There are 21 episodes in season four of The Real Housewives of Potomac and episode 20 had the most viewers.
21 20 1.18 1.16 0.96 1.11 0.89 1.04 0.91 1.07 0.96 1.15 1.07 1.02 1.07 1.10 1.04 1.09 1.01 0.90 1.17 1.12 1.11 
