My drain pipe sits 19-19.5" above the floor--pretty high. I am hoping to install a deep under mount sink but I know that my disposal outlet pipe needs to be above the main drain. I have done the math (we have 38" cabinets and I bought a disposal with the outlet pipe only 6" below the sink) and it will sit @ 20.5" above the ground--about 1" above the main drain. Is this adequate slope to keep the disposal draining properly? Does the minimum of .25"/ft slope apply to this as well? I can't find any information about how much higher the disposal outlet should be, only that it should be higher...
Proper slope between disposal outlet and main drain
