Tankless Water Heater Maintenance Guide for Maryland Homeowners

Why Maintenance Matters More in Southern Maryland

Tankless water heaters are significantly more sensitive to water quality than traditional tank heaters. The heat exchanger — the component that heats water on demand — has narrow passages that scale up quickly when exposed to hard water. In Southern Maryland, where well water hardness commonly runs 12–25 GPG, an unmaintained tankless unit can lose 25–30% of its efficiency within 2–3 years and fail completely within 5–7 years instead of the expected 15–20.

Annual Descaling: The Most Important Maintenance Task

Descaling (also called flushing or deliming) removes calcium and mineral deposits from the heat exchanger. The process involves circulating a food-grade descaling solution (typically white vinegar or a commercial descaler) through the unit using a submersible pump and hoses connected to the service ports.

For Southern Maryland well water owners, we recommend descaling annually — or every 6 months if your water hardness is above 15 GPG and you don't have a water softener. With a properly sized water softener, you can extend the interval to every 2–3 years.

Complete Maintenance Checklist

• Descale the heat exchanger: Annually (or per hardness schedule above)
• Clean the inlet filter screen: Annually — removes sediment that restricts flow
• Check and clean the air intake filter: Annually for gas units — affects combustion efficiency
• Inspect the venting system: Annually — check for blockages, corrosion, or disconnected sections
• Test the pressure relief valve: Annually — lift the lever briefly to confirm it opens and closes
• Check for error codes: Monthly — most units display codes for common issues
• Inspect gas connections: Annually — check for leaks with soapy water or a gas detector
• Flush the system: If unit has been winterized or unused for extended period

Signs Your Tankless Unit Needs Service

Don't wait for a complete failure. These signs indicate your tankless water heater needs attention:

• Error codes on the display panel
• Reduced hot water flow rate
• Water temperature fluctuating during use
• Unit takes longer to reach temperature
• Unusual noises (popping, rumbling) during operation
• Visible scale or mineral deposits around connections
• Higher gas or electric bills without increased usage

The Water Softener Solution

The single best thing you can do for a tankless water heater in Southern Maryland is install a water softener before it. Soft water eliminates scale buildup entirely, extends the service interval to every 3–5 years, and can add 5–10 years to the life of the unit. The cost of a water softener (contact us for a free estimate installed) is typically recovered in reduced maintenance costs and extended equipment life within 3–5 years.