Drain covers for pools and spas must comply with the Virginia Graeme Baker Pool and Spa Safety Act Regulations. This mandatory federal consumer product safety rule is found at: 16 CFR Part 1450.
The standard requires that each swimming pool or spa drain cover manufactured, distributed, or entered into commerce in the United States conform to the entrapment protection standards of ANSI/APSP/ICC 16-2017, American National Standard For Suction Outlet Fitting Assemblies (SOFA) For Use In Pools, Spas And Hot Tubs. This standard is available for purchase from ANSI by following the link above.
Section 2 of a GCC requires a list of applicable citations for the product being certified. The citation for pool and spa drain covers is: 16 CFR Part 1450.
For more information, see this letter from the Office of Compliance on Pool and Spa Drain Cover Safety.