To
disable the filtering of a Gmail or Google Apps Email account you have
to make a Filter which will deactivate the Gmail SPAM Folder.

  To create a filter to disable or deactivate spam filter in Gmai, click on Create a filter link beside the search box (or go to Settings -> Filters -> Create a new filter).

 You add in "is:spam" in the "Has the words" text box.

You will get a warning message when you click next step.

 Next select to "Never send it to Spam" option and you are good to go.