It will be a 2-5 year project depending on absorption.

Then there are absorption heat-pumps, but I've yet to see/study a residential installation.

All of these things along with unit mix and being multi level or one one level and location can affect what rent rates you will get and how long to lease up the new building (absorption).For instance usually a 200 to 300 unit apartment building is constructed in phases and takes a few years to fill up.

The ones that are stated over and over seem to be job growth, population growth and absorption.

I am a Commercial Agent who has very capable residential agents.Showing positive absorption on the commercial side (office/retail/industrial)Residential market is stable with a large number or foreclosure and bank owned properties.

This analysis includes SFR's and MFR's.On the other hand, for the lower socioeconomic blue collar rentals (B class), I see rental rates will remain the same or a slight increase as we are still in the absorption period where vacant units are being converted to rentals.

Also, with short term rates and their borrowing costs near zero, these entities seem to face minimal financial consequences from slowing the process to ease the absorption of the overhang (good for incumbents, I'd think).I know the cheap funding cost is encouraging local banks to hold out more aggressively when selling their REOs.

It will be time to start doing absorption studies.

I'm guessing in 4 years Cap rates will go back down again after some of the absorption for new units are complete. 

Would the drainage requirements be mitigated by making the parking lot from pervious pavement/asphalt and the installation of a green roof(which would contribute to stormwater absorption?)