A proper drain-and-clean is preventive maintenance wearing work gloves: purge the lines, flush the mineral, rebuild the chemistry for the water you actually have.
Around here a drain is not just fresh water — it is the one chance to undo what dissolved rock has been doing since the last one. Our service runs the full sequence: a purge product through the old water to strip biofilm from the plumbing, full drain, mineral flush through the heater path, filters soaked or replaced, then a refill balanced against a hardness test of your actual tap, not a statewide average.

Done on a schedule, this one visit is why our regulars almost never meet our heater department. Skipped for a year or two, the same minerals show up later wearing a much bigger invoice.
Filters past saving or chemistry set for softer water than yours. Both are fixable on the spot.
The visible edge of what is also coating the element and the jet passages.
Biofilm in the lines. It laughs at sanitizer and surrenders to a purge.
Mineral baked into the pleats. Rotation or replacement — rinsing is over.
Real faults, real fixes — the paperwork version, minus the addresses.
Filters were done — mineral baked into the pleats. New set plus a line purge; the chemistry finally held.
Biofilm in the plumbing. Purge product, full drain, refill — gone.
Describe the symptom and the brand — the diagnosis starts on the phone and finishes with one written number.