Sorry I don't have any insight into the NoVA Section 8 market but I know the approved rents in the District are extremely high but I do have a question that will hopefully help you out as well...Does the DC Housing Authority do a market analysis on comparable rentals in the area before they agree to pay the amount listed on the website or are the rent amounts listed on the DC Housing Authority what investors are typically getting? 

@David Shapira House hacking in Boston can be great but its more of an appreciation play then cashflow when you move out. 

Section 8 recipients can pay the difference on rent, but it is up to the housing authority to approve the difference based on their declared income. 

(Owner-occupied)You can play with these on your county's tax assessor sight, estimating real property taxes for occupied/rental.If you want to get into the SFH space, and be competitive, I think your best bet is to invest in properties whose assessed value is sub $75k-$90k.

@Robert Vanecek not to play the devil's advocate, but what will the tenant do when a potential buyer brings their family through? 

Respond by returning the bill, along with a short and professional letter that says you did not authorize the work and that you already lined someone up to do the work for $300.

I'd say make sure you have at least a 10% contingency budget allowed for any unseen freeze damage to play it safe.

Non-qualified use comes into play when the property in question was first a rental before converting it into a personal residence.

More generally, how much does the building play into the appreciation of the condo?

Anything in a coastal market is more of an appreciation plan than a cash flow play.