Water heater sediment buildup degrades efficiency invisibly for years because homeowners have no way to inspect tank interiors

Mineral sediment (primarily calcium carbonate) accumulates at the bottom of tank water heaters at a rate determined by local water hardness, but homeowners cannot see inside the sealed tank — so sediment builds a progressively thicker insulating layer between the burner and the water for years until efficiency drops noticeably or the tank fails catastrophically. Why it matters: the sediment layer forces the burner to run longer to heat water through the insulation, so energy bills increase 10-30% without any visible cause, so homeowners attribute rising costs to utility rate increases rather than their own equipment, so the tank overheats at the sediment contact point and accelerates steel corrosion from below, so the tank develops pinhole leaks or catastrophic ruptures that dump 40-80 gallons of water onto basement or utility room floors. The structural root cause is that tank water heaters are sealed steel cylinders with no inspection port, no sediment depth indicator, and no efficiency monitor — the only maintenance interface is a drain valve at the bottom that most homeowners do not know exists and that frequently clogs with the very sediment it is supposed to flush.