Introduction
Tankless water heaters can accumulate mineral deposits over time, especially in homes with hard water. This buildup can reduce efficiency, restrict water flow, and shorten the unit’s lifespan. Regular cleaning helps maintain performance and prevent costly repairs.
What You'll Need
Steps
Turn off the power and water supply to the unit.
Close the hot and cold isolation valves.
Attach hoses to the hot and cold service ports and place the other ends in a bucket.
Connect the submersible pump to the cold-side hose.
Fill the bucket with vinegar (or descaling solution) and submerge the pump.
Open the service valves and run the pump for 45 minutes to circulate the solution.
Turn off the pump and discard the used solution.
Flush the system with clean water for 5 minutes.
Disconnect the hoses, close service ports, and reopen isolation valves.
Restore power and water to the heater.
Alternative Methods
• Use a commercial tankless water heater descaling kit
• Hire a professional for deep cleaning or annual maintenance
• Install a water softener to reduce future mineral buildup
What NOT to Do
• Do not skip turning off the power or gas
• Do not use harsh chemicals not approved for water heaters
• Do not run the unit with service valves closed
FAQs
How often should I clean my tankless water heater?
Most units should be cleaned once a year, but homes with hard water may need cleaning every 6 months.
Can I use something other than vinegar?
Yes, commercial descaling solutions work well and may be more effective for heavy mineral buildup.
What happens if I don’t clean the heater?
Mineral deposits can clog the system, reduce efficiency, cause temperature issues, and eventually damage internal components.
This article is for informational purposes only. Always follow manufacturer instructions and use proper safety precautions. You assume all risk for any actions you take based on this guide.
Articles
Read our latest guides
Discover step-by-step methods for removing stains and cleaning every type of surface.
How to Clean Oil Paint Brushes
Learn how to safely and effectively clean oil paint brushes without damaging the bristles.
Read more
How to Clean a Cricut Mat
Learn how to safely clean a Cricut mat without damaging its adhesive, so it stays sticky and ready for crafting.
Read more
How to Clean Acrylic Paint Brushes
Learn how to remove acrylic paint from your brushes before it dries, helping them last longer and perform better.
Read more