Kim Richards Down and Out in Beverly Hills Housewives

7/15/2015 9:50 AM PDT

Kim Richards won't be a full, part-time, or any time cast member on "The Real Housewives of Beverly Hills" next season ... because we've learned producers have jettisoned her from the show.

The reason is simple and pretty obvious ... Kim is struggling with substance abuse and producers think she's unreliable and poses a liability risk. 

According to our sources, Richards won't even be the ubiquitous "friend of the show."   

It's interesting ... the surviving cast members are all friends -- Kim and Brandi were the s*** stirrers of the bunch -- so you have to wonder ... where's the drama?