Because this energy is generated off-site, you should enter it as “District Hot Water.” Portfolio Manager assesses the energy efficiency of a building, not its utility's efficiency. You do not get credit for the relative efficiency (or inefficiency) of your energy supplier. The ENERGY STAR score and other metrics are based on the total amount of energy consumed by a property. If you’ve got an on-site geothermal system, the answer is different.
This is consistent with how Portfolio Manager works for properties who get electricity from utilities who use wind or solar energy. All purchased electricity is counted “grid” electricity and get the standard national electric grid factor.
However, the property who is purchasing electricity from wind/solar will get credit in their Emissions. Currently, this credit is only available for electricity, but if we gather enough data about other renewable forms of energy (district hot water from geothermal), then we can look into offering a credit in Emissions to these properties.