Plumbing, electrical, mechanical rough-ins

What's happening

The mechanical, electrical, and plumbing trades install everything that lives inside framed walls and floors:

• Plumbing: waste, vent, water supply lines, fixture rough-ins
• Electrical: panel installed, branch circuits run, junction boxes set
• Mechanical: heat pump line set, ducts (if any), bath fans, ventilation

The trades work largely in sequence (plumbing, then electrical, then mechanical), but on a small DADU there's often overlap.

Inspections — each separate

• Plumbing rough-in (PP&D) — pressure tests, fixture rough heights, vent slopes, cleanout access.
• Electrical rough-in (PP&D) — box fill, wire size, support, working clearances at the panel.
• Mechanical rough-in (PP&D) — duct sizing, dryer vent length, bath-fan flow, line-set support.
• Insulation inspection — sometimes separate, sometimes bundled with one of the above.

All four (or three, if insulation is bundled) have to pass before drywall.

Common Portland-specific issues

• Heat pump line-set length. Mini-split installs have manufacturer-specific maximums. The typical 30 ft max gets exceeded on long house-to-DADU runs.
• Ventilation rate. Oregon requires whole-house mechanical ventilation. A bath fan timer is the cheap path; ERV/HRV is the high-quality path.
• Panel location. PGE has working-clearance and access requirements for the meter that don't always match where the electrician would prefer.