Preserve the useful detail
Use only fixtures that cannot overflow. Note the lowest affected opening, sequence, recurrence, recent work, and available cleanouts.
The decision on display
Do not transfer the hazard
Stop adding water when it rises elsewhere. Avoid chemical products that can injure people, damage material, or complicate service.
Make the proposed work comparable
Define access, protection, method, included attempts, stopping conditions, cleanup, flow test, and evidence for camera work or repair.
CURRENT PRIMARY SOURCE