Shower vs Bath Water Usage: The bathroom constitutes the bigger half of all domestic house water usage. With so much water being used, there are easy opportunities to save both water and money.
Shower vs Bath Water Usage: The debate
The most important bathroom activity is bathing. There is a big debate whether bathing in a bath uses more water than taking a shower.
How much Water does a Shower use
The biggest factors here are flow rate and length (total time) of a shower.
An ordinary electrically heated shower puts out four litres (1 gallon) per minute. But the next statistic will suggest it is more like double that.
Home Water Works says that in most homes, showers are the third-largest user of water after toilets and clothes washers. The average American shower water usage is 17.2 gallons with the average shower length being 8.2 minutes. The average flow rate is 2.1 gallons per minute.
What is the average shower time
Men shower at an average of 7 minutes while women shower at an average shower length of 9 minutes.
An older person of say age bracket of 50 years and above showers for 4 to 5 minutes while teenagers can shower up to 25 minutes.
With such diverse variation, it would be best to rather use the average statistic quoted by Home Water Works : 8.2 minutes.
How much Water does a Bath use
The biggest factor here is the size of a bath.
A bath uses between 50 to 150 litres (14 to 40 gallons) of water per fill, depending on the water level.
A bath filled about a third of the way up (which takes the water level over your belly button when you lie down) requires around 75 litres (20 gallons).
What uses more water, a Bath, or a Shower
Lets take the lowest then the average and finally the highest of all stats on both a bath and a shower and make a broad comparison.
Lowest Shower vs Bath Water Usage
Bath = 50 litres (14 gallons)
Shower = 4 liter (1 gallon) per minute (low flow rate shower head and setting) for 4 minutes (old person) = 16 liter (4.2 gallons)
So in this case the shower uses significant less water than a bath, at just about one third. (16 vs 50 | 4.2 vs 14)
Average Shower vs Bath Water Usage
Bath = 75 litres (20 gallons)
Shower = 5.9 liter (1.55 gallon) per minute (average between highest and lowest) for 8.2 minutes (average American) = 48 liter (12.7 gallons)
In this instance the shower uses less than the bath, at approximately 2 thirds. (48 vs 75 | 12.7 vs 20)
Highest Shower vs Bath Water Usage
Bath = 150 litres (40 gallons)
Shower = 8 liter (2.1 gallon) per minute (high flow rate shower head and setting) for 25 minutes (teenager ) = 199 liter (52.5 gallons)
In this instance the shower uses less than the bath, at approximately 3 quarters. (150 vs 199 | 40 vs 52.5)
A very conclusive answer on the debate
In all 3 cases (lowest, average and highest) clearly the shower uses less water than the bath.
Still your unique home situation may be different. You might have a very small bath or a huge luxury bath (like the royalty of the Roman empire). This will factor the calculations and results quite differently.
As already mentioned with a shower the two main factors is flow rate and total shower time. So you might have a very high flow shower head (ex. Original HIGH FLOW SHOWER HEAD – 10.5 GPM – Water Blaster Brand) and very high pressure in your water supply. I have even seen people completely removing the shower head and run the shower without it, and even turn the taps fully open. So cases like this might also tip the scales.