Capture the details first
Note where it’s happening, when it started, whether weather or usage seems to trigger it, and what’s already been tried — a couple of photos help the first conversation move faster.
Read the local context
Establish the build era first, because it predicts what is behind the wall better than anything else here. Mill-era and early housing carries galvanized steel that corrodes from the inside and shows as falling pressure long before it drips, over cast iron waste that fails at the hubs. Postwar housing is largely copper now old enough for pinholes. Then find out whether the house is over a crawl space, since that makes supply runs and cleanouts reachable for diagnosis -- but also means a slow leak can run a long time into a space nobody visits.
Ask what gets covered back up
Once trim, drywall, or flooring goes back, the only proof of a good job is what happened underneath it — ask about that before agreeing to anything.
Weigh full scopes against each other
Protection, access, material choice, permits, testing, cleanup, restoration, warranty terms, and change-order pricing all deserve a side-by-side look.
What official local sources add
Neither record has much to say about plumbing inside a house, and it would be padding to pretend otherwise. Where they do reach the trade is at the property line and below it. Work on a sewer lateral or a water service line is excavation in the right-of-way or across a recorded easement, and the stormwater department's mapped drainage information is exactly what tells you what else is buried along that route. There is also a connection worth naming: a downspout or footing drain improperly tied into a sanitary line is a real problem in older textile-era housing, and it is a stormwater issue and a plumbing issue at the same time.
Sources were reviewed June 20, 2026. Confirm parcel-specific flood zones, historic-district status, permits, and current requirements with the relevant authority before authorizing work.