How to Cap a Water Drain to a Sump

Unplug the sump pump's power cord or turn off the dedicated breaker that supplies electricity to the pump; allowing the pump to operate while capped might burnout the pump's motor. Follow the pump's discharge drain pipe from the sump well to its exit point on the wall. Note the rough location of pipe's exit.

Move to your home's exterior and locate the discharge pipe; while some pipes exit above ground, others run below grade. Use a shovel to dig a trench and locate the pipe, if necessary. If the pipe empties into a storm drain, locate and remove the drain's grate to find the discharge pipe's end.

Determine the type and size of the pipe with a tape measure or by reading specifications printed on the pipe's exterior wall; rigid PVC pipes include text that specifies pipe diameter and schedule. Select a cap that matches your pipe's size and type.

Wipe the end of the pipe with a clean rag to remove grit, moisture and grease. To install a PVC pipe cap, apply PVC primer to the interior of the cap and the exterior of the pipe's end. While the primer remains wet, apply a layer of PVC cement over the primer, insert the cap onto the pipe and twist the cap roughly one-quarter to one-half rotation. Hold the cap in position for roughly 30 seconds.

Install a hose-thread pipe cap by pressing the cap's threads against the discharge pipe's threads and twisting the cap clockwise until its gasket seats against the discharge hose's end. Attach flexible pipe caps by slipping the cap over the pipe's end and tightening the cap's clamp screw clockwise with a nut driver or slotted screwdriver.