Right now 283 and Div15 also house (supposedly) Reserve Engine 515 and a decon support unit (Decon 283).
There have been multiple other units there in the past including:
Ladder 120 (1995-1996)
Ladder 174 (1994)
Division 7 (1995)
Ambulance 2/Mobile Medical 2 (now RAC2) (1977-1990)
Squad 4 (1973-1976)
yep, they are doing a few houses over major work in some. I also know that they are redoing the whole floor of E309 L159 and adding an extenison to the side of the house to cover the CPC and Highway rig. E309 will be going to E321 and L159 is going to E323 as of now. I think the work is suppose to start in the fall and last for about a year.