As far as estimating rehab costs, there's a book called Estimating rehab Costs (ha) published by bigger pockets.

@Kevin ChanHa ha ya true.

HAha ha   Sadly the joke is on you, when you allow a government to make choices for you, you no longer are free. 

(Ha Ha) if you have anywhere the same experience I did, recruiters will show up to buy you lunch & pitch to you to come work with their company.

@Steven Wilson ha!

Because if its for 2 water heaters its a decent price, really bad if its for one ha. 

Also don't panic if the first payment gets messed up - the HA will fix it and pay you in arrears (this shouldn't be a problem but just in case).If you haven't already, I'd recommend requesting the most recent "notice of change" or annual recertification for the S8 tenant (a document that comes from the Housing Authority) that lays out how much the tenant pays and how much the HA pays. 

This is a document from the Housing Authority that lays out how much the tenant pays and how much the HA pays. 

Contact the HA to confirm what paperwork they need and if there is a timeframe for them and the tenant.

They won't take anyone in their offices anymore even if we wanted to schedule an appointment.I obviously know nothing about your HA but I work with 2 here and the name of the game when it comes to rent increases is to Shoot The Moon.