The SQ Footage Total Finished - this may be the one that is input by the listing agent - I am not sure exactly how Trulia draws their data.
The important thing to remember is to take square footage with a grain of salt - don't base decisions solely on what either of these numbers says. There are many different nuances and rules for the calculation of square footage and everyone does it differently. The best thing to do is, if it's in the ballpark, take a look at the space and see how it feels.
Let me know if I can show you any of those condos - I am VERY familiar with Reston condos.
If you are trying to do a square footage comparison for pricing..I would not go too deep into it as there are certainly other variables with greater impact on price than square footage. Hope this helps and if you need some professional guidance feel free to contact me.
Erik J. Weisskopf, ABR,CDPE,CRS,GRI
Condominiums can be town houses and even single family homes - very different from Fee Simple form of ownership for a typical townhome or single family home.
By the way, in Northern Virginia, there are at least two condominium single family detached home developments, and many town house developments.
You may also want to keep in mind that some builders count the square footage of 2 story Entry Foyers and Family Rooms TWICE ( as the main floor and then the upper level, even though the upper level is not an actual living space) and report it as such in the tax records.
A better way is to measure the rooms (especially bedrooms) and compare with other floor plans - furniture should fit comfortably, assuming the correct use of the rooms.
One thing to note right off the bat is the tax living area is auto filled by the system from the public tax record, but the square footage total finished is filled in by the Realtor therefore it is not as exact. These numbers are typically similar but sometimes an agent knows from the Owner that the tax records are wrong (Government wrong what a shock) and enters the correct info in the system. You will also see many times square footage total as zero as some agents are concerned about being accused of misrepresenting it so they just put nothing.
Hope this helps. Are you currently working with a Realtors in your search. Perhaps he/she can better explain the differences in a specific listing. If not forward me the address of an actual listing and I will see what I can find out.
Keep in mind, often times the tax records are incorrect, but then again so are listing that are entered by the listing agent.
If you have any specific examples, feel free to reply or send me an email at firstname.lastname@example.org and I'd be happy to do some due diligence for you. I live and work in Reston.
All the best,
Town and Country Group