The relevant statute is 13 U.S.C. 223:
"Whoever, being the owner, proprietor, manager, superintendent, or agent of any hotel, apartment house, boarding or lodging house, tenement, or other building, refuses or willfully neglects, when requested by the Secretary or by any other officer or employee of the Department of Commerce or bureau or agency thereof, acting under the instructions of the Secretary, to furnish the names of the occupants of such premises, or to give free ingress thereto and egress therefrom to any duly accredited representative of such Department or bureau or agency thereof, so as to permit the collection of statistics with respect to any census provided for in subchapters I and II of chapter 5 of this title, or any survey authorized by subchapter IV or V of such chapter insofar as such survey relates to any of the subjects for which censuses are provided by such subchapters I and II, including, when relevant to the census or survey being taken or made, the proper and correct enumeration of all persons having their usual place of abode in such premises, shall be fined not more than $500."
We're only allowed to go into a residence if the resident invites us in. As far as this code goes, I'm currently dealing with an uncooperative assistant manager at an apartment complex. She said that the (off-site) manager said to not give any information except which apartments were vacant on April 1. The law says she has to provide a list of names. I have about ten units in that complex where the residents on April 1 are no longer there and a few more where I can't get anyone after four visits. This is when I normally go to the manager. All of the other managers at other apartments have given me lots of info such as names, relationships, dates of birth, Hispanic origin, and race. This lady won't.
I'm not supposed to tell people that it's required by law unless they ask. It has to be a supervisor to do that. So my CLA goes to talk to her and tells her, in a nice way, that it's required by law to provide a list of names so we can at least get a headcount. Then the assistant manager called the manager who called the Census 1-800 number and the people there told him it's not required by law. So then he calls the assistant manager who then calls my CLA and tells him that the Census is to stay out of the complex, also in violation of the law. The assistant manager seems to be ****** off at the Census Bureau. So then my CLA and I both talk to my CL who then calls the Local Census Office (LCO) and then the LCO calls the Regional Census Center (RCC) in Atlanta. Now the RCC will decide what to do and will inform the LCO and they will inform my CL who will inform me.