A cleanout with adjustable subsurface drainage capabilities which includes a first body and a second body. The first body has a first sidewall and a top access opening. The first sidewall has a plurality of circumferentially spaced and axially oriented first slots. A removable liquid impervious closure closes the top access opening. The second body has a second sidewall and a bottom access opening. The second sidewall has a plurality of circumferentially spaced and axially oriented second slots. The first body and the second body are rotatably engaged with the first sidewall and the second sidewall overlapping. A slot open flow area is provided where the first slots and the second slots overlap. Relative rotation of the first body and the second body alters the relative circumferential spacing of the first slots and the second slots placing them either out of register, partially in register or fully in register and thereby altering the width of the slot open flow area.