There's a debate many have very strong opinions on - whether or not to brush your teeth in the shower. Some say it's gross, while others say it saves water and time (hey, even Michael Phelps does it!). The Wall Street Journal just published an article on the topic, weighing both sides of the argument.

How many people are doing it? According to the article, "A 2014 survey by Delta Dental Plans Association, a dental-insurance provider, found 4% of Americans, or about 13 million people, say they brush most frequently in the shower.

Is it harmful? No, but it may not be as effective. If the toothbrush doesn't stay in the shower, since moist environments breed bacteria, it's not harmful. But a dentist quoted in the article "advises his patients with poor dental health not to brush in the shower partly because it could lead to flaws in brushing technique".

Does it save water? Probably not. As AWWA states in the article, shower heads use 2.5 - 3.5 gallons a minute and sinks use 1 - 3 gallons a minute. As long as the sink faucet is turned off until needed while teeth brushing, less water is being used. And since taking showers already takes plenty of water (19.5 percent of total daily use), it may be helpful to not extend time in the shower by brushing your teeth.

Does it really save time? Unsure. Some swear they are shaving minutes off their morning routine, and it may be possible if you can multitask while in the shower.

So, what's the verdict? Personally, we may have to disagree with Michael Phelps and others and stick to being a "sink brusher".

Visit DrinkTap's Water Use Statistics page to learn more about typical water use at home.