Document the condition
Write down the location, when it started, any link to weather, and how it's progressed. Photos and basic measurements help the first conversation move faster.
Read the local context
Before this is quoted, get underneath and establish what is actually there. In the mill-era housing these spaces are shallow and tight enough that access alone frequently sets the limit on what can be done, so the depth, the state of the ground cover and whether the ductwork is intact all matter more than any product choice. Then go outside and look at where the lot falls and where the downspouts end, because on rolling ground the water usually arrives at one wall, and sealing a space before that is handled rarely lasts.
Ask what will be hidden
Plan around the actual failure points: bulk water entry, ponding under the house, an inspection gap for termite treatment, liner seams and attachment, sealed rim joists, right-sized equipment, and whatever the joists and sills look like today. Everything gets covered up once the liner's in, so the written scope needs to spell out what prep and checks happened first.
Compare complete scopes
Look for a scope that names protection measures, access plan, materials, permits, testing, cleanup, restoration, exclusions, warranties, and change-order pricing.
What official local sources add
The stormwater side is the part that reaches this work, because sealing a crawl space almost always depends on exterior drainage being corrected first. Where water is routed once it leaves the foundation is the regulated question, and on the rolling lots common here that route usually crosses a neighboring property or feeds a mapped drainage path -- so the parcel's drainage conditions are worth establishing before a liner is priced rather than after it fails. Historic-district information matters only where below-grade work produces a visible change at grade, such as a new exterior access or a regraded front slope on a designated property.
Reviewed June 2026. Parcel-specific flood status, historic-district standing, permit rules, and current requirements should be confirmed with the relevant authority before work begins.