Most Lewisville homes inside the utility service area get soft water from Winston-Salem/Forsyth County Utilities, which is kind to a tankless water heater's heat exchanger. When an existing unit acts up, the choice between repair and replacement usually comes down to its age and what failed. Call the number on this page to be connected with a local plumber in Lewisville.

Lewisville conditions
Lewisville gets water and sewer service through an agreement with the City-County Utilities Commission, the body behind Winston-Salem/Forsyth County Utilities. The Town's Rural Overlay means not every area has public lines, and some homes on the rural-zoned edges may be on private wells. For homes on the public system, the 2025 water quality report lists average hardness at 17.5 ppm, which is soft, and chlorine disinfection.
Census survey figures put Lewisville's median build year at 1987, with about 35% of homes built before 1980. Many of the earliest tankless units in the area went into houses like these during remodels, and some are now old enough that owners face a repair-or-replace decision. Permits are handled by the joint Winston-Salem/Forsyth County Inspections Division, which lists Lewisville among the towns it serves. Forsyth County is entirely within Piedmont Natural Gas territory, though mains don't reach every road.
Repair or replace
| Situation | Usually repair | Usually replace |
|---|---|---|
| Ignition or flame sensor fault | Unit under 12 years old and parts available | Repeated failures on an older unit |
| Low flow or temperature swings | Clogged inlet screen or scale that flushing clears | Unit undersized for the household |
| Water leaking inside the cabinet | Loose fitting or failed valve | Cracked or corroded heat exchanger |
| Venting error | Blocked or disconnected vent pipe | Vent system that doesn't match current code |
Signs to call
- The display shows the same fault code more than once
- Hot water turns lukewarm when two fixtures run
- The unit is noisy, smells of exhaust or the vent outside is damaged
- It has been years since the last flush or service
Seasonal notes
Winter is when tankless problems show up. Colder incoming water forces the unit to work harder, so a heater that was borderline in summer may fall short in January. Exterior-mounted units and vents also need freeze protection, and the unit's own freeze protection relies on power. Scheduling a flush in the fall gives the unit its best chance through the cold months. If that visit shows the heater is near the end of its life, autumn is also the easier time to plan a replacement, since waiting for a failure usually means a cold morning and fewer choices about which unit goes in and where it's mounted.
Tankless Water Heaters questions in Lewisville
My tankless unit shows an error code. Is it worth repairing?
How long should a tankless water heater last?
Does well water change how a tankless unit should be cared for?
Why does my tankless heater deliver less hot water in winter?
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