Accurate List of Multifamily Buildings within Zipcode,County etc?

[Taiwo Okusaga]

Hi All,

I am researching multifamily apartment buildings under <25 units and looking to have an accurate list of these buildings within a specified zip code, county or city. i.e owner, building address, importantly - #of apartment units etc. 

Please, are there any alternative or very accurate data/methods/services apart from listsource to get such detailed information? 

Please comment and advise, any pointers are appreciated 

Thank you!!