What happens at the final inspection for an ADU's MEP systems?

At final, the inspector confirms that the plumbing, electrical and mechanical systems are complete and installed as shown on the approved plans, and that the Title 24 paperwork is finished. For new ADUs, the California Energy Commission's 2025 guidance tells inspectors to verify that ECC field verifications are complete, that all compliance documents are registered, and to check the project status report. Passing final leads to the certificate of occupancy that HCD says you need before anyone lives in the unit.

Typical MEP items at final

• Electrical. Devices, cover plates and light fixtures installed; required GFCI and AFCI protection in place; smoke and carbon monoxide alarms working; panel circuits identified.
• Plumbing. Fixtures set and working, and the water heater installed with its seismic strapping and relief valve discharge.
• Mechanical. The heat pump or other equipment installed per the manufacturer's instructions and the mechanical schedule, the outdoor unit where the plans show it, and bath exhaust, kitchen exhaust and whole-house ventilation operating.

The exact checklist varies by department and project.

The Title 24 paperwork

The Energy Commission's 2025 ADU guidance lists what inspectors check on newly constructed ADUs:

• ECC verifications complete. For ADUs these include the indoor air quality ventilation fan in every case and a vented kitchen range hood, plus insulation, HVAC and duct testing when required.
• All compliance documents registered with the ECC provider registry, bearing a registration number and watermark.
• A project status report from the registry, with the ECC and overall status marked complete in order to pass inspection.
• If gas appliances are installed, electric-ready provisions in place.

The compliance documents include the certificate of compliance (CF1R), certificates of installation (CF2R) and certificates of verification (CF3R).

Certificate of occupancy

HCD's ADU Handbook says owners must obtain a certificate of occupancy from the local agency before any residential occupancy of an ADU. Los Angeles's homeowner guide says a certificate of occupancy is issued after final approval for new buildings, additions and conversions. For legalized units, Hanford requires all corrective actions to be addressed before issuing one.

Getting ready for final

1. Confirm the installed equipment matches the mechanical schedule and the Title 24 report.
2. Make sure installers have completed their CF2R forms and the ECC rater has finished testing.
3. Keep the approved plans, any approved revisions and the equipment manuals on site.

What this means for your MEP plans

Final goes more smoothly when what was installed matches what was approved. If equipment changed during construction, update the plans and energy documents before final rather than at the counter afterward. See field verification testing, Title 24 reports and equipment changes. Final inspection steps vary by city, so confirm with your building department.

Sources: energy.ca.gov, hcd.ca.gov, dbs.lacity.gov, hanfordca.gov.