In this article, I’m going to show you which uses less water; a bathtub or a shower. We’ll also look at which uses less energy. Since health is an important part of sustainability we’re also going to look at which is healthier to figure out which is the best option overall. For many of us one of the biggest sources of our personal water usage comes when we take a shower or a bath, so it’s important to know which uses less water in order to reduce water consumption. Since energy consumption changes based on how much water you use, it’s also important to know which uses less water in order to save energy.
A bath uses a fixed amount of water each time you use it. In other words, the amount of water you use in a bath doesn’t change the longer you’re in there. On the other hand, a shower does use more water the longer you’re in there. This means shorter showers will use less water than a bath, but as your shower gets longer there will come a point in time where using a bath will use less water. This exact amount of time changes based on how much water you need to fill your bathtub and how much water your shower uses over time.
Let’s start by looking at water usage by a bathtub. A standard bathtub can hold about 42 gallons of water, but you don’t want to fill it to the top because water will spill out when you get in. A good number to use is about 30 gallons of water for each time you use a bath. To figure out how much water a shower uses each time, we first need to know how much water it uses over a minute. If you would like to measure the flow rate of your own shower check out my article on flow rate. The average shower will use about 2 gallons of water per minute. This means if you take showers that are less than 15 minutes you’ll use less water than if you use the bath, but if your showers usually last longer than 15 minutes it would save water to use the bathtub instead. This time may differ a bit depending on how much water you need to fill your bath and how much water your shower head uses per minute, however shower heads don’t usually go above two and a half gallons per minute. This means even in the most inefficient use of water in the shower, you’ll still have about 12 minutes in the shower. After 12 minutes it would use less water to use the bathtub. According to the united states environmental protection agency the average shower is about 8 minutes, so even if you have an inefficient shower head, you would use about 20 gallons of water. 20 gallons of water really isn’t enough to take a bath with unless you can block off part of the tub, so again the answer will change depending on your situation, but on average a shower will use less water.
Since the amount of energy used to heat water depends on the amount of water used a shower will again be the better option in terms of energy. In terms of health and hygiene, many people believe showering would be the best option because in a bathtub you’re sitting in everything that you just washed off yourself, whereas in a shower it just washes down the drain. Now I don’t like to refer to research studies that I haven’t read myself but given the very limited amount of studies being discussed on the topic I don’t have much to go on. The only exception was a 2009 study which showed how bathtubs are one of the highest sources of bacteria in the home and may in fact have more than 100 times the bacteria of a garbage can. I know that my own bathtub will get moldy from using the shower, so altogether it does seem that showering is more hygienic. There are also many dermatologists quoted in articles who seem to support the idea that showering is better because you’re exposed to less water which is better for your skin, but here too I couldn’t find much research, so I can only go on the dermatologist word.
There is a bunch of research that shows the health benefits of bathing in terms of stress reduction, cardiovascular disease, and strokes. Much of this research comes out of Japan where most people take several baths a week. Interestingly, they will usually rinse off in a shower with soap and water before getting into the bath, so that it’s clean. You could try showering on most days to save water and then clean the tub if you want to take the occasional bath.
If you’re looking for a recommendation for a safe cleaning product for your bathtub that you could also use anywhere in your home check out my article on Force of Nature cleaner.
Overall I’d say on average, showers are the more sustainable option, especially because you can take faster showers and reduce your water and energy consumption. In terms of hygiene and skin care, it seems showers are also better, however bathtubs have been shown to reduce other health issues such as stress, so you may want to use showers most of the time to save water and use a bath on occasion.
The best option for you will change depending on your situation so I’d recommend using this article to help you figure that out.