SPU publishes a public-main investigation route when a contractor suspects mainline or connection involvement.
DOWNTOWN SEATTLE / GUIDE
Sewer Backup Event Record
Record who made each finding and the segment assessed.
PRACTICAL GUIDE
Write the event chronology
Keep exposure, affected spaces, fixtures, private findings, SPU work-order information, damage, cleanup, and invoices on one timeline.
Do not treat a public response as proof about private piping or cleanup completeness.
Keep public and private findings together
Record the first and lowest wastewater return point, affected units and floors, time, weather, ordinary fixture activity, prior events, street observations, building contacts, private assessment, camera media, cleanup, and any SPU work-order reference. Avoid assigning cause or ownership in the event log.
Preserve photographs and receipts without delaying safe professional cleanup.