Our new Tip 424, Heat Pump Water Heating for Commercial and Multifamily Buildings, has been posted on the SDCI Tips page. For permit applications filed beginning January 1, 2022, central domestic water heating systems in hotel and multifamily buildings must utilize heat pumps, rather than conventional gas or electric resistance systems. (In December, City Council will consider extending this requirement to include other commercial buildings with substantial water heating loads. That requirement, if approved, would take effect later in 2022.)