I forbid all business activity and specifically childcare - - I my reading comprehension is just fine thank you. 

.:- https://www.biggerpockets.com/forums/88/topics/244...Common themes seem to be: fighting City Hall re: tax assessments?

Nicks is by far the most comprehensive . 

I found this the other day in Tacoma wa http://www.zillow.com/homedetails/7611-9th-Avenue-...I used the calculator of BP and took my best assessment of the property.

My first deal was very similar I paid considerably less but had I better assessed my number I would have offer $4,000 less.... not much on your first it all adds up.

To echo Chris above, and in broad strokes, comb your records and look at capital projects for upping your basis, and they likely would have come in the form of an assessment, like for something major such as a new roof, new siding, etc or something you paid for the interior, then study up how to adjust your basis or see an accountant..

Interesting valuation you have, the $600 part sounds like a tax assessment or an old appraisal, I haven't seen an investor on BP reach a valuation that comes in at $100 above a round number.Tax assessments are for tax purposes, not an investment or market valuation.If that is a true value, there isn't enough of a spread to make this a deal, by the time you have closing costs you'll probably be at market value, you could go over if that valuation is off just a few % points. 

It is entirely possible the tax assessed value has no correlation to the market value of the home.  

If it is just for your own usage just make sure it is permitted to do so then do what you need to do and do not register it with the city until you are ready to sell it so you can avoid a higher taxation and re-assessment of taxes. 

A judge would not be at all interested in listening to you spit out arcane legal theories in that forum.Try reading for comprehension next time.