1. Note what’s actually happening
Where it shows up, when it started, and whether it’s constant or comes and goes — write it down before you call anyone.
2. Walk the whole system, not just the symptom
Pressure, drainage, venting, pipe material, and what’s been touched before all factor into an accurate read of the problem.
3. Put the scope in writing
Materials, access, permits, testing, cleanup, and what happens if something unexpected turns up should all be spelled out before work starts.
4. Line up more than one provider
Look past the bottom-line number to how each one explains their reasoning and where their responsibility ends.
5. Check the finish, not just the fix
Confirm testing was done, the area was cleaned up, and you know what’s still your responsibility to maintain.