaks and extend the lifespan of your hot water cylinder.


Hot Water Solutions

Address: 3d Tait Place, Rosedale, Auckland 0632, New Zealand

Phone: 0800497658

Email: [email protected]

Website: https://hotwatersolutions.nz/

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