20 USC 6339 - Carryover and waiver

(a) Limitation on carryover 
Notwithstanding section 1225 (b) of this title or any other provision of law, not more than 15 percent of the funds allocated to a local educational agency for any fiscal year under this subpart (but not including funds received through any reallocation under this subpart) may remain available for obligation by such agency for one additional fiscal year.
(b) Waiver 
A State educational agency may, once every 3 years, waive the percentage limitation in subsection (a) of this section if
(1) the agency determines that the request of a local educational agency is reasonable and necessary; or
(2) supplemental appropriations for this subpart become available.
(c) Exclusion 
The percentage limitation under subsection (a) of this section shall not apply to any local educational agency that receives less than $50,000 under this subpart for any fiscal year.