Surface water decides whether a liner holds
Encapsulation is not permit-heavy, so the stormwater record matters indirectly: a sealed crawlspace over ground that keeps taking surface water will not hold conditions. On karst terrain, where water disappears into the ground rather than running off, drainage behaves less predictably than a slope map suggests. Establishing where water reaches the crawlspace comes before choosing what to line it with.
Official sources
Find the water before sealing the space
Citywide guidance cannot tell you where water enters your crawlspace, whether the existing barrier is intact, or how humid the space actually runs. Establish the source and take readings before any liner is specified.
Research date
Sources reviewed 2026-07-20. External requirements and maps can change.