2009 IRC Section G2415.1 (IFGC 404.1) “Piping …. shall not extend through any townhouse unit other than the unit served by such piping.”

 

What would the reason be for this and why only townhouses VS apartments/condos or commercial tenants?  This restriction does not apply to any other utility (electric, water, cable).

What do you see in your jurisdiction?
 
What licenses and permits would be required in your jurisdiction? Thanks, Rich