Bathtub: correctly estimate the amount of water for bathing
Do you have any idea how much water is in the bathtub? With a little care, you can assess these better and even save water. Because most of the time you waste useless water in the bathtub.
Ways to estimate the amount of water in bathtubs
You have the following options to estimate the amount of water in bathtubs:
- The manufacturer's information on the volume of the bathtub gives an approximate idea of the amount of water in bathtubs. But these are often imprecise and are of little use if you don't know what brand your bathtub is. But you can get an overview based on the dimensions and shape of your tub. With older tubs, you can only calculate the amount of water.
- Before you go into the tub, write down the water level on the water meter and do so after bath again. Subtract the old water level from the new one and you will know exactly how much water your full bath has used. Of course, this is only possible if no other consumers are drawing water via this meter at the same time.
- You will probably be amazed that this amount of water differs significantly from the assumed amount. Because in this case you not only record the amount of water in the bathtub, but also the water that you usually also use when using the hand shower.
But this is much more important than the amount of water you used to use the shower head Amount of water that disappears completely useless through the overflow if you fill the bathtub incorrectly to have.
Many apartments and houses in old buildings do not have a shower cabin, but only one ...
Calculate the amount of water from tubs
Older bathtubs are usually built in a cuboid shape or can be viewed as a column with a trapezoidal base if you imagine the tub to be set up vertically on the head or base.
- Inside, measure the width of the tub at the bottom and at the height of the overflow. Add the two distances together and divide the result by two.
- Now you need to measure the height of the tub from the floor to the overflow and multiply that by the previous number. You now have the area of the trapezoids, which are assumed to be the base area for the head and foot sections.
- Now you still need the length of the bathtub. Multiply this by the area you calculated earlier. If you measured in cm you know how many cm3 Your tub will hold when it is filled to the point of overflow. Divide the size by 1000, then you know how many liters the tub holds and again by 1000, then you have the m3. Compare this theoretical water consumption with the real one.
- Stand on the scales and determine your weight. Since humans have roughly the same density as water, you displace as much water in the tub as you weigh. So if you weigh 70 kg, 70 l would disappear uselessly through the overflow if you had previously filled the tub to this point.
70 l are approx. 10 cm difference in water height. If you use significantly more water than the calculation described above, it is because you have filled the tub too high.
Save water in the bathtub
- Remember, when we talk about the usable volume of bathtubs, we mean the amount of water up to the overflow. Fill the tub up to this point before you are in it, then waste a considerable amount of water as described. For example, a person weighing 70 kg uses 220 liters instead of 150 liters of water when bathing.
- So either get into the bathtub first and then fill it, or note the water level in the bathtub when you leave it after the bath. Then only fill the tub up to this limit.
- Estimating the right amount of water in the bathtub can save a lot. The water prices are usually a little under 2 €, plus a little over 2 € wastewater fee. So 70 liters of wasted water cost an average of 28 cents. If you take a bath every day, that's over € 100 a year.
