请教: how the depeciation affect a property's value

I am considering an offer for a property, only one thing makes me hesitating.
This house was built in 2003 and it does have some problems.In the government document, the depreciation is 20% while others with the same age in the same community is 5%. But in a neighboring community, the depreciation of properties of 16 years old is also 5% but actually the condition is worse than
this one with 20% depreciation.

Does any one know how this government record affect the future value of this house? If i remodel this house, will the depreciation stays the same?