Most states require grant applicants to provide a 40 percent non-federal match to the 319 dollars. This requirement is applied to their own 319 "grant" from U.S. EPA, and so most states pass that on.
“The Federal share of the cost of each management program implemented with Federal assistance under this subsection in any fiscal year shall not exceed 60 percent of the cost incurred by the State in implementing such management program and shall be made on condition that the non-Federal share is provided from non-Federal sources.”
(CWA, Section 319(h)(3))