Certain federal regulations are applicable to your ARPA award, such as Uniform Guidance (2 CFR Part 200). Section 200.425 discusses audit services and states: “A reasonably proportionate share of the costs of audits required by, and performed in accordance with, the Single Audit Act Amendments of 1996 (31 U.S.C. 7501-7507), as implemented by requirements of this part, are allowable.” If you expended funds from multiple federal grant programs in a fiscal year, each program would pay a proportionate share of the cost of the Single Audit.