How To Unclog An Outdoor Drainage Pipe. Shove a hose into one end of the pipe. This may temporarily clear a clog and restore water flow, along with puddles that form on the soil.
How to unclog underground outdoor drainage pipe. One way is to pour a pot of boiling water down the drain. Feed the garden hose into the drain pipe, wrap towels around the hose and block the rest of drain to keep water from splashing out.