How to Descale Your Tankless Water Heater Properly

A tankless water heater is one of the smartest upgrades you can make in your home. It provides endless hot water, saves energy, and takes up less space compared to traditional storage water heaters. But like any appliance, it requires proper upkeep to run efficiently. One of the most important steps in maintaining performance is learning how to descale your tankless water heater.

Hard water contains minerals like calcium and magnesium that can accumulate inside the heat exchanger over time. This buildup, also known as scale, reduces efficiency, increases energy bills, and may even shorten the lifespan of your system. In this guide, we’ll walk you through the tankless water heater descaling process, from signs your system needs attention to a step-by-step DIY descaling tankless water heater approach.

At Michigan HVACR, we help homeowners maintain their systems properly so they can enjoy reliable hot water without costly repairs.

Why Descaling Is Important

Before learning how to descale a tankless water heater, it’s essential to understand why it matters.

Improves efficiency – Mineral buildup restricts water flow and heat transfer.
Prevents damage – Scale can cause overheating or damage to the heat exchanger.
Saves money – A clean system consumes less energy.
Extends lifespan – Proper care helps your water heater last 15–20 years.

If ignored, scale buildup may cause expensive breakdowns or force premature replacement.

Signs Your Tankless Water Heater Needs Descaling

Not sure if your unit needs cleaning? Here are common signs your tankless water heater needs descaling:

Reduced hot water flow or inconsistent temperatures
Strange noises, like popping or rumbling inside the unit
Increased energy bills without a change in usage
Error codes displayed on the heater’s control panel
Hot water taking longer to reach faucets

If you notice any of these issues, it’s time to perform a tankless water heater cleaning and flushing.

Tankless Water Heater Descaling Process

Here’s a step-by-step guide to the tankless water heater descaling process.

Tools & Materials You’ll Need:

A descaling solution or white vinegar (at least 3–4 gallons)
Submersible pump
Two washing machine hoses
A 5-gallon bucket
Adjustable wrench
Screwdriver

Step 1: Turn Off Power and Water Supply

For safety, switch off the power supply and close both the cold-water inlet and hot-water outlet valves.

Step 2: Connect Hoses

Attach the hoses to the service valves—one for the cold-water inlet and one for the hot-water outlet. Place the other ends of the hoses in a 5-gallon bucket.

Step 3: Add Solution

Fill the bucket with white vinegar or a professional descaling solution. This is the start of your tankless water heater vinegar flush.

Step 4: Start the Pump

Submerge the pump in the solution and turn it on. The liquid will circulate through the water heater, dissolving mineral deposits.

Step 5: Flush for 45–60 Minutes

Let the solution run through the system for about an hour to thoroughly clean the heat exchanger.

Step 6: Rinse With Fresh Water

Drain the vinegar solution and replace it with clean water. Run the pump again for 10–15 minutes to remove any leftover residue.

Step 7: Reconnect and Restart

Remove the hoses, close service valves, and turn the water and power back on. Your system should now operate at peak efficiency.

DIY Descaling Tankless Water Heater vs. Professional Service

Many homeowners attempt DIY descaling tankless water heater methods, especially with vinegar flushes. While it’s possible to do on your own, professional service is often recommended because:

Technicians use advanced descaling solutions.
They can spot other issues like leaks or venting problems.
Professional cleaning ensures warranty compliance.

If you’re confident with tools, you can do it yourself once a year. Otherwise, scheduling professional maintenance with Michigan HVACR provides extra peace of mind.

How Often Should You Descale?

The frequency of descaling depends on your water quality.

Hard water areas – Every 6 months
Moderate water areas – Once a year
With a water softener – Every 18–24 months

Regular cleaning ensures your system operates efficiently while avoiding costly breakdowns.

Tankless Water Heater Cleaning and Flushing Tips

Always install isolation valves during installation for easier maintenance.
Use white vinegar if you prefer a non-toxic, affordable cleaning solution.
Don’t skip the fresh water flush after descaling—it prevents vinegar taste in your water.
Keep a record of maintenance dates to stay consistent.
If your system shows error codes, call a professional rather than ignoring them.

Final Thoughts

Knowing how to properly descale your tankless water heater is crucial for efficiency, reliability, and longevity. Whether you follow a DIY descaling tankless water heater method with a vinegar flush or hire professionals for a thorough tankless water heater cleaning and flushing, regular care ensures you’ll enjoy endless hot water for years to come.

At Michigan HVACR, we specialize in tankless water heater installation, maintenance, and descaling services. If you’re unsure about the process or want expert service, our team is here to help keep your system running at its best.

FAQs

Q1: How often should I descale my tankless water heater?
Most units should be descaled once a year, but homes with hard water may need it every 6 months.

Q2: Can I use vinegar to descale my tankless water heater?
Yes, a tankless water heater vinegar flush is safe and effective for dissolving mineral buildup.

Q3: What happens if I don’t descale my tankless water heater?
Mineral buildup reduces efficiency, increases energy bills, and can damage the heat exchanger.

Q4: Should I hire a professional for descaling?
DIY is possible, but professionals ensure deeper cleaning and inspect for other potential issues.

Q5: What are the signs my system needs descaling?
Reduced water flow, strange noises, error codes, or rising utility bills are common signs.