How does a walk-in bathtub actually work, from door to drain?

A walk-in bathtub works by trading the high wall of a regular tub for a low threshold and a watertight door. You step in, sit down on the built-in seat, close and lock the door, and then fill the tub around you, so the door seal holds the water in for the whole bath. Because the tub fills after you are seated, you use less water than the tub holds when empty, which How much water does a walk-in tub actually use per bath? breaks down model by model.

The Parts That Make a Tub a Walk-In Tub

An Ella walk-in tub is built as one complete unit. The door, the seal, the frame and the threshold are engineered together, and every tub is assembled and tested to order before it ships. These are the pieces doing the work:

• The shell and frame. The acrylic shell sits on a rustproof stainless steel frame. In the first video on this page, the presenter explains why acrylic matters: it is one solid piece of material over the entire bathtub, it is very low maintenance, and if the surface ever gets dull it can be buffed right out. He contrasts that with fiberglass, a multi-layer system built up from a gel coat, whose finish he describes as brittle.
• The door. The door closes on an integrated gasket with a multi-latch gear and shaft mechanism. Depending on the model it swings inward or outward. The Zen, for example, uses an inward-swing acrylic S-shape door, while the Capri and Monaco use an outward-swinging U-shape door with a 3-latch gear and shaft mechanism.
• The low threshold. Instead of climbing over a tub wall, you step over a low sill. The Capri, for example, has a 3.5-inch threshold, far lower than the wall of a standard tub.
• The built-in seat. The seat sits at a comfortable height, so the bather sits upright rather than lowering down to the floor of the tub.
• Grab bars. They give you something solid to hold as you step in, sit and stand.
• The fast-fill faucet and gravity dual drain. These are designed to work together, so the tub fills and empties around a seated bather.

This is also why a door cannot simply be added to an ordinary tub. None of these parts can be fitted to a standard bathtub after the fact, as Can Ella Cut a Walk-Through Opening or Add a Door to My Existing Bathtub? explains.

A Bath from Start to Finish

The order of a walk-in tub bath is different from a regular bath, because you get in first and the water comes second.

1. Step over the low threshold, using the grab bar, and sit down on the seat.
2. Close the door and lock it. The door now presses against its gasket and seals the opening.
3. Turn on the fast-fill faucet and fill the tub with comfortably hot water. Your home water heater does the heating.
4. Once the water is 2 inches above the highest jets, switch on the hydro massage if your tub has it. Air massage, a heated seat and chromatherapy are other options a tub can be built with.
5. Soak for as long as you like, keeping the bath water at or below 100.4 degrees Fahrenheit.
6. Open the drain when you are finished. The water leaves by gravity, and once the tub is empty you open the door and step out.

One Ella model follows the same sequence with a helper. The HomeCare is built for a wheelchair user who bathes with a caregiver: the bather rolls up to the tub, transfers in with the caregiver's help, the caregiver moves the chair away and closes and locks the door, and then the tub is filled. Is Ella's Home Care Related to Ella's Bubbles Walk-In Tubs? describes that tub and who it is for.

How the Water Side Works

Every Ella spec sheet prints water capacity as two numbers. Unoccupied capacity is what the tub holds with nobody in it. Occupied capacity, written as a range, is what you actually use once you are seated and your body is displacing water. Most standard-size Ella walk-in tubs hold 65 to 107 gallons unoccupied and use 30 to 75 gallons per bath. The Standard, for example, holds 65 gallons unoccupied and uses 30 to 50 gallons occupied, while the two-seat Escape holds 145 gallons and uses 85 to 135 gallons. A smaller bather typically uses the upper end of a range and a larger bather the lower end.

Two practical points follow from that. First, your home water heater has to supply the hot fill, so start with a large enough water heater for the tub you choose. The largest single-seat tub, the ShaK, may need a dedicated additional heater. Second, fill time is the capacity divided by the real-world flow at your faucet, so the occupied figure is the better guide when you estimate a fill.

The faucet is chosen at order time. In the second video on this page, the presenter explains that when the order is placed, the tub is pulled and drilled for whichever faucet you select, and he names the two-piece high-flow faucet, the five-piece high-flow faucet and the TCV faucet. A tub equipped with an Ella thermostatic faucet package includes a built-in Thermostatic Control Valve that mixes hot and cold to a set temperature. On the way out, the water leaves through drains on the opposite side from the door: a right-side door tub has its drains on the left, and a left-side door tub has its drains on the right, as you face the tub.

How the Massage Systems Work

The therapies are separate systems under the tub, and each one works in its own way.

• Hydro massage. A pump pulls bath water through an in-line heater and pushes it back out through the jets. The heater maintains your bath temperature but does not raise it, and it switches on and off with the pump, so there is no heater button or thermostat to set. What Is an In-Line Water Heater on a Walk-In Tub? covers this in detail.
• Independent foot massage. On tubs with this feature, the heater is attached to the foot massage pump, so running the foot jets is what keeps the water warm.
• Air massage. An air pump sends air through its own set of jets. It has no heater. On Ella three-speed push controls, the first press is high speed, the second is medium, the third is low, and a fourth press turns the system off.
• Auto Purge. About 20 minutes after the air pump is turned off, the air system switches itself on for 120 seconds to blow residual water out of the air lines. It is fully automatic, cannot be stopped, and is completely normal.

Air-only and soaking tubs have no hydro pump and no heater, so they work simply as a deep, seated soak. To keep a jetted system fresh, the routine is a vinegar flush before first use and once a month: combine 2 cups of white vinegar with 2 cups of water, fill the tub to one inch above the highest jets, add the mixture, run the tub for 10 minutes, then drain.

How It Fits Your Bathroom and Who Works on It

Most Ella walk-in tubs go into the same three-wall alcove your current tub occupies, so you keep the room's layout and plumbing locations. When the tub is shorter than the alcove, an extension panel fills the gap, and a knee wall can hide the plumbing or carry fixtures. Ella tubs use their own deck-mount faucet packages, so your existing tub spout and handles are normally replaced rather than reused.

Installation is done by a licensed, experienced local contractor, with free technical support from Ella available to guide the work. The Lifetime Limited Warranty covers parts, including supporting equipment such as the in-line heater. When a part is needed, it ships under the warranty and a local licensed plumber or electrician does the labor. For help with a specific tub, reach out at ellasbubbles.com/support or call (800) 480-6850.

Watch: Luxury Faucet Options for Your Walk-In Tub, Voted Best/Safest 2020 | Ella’s Bubbles with chapters and a full transcript.

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• Do walk-in tub doors leak, and how is that prevented?
• How fast will my walk-in tub fill? Fast-fill faucet expectations and operation
• How Fast Does a Walk-In Tub Drain? Dual Drain Technology Explained

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