Water that persists when indoor fixtures are isolated may involve an exterior branch or the segment before the house master.
California's C-36 plumbing classification includes water piping on the property-owner side of the utility meter. That classification does not decide who owns an individual fitting or authorize anyone to operate district equipment. Confirm the local boundary with IWVWD when needed.
Keep this boundary: A wet area is not enough to assign ownership or approve excavation. Utility locating and jurisdictional requirements still apply.