Unfortunately, unless you're taking 20-minute showers—more on that later—baths just can't measure up in terms of water usage. According to the U.S. Environmental Protection Agency (EPA), a full bathtub requires about 70 gallons of water, while taking a five-minute shower uses 10 to 25 gallons.
With a low-flow showerhead, you can expect to use about two gallons of water each minute, equating to 10 gallons over a 5-minute period. If a standard showerhead is fit, the shower will likely emit around an extra half gallon of water per minute, so a 5-minute shower will use in the region of 12.5 gallons.
The average American shower uses approximately 15.8 gallons (59.8 liters) and lasts for 7.8 minutes at an average flow rate of 2.1 gallons per minute (7.9 lpm).
The average bath uses about 80 litres of water. Over the course of four minutes a normal shower head produces about 36 litres. Less hot water also means fewer carbon emissions.
If you have a low-flow showerhead installed, you can expect to use about two gallons of water per minute, equalling 20 gallons throughout a 10-minute shower. With a standard showerhead, around half a gallon more water will emerge each minute, so a 10-minute shower would use somewhere close to 25 gallons.
According to the U.S. Environmental Protection Agency (EPA), a full bathtub requires about 70 gallons of water, while taking a five-minute shower uses 10 to 25 gallons. You might argue that very few people fill the tub to the top, but a simple calculation shows that either way, baths use more water.
Flush Facts
Design improvements have allowed toilets to use 1.28 gallons per flush or less while still providing equal or superior performance. This is 20 percent less water than the current federal standard of 1.6 gallons per flush.
The shower
A water-efficient showerhead uses approximately 9 litres per minute. An older style showerhead uses approximately 19 litres per minute - that's 10 litres more! Having a daily 5 minute shower with an older style showerhead uses about 36,500 litres of water a year.
Estimates vary. The folks at Water Footprint Calculator say the average at-home water use is 60 gallons per person daily. However, the US Geological Survey puts the average at 80-100 gallons per person. The wide range depends significantly on the habits of the individuals in your home.
The total running time of this kind of shower can last less than two minutes – using an initial thirty seconds or so to get wet, followed by shutting off the water, using soap and shampoo and lathering, then rinsing for a minute or less.
On average, approximately 70 percent of that water is used indoors, with the bathroom being the largest consumer (a toilet alone can use 27 percent!).
An ordinary electrically heated shower puts out four litres per minute. So a 19-minute shower is just more than a bath. If you have a power shower, flow rates could be doubled and you'd need just 10 minutes.
Toilets made from the early 1980s to 1992 typically used 3.5 gallons per flush (13.2 liters) or more. Toilets made prior to 1980 typically used 5.0 to 7.0 or high gallons per flush (18.9 lpf to 26.5 lpf). The oldest toilets can use more than 8 gallons per flush (30 lpf).
A bath may be the best option to promote relaxation, reduce fatigue, and alleviate chronic pain. A shower can be a better option if your only concern is being clean every day; plus, if you use the cold water setting for the last few minutes of your shower, it may also help your immune system.
A toilet will normally use about 2-3 gallons per minute (gpm), a shower from 1.5 to 3.0 gpm, a bathroom or kitchen faucet from 2-3 gpm, a dishwasher from 2-4 gpm, and a washing machine from 3-5 gpm. When you start running more than one fixture (sink/dishwasher/toilet/etc.)
Many HE washers are ENERGY STAR certified, which means they use about 25% less energy and 33% less water than regular washers1. ENERGY STAR states that, on average, an ENERGY STAR certified washer uses 14 gallons of water per load, while a standard washing machine uses 20 gallons of water per load1.
How much water is used for the toilet flush depends on various factors. A standard cistern uses around 6 to 9 litres of water per flush, depending on the flush valve settings.
The average system uses approximately 15-16 gallons per minute, per station. Here is an easy formula to help you calculate the approximate amount of water you are using each month.
A typical bucket holds about 20 liters of water. An average shower bath lasts eight minutes or more and can consume 80 liters of water. Hence, a bucket bath saves 75% of water consumption right of the bat.
The largest use of household water is to flush the toilet, followed by taking showers and baths. Toilets account for nearly 30 percent of an average home's indoor water consumption. Older, inefficient toilets can use as much as three to six gallons per flush.
An older toilet uses 7 gallons per flush, a newer one could be as low as 1.6 gallons per flush.
Washing your hands or face with the water running uses about 4 gallons. Turning the water off saves 3 gallons, using only 1 gallon each time you wash up. Washing dishes with the water running uses about 15 gallons in 5 minutes.