20 CFR § 416.2040 - Limitations on eligibility.
Notwithstanding any other provision of this subpart, the eligibility of an individual (or couple) for optional State supplementary payments administered by the Federal Government in accordance with this subpart shall be limited as follows:
(a) Inmate of public institution. A person who is a resident in a public institution for a month, is ineligible for a Federal benefit for that month under the provision of § 416.211(a), and does not meet the requirements for any of the exceptions in § 416.211 (b), (c), or (d), or § 416.212, also shall be ineligible for a federally administered State supplementary payment for that month.
(b) Ineligible persons. No person who is ineligible for a Federal benefit for any month under sections 1611(e)(1)(A), (2), (3), or (f) of the Act (failure to file; refuses treatment for drug addiction or alcoholism; outside the United States) or other reasons (other than the amount of income) shall be eligible for such State supplementation for such month.
(c) Recipient eligible for benefits under § 416.212. A recipient who is institutionalized and is eligible for either benefit payable under § 416.212 for a month or months may also receive federally administered State supplementation for that month. Additionally, a recipient who would be eligible for benefits under § 416.212 but for countable income which reduces his or her Federal SSI benefit to zero, may still be eligible to receive federally administered State supplementation.