The depth of a bathtub can vary depending on the type and purpose of the tub. Standard bathtub depths typically allow for approximately 12 inches of water, which is enough for most people to comfortably bathe. However, for those who prefer a more immersive bathing experience, soaking tubs should offer at least 14 inches or more of depth so that the water covers the majority of the bather’s body. To determine the water depth of a bathtub, it’s important to measure the distance from the bottom of the tub to the overflow drain.