Top 4 Reasons Why Tankless Water Heaters LEAK

Tankless water heaters are designed to provide efficient, on-demand hot water, but when leaks occur, they can quickly turn into expensive problems. In most cases, leaks are not caused by manufacturing defects but by conditions around the system itself.

Below are the top three reasons tankless water heaters leak and what homeowners can do to prevent these issues.

1. Hard Water and Scale Buildup

Hard water is one of the leading causes of tankless water heater leaks. Minerals like calcium and magnesium accumulate inside the unit, creating scale that can damage pipes and reduce performance over time.

Prevention Tips:

• Flushing Your Tankless Water Heater: 
  • Run a cleaning solution through your unit yearly or twice a year to remove scale buildup.
    
  • Flushing protects your heater and prolongs its lifespan.
    
• Water Filtration Options:
  
  • Whole house water softener
    
  • Whole house carbon filter
    
  • Flow-Tek system
    
  • Point-of-use filters like Scale RX or Heater Trigger
    

2 . High Water Pressure

Excessive water pressure can strain your tankless water heater and cause leaks or even damage the unit. Maintaining proper pressure is essential for safe operation.

Prevention Tips:

• Ensure water pressure complies with local regulations, which vary by area (for example, Los Angeles County caps residential pressure at 80 psi).
• Install or adjust a pressure regulator to maintain safe levels.
  
• Use an expansion tank to absorb pressure spikes caused by thermal expansion.
  

3. Incorrect Installation

Improper Tankless Water Heaters installation can lead to leaks, poor performance, and even safety risks. Even minor errors in fittings or venting can cause serious problems over time.

Prevention Tips:

• All connections and fittings must be secure; the system is only as strong as its weakest point.
  
• Ensure proper tankless water heater venting to manage condensation and prevent leaks.
  
• Hire a certified plumber to guarantee installation meets manufacturer specifications.

If you’re unsure about your installation or notice leaks,  repairHVACnow can connect you with certified technicians in your area. They ensure your tankless water heater is installed correctly, with secure fittings and proper venting, protecting your unit from future leaks and maintaining optimal performance.

4. Temperature and Power Settings

Incorrect settings can contribute to leaks and reduce efficiency. Tankless water heaters require precise temperature and power configurations to function safely.

Key Considerations:

• Check tankless water heater power requirements to ensure proper electrical or gas supply.
  
• Avoid setting the tankless water heater temperature too high; recommended range is 120°F–130°F.
  
• Proper temperature and power settings help prevent overheating and scale buildup.
  

Tankless Water Heater Maintenance Checklist

• Flush the system and remove scale using a cleaning kit
  
• Test water hardness and use filters or softeners if needed
  
• Check water pressure, valves, and expansion tanks
  
• Inspect fittings, venting, and power connections
  
• Adjust temperature settings and monitor hot water performance
  
• Look for corrosion, leaks, or unusual noises
  

Final Thoughts

Tankless water heaters can deliver reliable, efficient performance, but they require proper installation and regular maintenance. Most leaks are preventable by addressing hard water issues, controlling water pressure, and ensuring professional installation and venting.

If you notice any signs of a leak or want to ensure your system is maintained properly, you should consider calling a qualified technician through  repairHVACnow, who can connect you with experienced local professionals to inspect and service your tankless water heater.

Frequently Asked Questions (FAQs

1. How much do tankless water heaters cost to install?

Installation typically ranges from $1,500 to $3,500 depending on unit size and complexity.

2. How much electricity does a tankless water heater use?

They use electricity on demand, making them more efficient than traditional tank heaters.

3. How long does a tankless hot water heater last?

With proper maintenance, they can last 20 years or more.

4. How much propane does a tankless water heater use?

Propane usage depends on unit size and household hot water demand.

5. How to reset a tankless water heater?

Most units have a reset button; follow the manufacturer’s instructions.

6. How to choose a tankless water heater?

Consider household size, fuel type, power requirements, and venting needs.

7. What size electric tankless water heater do I need?

Choose a unit that meets your peak flow rate and hot water needs.

8. What size tankless water heater is needed for a family of 4?

A unit with a 6–9 GPM (gallons per minute) flow rate usually suffices for four people.