Start with the affected taps, hot-or-cold pattern, public notices, and official water information.
The short answer
Do not identify safety or cause from color, taste, or odor alone. Record whether the change occurs on cold water, hot water, one fixture, or throughout the property. Check DWWD notices and contact the district or appropriate public-health source for water-supply and testing questions.
What to notice
Separate hot water from cold
A change only on hot water can focus attention differently from a cold-water change at every fixture. Let the public water supplier or qualified provider direct any sampling or flushing plan. Do not run large volumes, remove an aerator, or change a filter if an official advisory gives different instructions.
Preserve useful context
Note the first date, duration, nearby work, vacancy, filter or treatment equipment, and recent heater service. A clear glass observation can be described without claiming a contaminant. Photographs do not measure lead, bacteria, or chemical quality. Use a certified laboratory when official guidance calls for testing.
Keep utility and premise plumbing questions distinct
The district can address public supply and service information; a qualified provider can inspect property plumbing. Ownership boundaries and service-line material require records, not assumption. If only one outlet is affected, the fixture remains relevant, but that pattern still does not prove the cause.
One useful question
Can a plumber tell if water contains lead by looking at it?
No. MassDEP explains that lead usually cannot be seen, tasted, or smelled in drinking water. Use the official service-line information and certified testing guidance. Do not infer lead from color, property age, or a fixture stain.