Many materials can cause an obstructed drain. While some of them, such as tree roots, will likely require the assistance of a professional plumber, others such as hair, grease and paper can potentially be cleared with drain cleaning techniques that you can accomplish yourself. Cleaning an outdoor drain requires the proper supplies, but the results can keep the drain running optimally for an extended period of time while also saving you on plumbing and maintenance costs.
Remove the drain cover to gain unobstructed access to the drain. You can pry it off or use a manhole key on both sides to open it, depending on the type of cover.
Spray hot water down the drain with a hose to remove as much loose debris as possible. The hotter the water and the higher pressure you can achieve, the more effective it will be.
Place a plunger over the drain if it starts overflowing from the water. This is only effective if your plunger is slightly larger than the drain. Plunge the drain much like you would a clogged toilet. The suction will help remove clogs that are building up.
Pour a pot of boiling water down the drain. The heat will help dissolve oil and grease that could be building up around the drain.
Pour a drain cleaner down the outdoor drain, if your drain doesn't empty into a storm sewer, and allow it to sit in the drain for several minutes. Some cleaners require 15 minutes or more. Rinse the drain out again with hot water to rinse the cleaner out. If your drain empties into a storm sewer, avoid this step, since you'd likely be violating environmental safety laws.
Insert a drain snake or drain rod into the drain and push it down as far as possible. The act of pushing it through the drain and then pulling it back up with further reduce deposits and clogs.