Preserve the useful detail
Record which fixture changes another, sudden or gradual onset, bowl movement, sound, and accessible cleanout without repeating overflow tests.
The decision on display
Do not transfer the hazard
Stop use when one fixture raises water elsewhere. Keep people from wastewater and do not dismantle concealed traps.
Make the proposed work comparable
Name fixture access, clearing method, retrieval, camera limits, cleanup, reassembly, leak testing, and multi-fixture flow testing.
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