Sewer service charges are billed and collected annually on the San Mateo County Property Tax Roll. The cost for GCSD sewer service will be listed as an individual charge on the bill, which is mailed to the recorded property owner. The property tax bill is split into two payments, the first due by Dec. 10th and the second due by April 10th. For new buildings, the District bills for pro-rated sewer service charges from the date of the hook-up connection to the end of the fiscal year (June 30th).