Altitude comes first
Albuquerque sits near 5,000 feet and Santa Fe near 7,000, where thinner air means gas burners need altitude-rated equipment or adjustment. A heater burning rich leaves soot and raises carbon monoxide risk. Tankless models also lose some output at elevation, so they must be sized for it.
Licensing, water and costs
The Construction Industries Division of the Regulation and Licensing Department licenses plumbing and gas contractors statewide, while cities and counties issue permits. Most New Mexico water is moderately hard to hard, so yearly flushing helps. Expect repairs from about $150 to $600 and gas tank replacements around $1,300 to $2,800; see water heater replacement.