How Many Gallons Does a Bathtub Hold?
So, you’re shopping for a new bathtub and you’ve done your measurements-mapped out the space for installation, but something that you haven’t fully understood is the weight when it’s filled. An often overlooked but very important question, as understandably, a bathtub weighs significantly less unfilled than filled. A gallon of water weighs roughly 8 pounds, so if your bathtub can hold around 100 gallons of water, that is roughly around 800 pounds of strain on your floor, not accounting for your body weight as well as the material of your bathtub itself, so yes, it is important to know the capacity of your tub.
In general, there is no ‘standard’ bathtub size as they are quite a large number of varying sizes on the market, but there are typical or more common measurements, which is what will be provided below. On average, a bath uses anywhere between 35-50 gallons(132-189 liters) of water whereas a ten minute shower uses roughly only 25 gallons(94 liters). So, outside of just general heating costs, baths should be regulated to a more special treat, rather than a daily routine as it can be quite expensive on your water and utilities bill.
Common, Smaller and Larger Bathtubs
To start, the standard bathtub will hold roughly around 80 gallons (302 liters) of water. Much smaller bathtubs can only hold around 40 gallons (150 liters) of water, which typically are more suited for smaller children or function more as a shower space. Whereas much larger bathtubs can easily hold upwards of 100-110 gallons (378-410 liters) of water and these encompass your single person baths that can easily accommodate the additional water weight.
Freestanding, Corner and Other Bathtubs
In addition to looking quite different aesthetically, each bathtub will vary their overall water capacity depending on the style and type of bathtub as well. As a rule, freestanding bathtubs are quite large, allowing for more water capacity, corner bathtubs are small, so less water, and drop-ins sit somewhere in between freestanding and corner bathtubs.
Since they are designed for single person bathing, most freestanding bathtubs can hold anywhere from 90-100 gallons of water. (340-378 liters). Corner bathtubs are a bit smaller, designed for more confined spaces, which means water capacity will be significantly smaller, usually able to hold roughly anywhere from 40-60 gallons(150-227 liters) but usually the 40 gallon limit is more common. Acrylic drop-ins fit the more standard bathtub capacity model, usually holding anywhere from 60-80 gallons, though larger sizes do exist as they have quite a large range of models and styles to choose from. on average(227-302 liters). Which brings us to shower/tub combos, which have a similar spectrum with freestanding and acrylic drop-ins, as most of these showers are made with either of these styles as the base. On average, you are looking at a minimum of 60 gallons, with a higher end of 110 gallons. (227 liters and 416 liters respectively.)
Another thing to discuss is that with the additional water capacity of your bathtub, you need to also consider the capacity of your water heater. The average home usually houses a water heater with a capacity of around 30-36 gallons of water. If your home supports around 4 or more people, you generally have a larger water heater with a capacity of around 40-60 gallons of water. This is important, as the more water your bath and showers can hold, the more powerful and larger your water heater needs to be in order to support your long relaxing showers/baths to have a consistent flow of heated water.