There are usually two basic ways to unclog a shower drain: either fish the clog out yourself, be it through a manual extractor or a plunger, or flush the clog further through the drain such that water can again pass through. Which method you choose is largely a matter of how your shower is constructed, but it also depends on how the clog formed and what it is made of. Most of the time, shower drains get stopped up because of soap scum or trapped hair. This sort of debris is relatively easy to fish out with even the most basic technology. More complex clogs, particularly those caused by calcium buildup in the pipes, often need some sort of in-pipe treatment.
Most shower drains are fitted with a grate that is designed to catch hair and debris. Not everything gets caught, however, and over time, rogue detritus can cause plumbing concerns. This sort of clog is often easy to fix, as it is usually sitting just near the opening of the pipe.
The process needed to unclog a shower drain in this instance is usually quite simple. First, you will need to unscrew the grate covering. In a bathtub shower, unscrew the drain cover or stopper. Once this is completed, you will need to choose your tool.
Many of the shallowest clogs can be removed with as little as an unbent metal coat hanger. Use the wire as a sort of hook for the hair and debris, pulling it up slowly to keep from breaking the clog or losing portions of it back down the drain. Plumbers' tools like snake drains, coat augers, and zip lines may be required for more aggressive clogs. All of these are usually available at home improvement stores.
You can also sometimes find success by using a plunger to unclog a shower drain. Any standard toilet plunger will do, so long as it completely covers the drain opening. If you are working with a tub drain, you will need to seal the overflow valve in order to ensure a good seal. A shower stall does not usually have such a valve.
Position the plunger over the opening, seal it, and plunge repeatedly until the clog comes free. Depending on how deep it is, you may still need to fish the clog out manually. It will usually come free relatively easily once the drain has been plunged, however.
Another way to unclog a shower drain involves bubbling the clog to the surface with a baking soda and vinegar solution. When combined, these two elements react fiercely as the acid in the vinegar breaks down the sodium bicarbonate in the baking soda. Pouring a bit of baking soda down the drain followed by white distilled vinegar will often cause clogs to break free and bubble to the surface.
For optimal results, seal the drain with a washcloth or small towel immediately after pouring the elements in. This will force them further into the drain, rather than enabling them to bubble back into the shower stall. After about a half hour has passed, flush the drain with boiling water. Baking soda and vinegar are both non-toxic and present no risks to your pipes or to the environment. The water simply acts as a sterilizing rinse.
This same combination can sometimes also help dissolve lime and calcium buildup, as well as other non-organic clogs. The pouring and sealing process must often be repeated multiple times in order to see results, however. In some cases, use of a commercial drain opener may be the best bet. Plumbers usually discourage regular use of chemical-based solutions, as extended exposure can degrade pipes over time, and the chemicals can also be hazardous if spilled or breathed in. For particularly stubborn clogs, it is usually a good idea to consult a professional before attempting to unclog a shower drain with harsh chemicals.