Water depth is an important attribute when selecting a tub, whether it is a soaking tub, whirlpool or air bath. If you get me on the phone you will hear me state that I never want to have to decide if I am going to soak my shoulders or my knees, I want to be be covered with water. On a cold winter day I would be perfectly happy using a snorkel and being totally submerged!
How much water does a tub hold? It depends on the tub. Every tub has an overflow. This is a 2 1/2″ hole drilled below the tub rim. When the water level reaches the overflow it flows into the drain to keep the tub from overfilling. Where the overflow is drilled depends on the tub, the tub’s technical sheet will guide you. This is a picture from the MTI Andrea 17 Technical Sheet:
15 1/2″ from the bottom of the tub to the center of the overflow. Since water will flow out from the bottom of the overflow hole, this bath will hold just over 14″. I have heard that installers have put the overflow cover on upside down so the slot is at the top. Since the water fills to the top of the overflow hole, water depth would be just under 17″. There is also the option of using a product like Deep Water Bath Overflow Cover. This is a clear plastic cup with suction cups. Place it over the overflow with the hole at the top. Works the same as installing the overflow cover upside down.
What depth is deep enough? It depends on your body and how you recline in your tub. Some sit upright against the backrest. I slouch, probably because of my quest to have water over my shoulders. As I slide down into the tub I will have to bend my legs. That’s fine for me, I am totally comfortable as long as my knees are covered. This picture shows more of the technical information. 
It tells me that the floor length is 39 1/8″. At this point you can compare your current tub’s length to check the fit. Or you can mark the tub length on the floor, sit (slouch) against a wall, and see how you fit. If you have to bend your knees, measure from the floor to your knees to see the water depth required.
Is there such a thing as a tub being too deep? Yes. The technical sheet will also give you gallons of water the bath will hold. In the sample we are using it is 51 gallons. 2/3 or 3/4 of the water will be hot water, the rest is cold. So this tub will take 34 – 38 gallons of hot water. No problem with a 40 gallon water heater. Let’s take a look at one of our deepest tubs – Hydro Systems Monterey. This is a two person, 72 x 42, tub with a center (side) drain and two sloping backrests. The floor length is 50″ and depth to overflow is over 20″ – lot’s of soaking room. Gallons of hot water is 60 – 68. To much for a 40 or 60 gallon water heater.
Unfortunately you need to do a little research to find a deep soaking tub. Start with the needed outside dimensions. Our sister site Tubzlady.com will show all our baths by size. Find a few tubs you like the features of, then explore the technical sheets to find the best fit. We are here to help ~ 866-380-0303
