Production sources tell TMZ ... the bigwigs have changed the policy of limiting alcohol consumption ... the spigot is wide open and the cast is taking full advantage. Omarosa, James Maslow, Brandi Glanville, Ross Mathews and the other houseguests have partaken every night since January 31 when they entered the house.

The buzz we're hearing ... producers want Omarosa to spill the beans on her tenure in the White House. She's already started, turning on Trump ... saying everyone should be worried about the Prez, saying things in the W.H. are "so bad."

The show used to be stingy in the alcohol department ... it was typical contestants would share 2 bottles of wine and a few 6-packs each night, but producers are worried celebrities play things closer to the vest than the average Joe, so a little alcohol -- or a lot -- always does the trick.