Compare hot and cold
Record whether the odor appears in cold water too, at every fixture, after stagnation or only at one bathroom. This observation helps the provider locate the affected part of the system. It does not identify a contaminant or prove that the source water is safe.
Define the diagnostic visit
Ask who will inspect the heater, plumbing and source as appropriate. A whole-house treatment quote should explain how it addresses the observed location of the problem. Do not alter heater components or chemical treatment without the relevant qualified professional and manufacturer guidance.
Check the same conditions again
After service, compare the same fixtures and conditions that produced the complaint. Keep any laboratory result separate from a smell-based observation. If the concern also appears in untreated cold water, request the source-specific assessment rather than assuming the first repair covered every line.
House, additional buildings and private-well boundaries
For a Wellington request, identify the supply serving each building before discussing equipment. A household connected to municipal water differs from a house on a private well, and a barn or irrigation line may be a separate scope. List the affected outlets and the demand the proposal is expected to serve. Do not apply a domestic equipment recommendation to animal-care or other specialist uses without the relevant professional guidance. A written line map helps the provider assess the correct project.