APA's Publication Manual, section 8.03, mentions 1 inch margins as a guideline, not a rule.
To be specific, they say:
“Leave uniform margins of at least 1 in. (2.54 cm) at the top, bottom, left and right of every page” (p. 229). We recommend that you use the Page Layout -- Margins function in Word to set up the 1 inch margins:
For more information on APA Formatting, view the Formatting page of the APA Guide below: