The average bathtub is designed to fit one average-size person comfortably with enough room to recline. Bathtub capacity is calculated as if no The average elongated bathtub in North America holds 58 gallons of of the overflow drain; the capacity of a 30-inch tub with a depth of 14 Bathtubs are available in many sizes, a typical size being 30 inches wide and 60 inches long. The inside measurements of this tub could be 23 inches wide, 15 inches deep to the water level and 54 inches long. This tub holds about 80 gallons of water. If this is an extra deep tub, it might hold up to 110 gallons. A very small bathtub might hold 40 gallons, while a larger single person bathtub could easily hold 100 gallons or more. My bath tub holds 110 gallons (pictured above), and my 50 gallon water heater couldn’t even fill it with enough hot water to use the whirlpool jets. That’s how my house was built, back in 1998. As the average UK bathroom is around 2.3m x 2.7m in size, this would make sense, as it still leaves at least 0.7 metres or 1 metre of clear space, depending on The average bathtub volume has also increased as a result. Generally, many Their maximum capacity exceeds that of a standard bathtub. What is the capacity of an average, US, standard run-of-the-mill built in bathtub filled up to the very bottom of the overflow? Thanks! Let me Most bathtubs hold between 30 and 50 gallons of water. The average bath tub soaker uses the tub at half capacity in order to allow for water displacement when the person is in the tub. Bath water facts as discovered and used by Harwood and Associates, plumbers Note; an average 1700 x 700mm bath holds approximately 180 litres up to Even though whirlpool bathtubs might visually appear to be larger than normal, in many cases these tubs come in standard alcove-ready sizes.