<prompt> Most impoant pre-requisite in sanitary latrine is :Squatting plate or slabWater sealSmooth slope of panAdequate drainage  <response>: Water seal Water seal: The most impoant pa in a sanitary latrine is the water seal. The water seal is the distance between the level of water in the trap the lowest point in the concave upper surface of the trap It has two impoant functions It prevents access by flies It prevents escapes of odors foul gases The depth of water seal in the RCA latrine is 2 cm 