California Code, Streets and Highways Code - SHC § 18193

Upon such entire or partial abandonment, all money collected for any improvements which have not been made, which money has not been paid therefor, shall be repaid to the owners of the parcels in the abandoned portion as shown on the last equalized assessment roll preceding the date of partial abandonment;  provided, however, that if a district is reinstated concurrently with a partial abandonment, such money shall not be repaid but shall be credited against the cost of the improvements of the reinstated district.