Rules on displacing Tenants during unit repairs

[Ames Foley]

I have a situation where an underground hot water line broke and I need to replace or run new lines. Until complete there is no hot water in the unit. We decided to run new lines. The issue is that the unit is occupied.  We lined up a temporary unit to move them to but it is 15 minutes from the current unit (friends open unit).  The occupant declined and said they would stay out of the way.  This is my first time dealing with this situation.  Is there any issues with not moving the tenants?  legal or other?  Anyone else have to deal with this?  I have read about rehabs but not repairs.  Are there any significant differences beyond must do vs wanting to do?  thanks,