Phase 1 has both electric and natural gas. I've seen homes that use gas for water heaters, forced air furnace, stoves, clothes dryers and pool heaters.
I'm all electric in phase 2 but my house was a model house for phase 3. It has a phase 3 style with the wall mount toilet, copper pipes, and PVC sewer line. Maybe they went all electric in phase 3?
I am in Phase 2. I have a gas water heater Gas stove top Gas heater Recently I installed carbon monoxide detectors.