Rough-In DWV & Water Supply Inspection Checklist (IPC/UPC)
Mandatory technical requirements and inspection checkpoints to guarantee passing municipal building inspections and avoiding re-inspection penalty fees.
📋 Critical Inspection Checkpoints
Horizontal drainage pipes 2-1/2 inches or smaller must slope 1/4 inch per foot (1/8 in. per ft for 3 to 6 in. pipes).
Drainage system must hold 10-foot head of water column or 5 PSI air pressure for 15 minutes with 0 PSI drop.
Vents must extend at least 6 inches above roofline and minimum 10 feet horizontally from openable windows.
Cleanouts required at base of each vertical waste stack, every 100 feet of horizontal run, and direction changes > 45°.
Required on fast-closing automatic valves (washing machines, dishwashers) per IPC 604.9.
❌ Top 4 Most Common Inspection Failures
- ❌ Improper slope (< 1/4 inch per foot) on 2-inch and 1.5-inch waste branches.
- ❌ Pressure drop during the 10-foot water column / 5 PSI air test.
- ❌ Improper trap-to-vent distance exceeding maximum allowable lengths.
- ❌ Missing nail plates protecting plastic water lines through studs.
💡 Re-Inspection Avoidance Protocol
Ensure pressure test gauge is pressurized and clearly visible when inspector arrives. Verify all test plugs are tight and leak-free.
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