Oakbrook I Apartments Oakbrook I Apartments is a HUD Apartment. HUD residents usually pay 30% of their gross income for rent. The rent amount, less approved HUD deductions such as medical and child care expenses, and other allowances, includes a utility allowance. HUD Residents also may choose to pay what is known as flat rent. The HACC works with applicants to determine which rent arrangement is best for them. Oakbrook I Apartments is a senior low income housing apartment subsidized by the federal governments HUD (Housing and Urban Development Division). Contact Oakbrook I Apartments for complete details on the current vacancies and housing applications.