Proof with a PO Box address is not acceptable (except for NYS income tax returns). Your proof must reflect an actual physical address.Proof with a P0 Box address in not acceptable (except for NYS income tax returns). • Mail: Suffolk County DSS – Child Care Bureau, P.O. Box 18100, Hauppauge, NY 11788-8900. Proof of residency must show applicant's address (not P.O. Box or in care of a third party) and include the applicant's name. Submit the affidavit to your county with two (2) of the following documents as proof of residency. Suffolk county asks for proof of residence in the form of a utility bill, tax bill, or voter registration card. Fill out the Residency Affidavit(s). 2. Have your signature(s) notarized. 3.