Pulling Comps through public records in Virginia, Maryland & DC

Hello BP,

I'm learning to analyse deals almost daily to familiarize myself with the process. The tools are awesome but I'm struggling to pull comps to determine ARV. Zillow, Trulia and such gives some information but frequently its not sufficient (ie Too few comparable home sold within the 0.5 mile radius or even the same zip code).

A recent podcast highlighted how much information can be obtained from public records. On that note, what site and or public records entity should I be looking at and how much and what kind information is available there? I'm asking specifically for central  and northern Virginia but would welcome answers for Maryland and DC as well.

 Would love to bother my realtor but due to our currenet lease we are not in a position to buy until November-January. Seems unfair to request comps daily/weekly when Im not ready to buy yet.

Appreciate all help and response