How Often Should I Have My Tankless Water Heater Flushed?

A tankless water heater is small on the outside but busy on the inside. Every day it handles showers, dishes, laundry, and handwashing without storing a huge tank of hot water. That efficiency is a big advantage, yet it also means the internal parts work in tight spaces where mineral buildup can cause trouble.

Regular flushing is the simplest way to protect that system. It keeps hot water flowing the way it should, helps the heater run efficiently, and lowers the chance of sudden breakdowns that interrupt daily life.

Why Flushing a Tankless Water Heater Matters

Flushing clears out the mineral deposits that slowly settle inside the heater. Those deposits, mainly calcium and magnesium, stick to the hot metal surfaces and grow thicker with time. Even a small amount of buildup can change how the unit heats water.

As scale builds, the heater has to work harder and longer to reach the same temperature. That extra effort shows up as rising energy bills and more strain on the components. Over time, this strain can shorten the lifespan of the unit and create avoidable tankless water heater issues that lead to repairs or replacement.

How Tankless Systems Actually Heat Your Water

Tankless units heat water only when a tap opens, so they work on demand instead of storing a large tank of hot water. That saves space and can cut energy waste, but it also means the inside of the heater relies on clear, open pathways.

Inside the unit, a compact metal heat exchanger does the real work:

• Cold water enters and flows through narrow internal passages
• Gas burners or electric elements heat the surrounding metal
• The metal transfers that heat into the moving water in seconds

For this to stay efficient, those metal surfaces need to stay as clean as possible.

Each time you use hot water, dissolved minerals move through the heater. As the water heats up, those minerals stick to hot metal and form scale, which can:

• Reduce flow
• Cause temperature swings
• Trigger error codes and shutdowns

What Flushing a Tankless Water Heater Does

Flushing sends a descaling solution through the heater to dissolve and rinse out mineral deposits. This solution circulates through the service valves and heat exchanger, breaking down the hardened scale.

Once the flush is complete, water pathways are cleaner and smoother. This helps the unit deliver:

• Stronger and more consistent hot water flow
• More stable temperatures at faucets and showers
• Less stress on sensors, valves, and other delicate parts

By removing scale, you help your tankless heater return to its original efficiency.

General Rule of Thumb for Flushing Frequency

For average water conditions and typical household use, one full flush each year is a reasonable routine. This keeps scale from becoming thick and stubborn, while also giving a technician a chance to inspect the system.

In homes with high mineral levels or heavy hot water use, every six months often works better. A local plumber who understands neighborhood water quality can help fine-tune the timeline, but the most important step is consistency. Once a schedule is set, sticking to it keeps the heater in better condition and makes each cleaning easier.

How Water Hardness Changes Your Flushing Schedule

Water hardness is the amount of calcium and magnesium in your tap water. The harder the water, the faster scale builds up inside your tankless heater. 

• Soft or conditioned water: lighter mineral load, slower scale buildup
• Moderate hardness: steady mineral deposits over time
• Hard or very hard water: rapid scale buildup and higher stress on the heater

Santa Barbara and Ventura County are known for having hard water, which means tankless systems in the area face a heavier mineral load than many other regions. This doesn’t change how you clean your tankless water heater, but it does impact how often you’ll need to schedule flushing. Without regular flushing, scale will collect quickly inside the heat exchanger and on internal sensors. 

For many local homes, that makes a 6 to 12-month flushing schedule a smart way to protect hot water performance, keep energy use in check, and avoid preventable wear on the unit.

Usage Patterns That Wear On Your Unit Faster

Water quality is only part of the story. How your household uses hot water has a big influence on the heater’s workload. The more often the unit turns on and the more gallons that pass through it, the faster minerals have a chance to settle inside.

Homes with large families, frequent guests, or high-demand fixtures put much more strain on the system than small, low-use households. 

Clear Signs Your Tankless Water Heater Needs a Flush Now

Your heater often gives hints when it needs attention before the date on the calendar arrives. Common signs include:

• Hot water that feels weaker than it used to
• Sudden temperature swings during showers
• New or unusual sounds coming from the unit
• Error codes or warning lights on the display panel

If these signs appear, the heater may be dealing with internal buildup or other tankless hot water heater problems that a flush and inspection can help uncover.

What Happens If You Skip Flushing Your Water Heater For Years? 

When flushing is ignored for years, scale doesn’t just sit lightly on the surfaces. It packs down into a thick, crusty layer. That crust can narrow the water passages, cover the metal surfaces, and crowd the sensors inside the heater.

The heater then works harder, runs longer, and becomes more likely to overheat or shut down. Energy bills climb, comfort decreases, and parts wear out sooner than they should. In extreme cases, the cost of neglect can end in early replacement of a unit that should still have years of service left.

Protecting Your Investment Between Flushes

Maintenance doesn’t end when the hoses are removed. Simple protective steps between flushes can slow mineral buildup and keep the heater in healthier condition.

Useful measures include:

• Installing and maintaining a sediment filter on the cold water line
• Keeping any water softener adjusted and supplied with salt
• Cleaning inlet screens on the heater as the manufacturer recommends
• Keeping the area around the unit clean and easy to access

Regular visual checks for moisture, rust marks, or unusual sounds also help catch early warning signs before they affect your hot water.

Improve Equipment Lifespan & Efficiency With Water Heater Maintenance 

Regular maintenance is what turns a tankless water heater from “out of sight, out of mind” into a system you can truly count on. Clean internal passages let water move freely, so the unit reaches temperature faster. This improves energy efficiency and puts less stress on the heat exchanger, burners, and sensors. Over time, that means fewer surprises, lower energy use, and a heater that lasts closer to its full expected lifespan.

For homeowners in Santa Barbara and Ventura County, where hard water is tough on equipment, a simple maintenance plan from a trusted local plumbing company is one of the best ways to avoid recurring tankless water heater issues and keep your hot water dependable year-round.

Call Rooter Solutions for Water Heater Maintenance in Santa Barbara & Ventura County

Let Rooter Solutions set a water heater maintenance routine that fits your water quality, home, and budget. Our plumbing technicians can test hardness, inspect your tankless heater, and recommend the ideal flushing schedule to keep it running smoothly.

With professional care, clear communication, and dependable local support, you’ll reduce the risk of water heater breakdowns and enjoy comfortable hot water throughout the year. Call or contact us online today to schedule.