What Causes a Clogged Shower Drain?

Cindy Quarters

A clogged shower drain can be very frustrating, especially if the blockage is nearly or fully complete. The water may become deep enough to flow over the sides of the shower enclosure, flooding the bathroom and possibly even soaking through the floor or running into the furnace vent. Many times such problems can be prevented with a little vigilance and some understanding of what kind of things can cause a clogged shower drain in the first place. Hair, soap, minerals, and dropped items are the most common culprits.

Lactic acid, which can help get rid of soap scum in a shower darin.
Lactic acid, which can help get rid of soap scum in a shower darin.

When a person washes his or her hair, some of it inevitably comes out and lands in the bottom of the shower. Even if the shower has a hair trap, it is more than likely that some of the hair will slip through it and find its way down into the drain pipe. Once it does, it may catch on the sides, narrowing the pipe and causing even more hair to get caught until it results in a clogged shower drain.

Shower drains may become clogged for many reasons.
Shower drains may become clogged for many reasons.

Another factor that contributes to this situation is hard water, which contains a lot of minerals such as calcium and iron. Tiny bits of these minerals stick to the sides of the drain, and over time they build up to the point that they can cause a clogged shower drain as a result. In most cases it is not the minerals alone that cause the clog, but everything that gets snagged on the places where the minerals have accumulated.

A mixture of vinegar and baking soda is a natural way to unclog a shower drain.
A mixture of vinegar and baking soda is a natural way to unclog a shower drain.

Soap scum is a very common cause for a clogged shower drain, even though, like the minerals, the soap scum itself doesn’t usually cause a complete blockage. Instead, the soap sticks to the inner sides of the drain pipe, creating rough spots and narrowing the inner diameter of the pipe, which in turn restricts its flow. Anything passing through this area has an increased likelihood of getting stuck, eventually resulting in a complete blockage of the pipe. Much of the time a clogged drain is caused by a combination of factors, and it is not unusual for minerals, hair, and soap scum to all be part of the problem.

A small toy, a bottle cap, a product wrapper, or another little object are all things that are sometimes dropped in the shower and can ultimately result in a clogged drain. Often the object will slip too far into the pipe to be retrieved. Instead of passing all the way through and out of the drain, the object will stick at a narrow place in the pipes, possibly one caused by minerals or soap scum, and will ompletely block the flow of water through the drain.

Many times a clogged shower drain can be prevented by installing a hair guard, which looks something like a tiny grate and allows water to flow through but not hair. It will also prevent dropped objects from getting into the drain. The buildup of minerals and soap scum can be reduced by pouring equal parts of baking soda, vinegar, and boiling water into the drain every few weeks to dissolve materials clinging to the pipes and keep the drain flowing freely.

A clogged shower drain may result in a foul odor.
A clogged shower drain may result in a foul odor.

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Discussion Comments


@Logicfest -- that method is effective, but it can cause some harm to pipes. The chances of your having pipes that will be hurt by bleach are slim, but be aware of the possibility.

The baking soda, vinegar and boiling water approach may not be quite as effective, but it is a lot safer on your pipes.


Another good way to keep drains flowing freely is to dump some bleach down them every couple of months. A cup of bleach will do the trick. That will eat through hair and other buildup in the drain very well. Just dump it in, leave it over night and you are all set.

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