It’s most likely the State’s Energy efficiency code to be applicable with a gut remodel where you’re moving walls and changing the layout. These are considered “alterations.” A “rip-and-replace” project maintains the existing footprint of the bathroom. It may not trigger Title 24 requirements if the project doesn’t change the energy usage. However, changing the size of windows and doors does fall under Title 24, as does changing the water heater and the rest of the plumbing system. Text or call Modern General Contractor for a bathroom remodel project in Santa Monica.