 altering the default value of an exposed filter modifying default values of a views exposed form is tricky because fapi was not designed to work with get forms one consequence is that it often can t tell if textfields there are others were submitted or not as a consequence it always thinks the value was submitted even if it was not to fix that views modifies formstate input identifier with the default value if formstate input identifier was not set in order to modify the default value in an alter you need to do this php if empty formstate view exposedinput identifier formstate input identifier defaultvalue where identifier is the particular filter for which you want to change the default value and defaultvalue is the new default value you want to set if you use a hookformformidalter or hookformalter you can modify exposed filters on the fly based on information that is external to views for example i modified the exposed filter of a form to set a taxonomy term id based on the user s geoip to do this i used the following function where geoipredirectgettid loads the relevant term id based on the user s current ipaddress php function modulenameformviewsexposedformalter form formstate if strpos form id volunteerdirectory false citytid geoipredirectgettid if isnumeric citytid citytid 7660 if empty formstate view exposedinput tid formstate input tid citytid  