Short answer
A walk-in tub is a deep bathtub with a watertight door, a low step-in threshold and a built-in seat. You step in, sit down, close the door, then fill the tub. You stay seated while it fills and drains. Fill times run about 6 to 15 minutes and drains about 5 to 10, per HomeGuide.
Key facts
- Walk-in tubs take 6 to 15 minutes to fill and 5 to 10 minutes to drain on average, or about 2 minutes with a speed drain feature, per HomeGuide (2025).[1]
- Standard walk-in tubs hold people up to about 300 pounds; bariatric models raise that to about 600 pounds, per This Old House (2026).[2]
- Kohler lists a 3-inch step-in threshold and a 17-inch seat height on its walk-in bath, and says it is designed for a standard 50-gallon water heater.[4]
- HomeGuide (2025) puts a walk-in tub at $4,000 to $18,000 with installation.[1]
What a walk-in tub is
A walk-in tub (also sold as a walk-in bathtub, step-in tub or senior bathtub) is a bathing fixture with a low step-in threshold, a door, a built-in seat and, often, jets or other comfort features[1]. Compared with a standard bathtub, it has a lower threshold and higher walls[2]. Instead of climbing over a tub wall, you open the door, step over a low sill and sit down.
How a walk-in tub works
The door and the step-in
The door seals against a gasket when you close the latch. Thresholds vary by model. Kohler lists a 3-inch step-in on its walk-in bath[4], and This Old House says other tubs can reach about 7 inches[2]. If stepping is hard, compare threshold heights before you compare anything else.
Doors open one of two ways[3]:
- Inward-opening: the most common and usually the least expensive, but you need room inside the tub to move around the door.
- Outward-opening: easier to get in and out, and This Old House says they can add $500 to $2,000 because of more complex sealing.
Wide-entry, ultra-low-threshold doors for wheelchair users can add $1,000 to $3,000[3]. HomeGuide notes that swing-out doors may leak if they are not latched properly[1].
Filling and draining
You sit inside with the door closed while the tub fills, and you stay seated until it drains. That is the main trade-off. HomeGuide puts typical fill times at 6 to 15 minutes, or about 3 minutes with a quick-fill faucet. Draining takes 5 to 10 minutes on average, or about 2 minutes with a speed drain[1]. This Old House describes quick drains as 4 minutes or less, against 6 to 15 minutes for a conventional drain[2]. One American Standard model uses a pump that empties the tub in less than 2 minutes, per the maker[6].
Kohler says fill and drain times depend on your home's pipe size and water flow rate[5]. Ask the installer to estimate times for your house, not the showroom.
Seat height
Kohler lists a 17-inch seat height on its walk-in bath[4]. As a reference point, the 2010 ADA Standards set bathtub seats at 17 to 19 inches above the bathroom floor (section 610.2)[7]. Those standards are written for public buildings, but the numbers are a useful yardstick when you compare models.
Types of walk-in tubs
| Type | What it does | Tub-only price range |
|---|---|---|
| Soaking | Deep seated soak, no jets | $3,000 to $6,000[1] |
| Air jets (aerotherapy) | Air bubbles for a gentle massage | $5,000 to $11,000[1] |
| Hydro jets (whirlpool) | Water jets for a stronger massage | $5,000 to $12,000[1] |
| Air and hydro jets | Both systems | $6,000 to $13,000[1] |
| Tub and shower combo | Bathe seated or shower | $2,500 to $10,000[1] |
| Bariatric | Wider seat, higher weight capacity | $5,000 to $13,000[1] |
| Wheelchair-accessible | Wide outward door for transfers | $5,000 to $12,000[3] |
| Two-person | Two seats | $7,700 to $20,000[1] |
Prices are for the tub only, before installation, as of 2025 and 2026. This Old House says standard walk-in tubs accommodate people up to 300 pounds, while bariatric tubs raise that to 600 pounds[2]. Jetted tubs add an electric pump, which affects the installation (see below).
Size and water heater capacity
Most walk-in tubs are built to fit a standard tub alcove. Kohler gives the average walk-in tub as about 60 inches long by 32 inches wide and 38 inches high, with small models around 36 by 32 inches and large ones up to 60 by 40 inches[4]. Its own bath can be sized from 52 to 60 inches long and 28 to 32 inches wide[4].
Walk-in tubs are deep, so they hold a lot of water. One American Standard 32 by 60-inch whirlpool model lists an 80-gallon capacity[6]. That matters for your water heater:
- Kohler says its bath is designed for a standard 50-gallon water heater, though the heater's age and condition affect performance[4]. Its FAQ adds that a 40, 50 or 75-gallon heater can be enough depending on where you live[5].
- HomeGuide notes that high-capacity tubs may need a newer, larger or tankless water heater, and that replacing one costs $1,400 to $5,600 installed[1].
Ask whoever quotes the tub to check your water heater's size and age in writing.
Walk-in tub vs walk-in shower
| Walk-in tub | Walk-in shower | |
|---|---|---|
| How you bathe | Seated soak; some models add a shower | Standing, or seated on a bench or fold-down seat |
| Waiting | Sit inside while it fills and drains[1] | No fill or drain wait |
| Hot water | Large volume; may need a bigger heater[1] | Normal shower use |
| Entry | Low threshold plus a door you must latch | Can be built with a low curb or no curb |
| Typical installed cost | $4,000 to $18,000[1] | Tub to shower conversion: $3,500 to $15,000, or $1,000 to $8,000 with a prefab kit[1] |
HomeGuide lists the downsides of walk-in tubs as higher cost, the wait while filling and draining, higher water and heating use, and the risk of a leak if a swing-out door is not latched[1]. A walk-in shower avoids the wait and the hot water load, but it does not give you a seated soak. For a closer look at shower options, see accessible and curbless showers and the walk-in showers section.
What installation involves
HomeGuide says installing a walk-in tub takes 1 to 2 days, and a simple swap can be done in a single day[1]. Common pieces of the job:
- Removal of the old tub and any surround repair.
- Plumbing: new drain and supply connections. HomeGuide notes some homes need larger pipes to cut fill and drain times[1].
- Electrical: jetted tubs and heated seats need power. This Old House says any installation that combines water and line voltage needs a licensed electrician and GFCI protection[3].
- Pump access: for whirlpool tubs, the 2021 International Residential Code (section P2720.1) requires access to the circulation pump, with an opening of at least 12 by 12 inches where the maker does not specify a size[8].
- Scald protection: the same code (section P2713.3) requires bathtub and whirlpool valves to have a temperature-limiting device set no higher than 120°F[8].
- Extension panels to close gaps when the tub is shorter than the old one, at about $250 to $300[1].
Local codes vary, and plumbing or electrical work usually needs a permit. The walk-in tub cost page covers pricing in detail, and the brands compared guide explains how to read warranties and spec sheets.
When to call a pro
- Any jetted or heated tub: the wiring and GFCI protection should be done by a licensed electrician.
- If the tub needs a new drain, larger supply lines or a bigger water heater: that is work for a licensed plumber, usually with a permit.
- If the floor near the old tub is soft or stained, which can mean water damage under the tub.
- To get a firm price: national ranges cannot price your bathroom or your plumbing.
More questions
Can a walk-in tub also be a shower?
Yes. Many models come as a tub and shower combo with a handheld or fixed shower head. HomeGuide (2025) lists walk-in tub and shower combos at $2,500 to $10,000 for the tub alone. Kohler says its shower package cannot be added to a walk-in bath that is already installed, so decide before you order.
Do walk-in tubs leak?
They are built with watertight door seals, but HomeGuide (2025) says leaks can come from worn door gaskets, installation errors or plumbing connections. It also notes that swing-out doors can leak if they are not latched properly.
Will a walk-in tub fit where my old tub is?
Often, yes. Kohler says its walk-in bath can be sized from 52 to 60 inches long and 28 to 32 inches wide to fit a standard tub space. HomeGuide notes that a shorter tub may need extension panels, at about $250 to $300, to close the gap at the ends.
Sources
- How much does a walk-in tub cost? (2026), written Aug 27, 2025, HomeGuide. Accessed 2026-10-15.
- Best walk-in tubs of 2026: cost, types, and features (updated Jun 11, 2026), This Old House. Accessed 2026-10-15.
- How much does a walk-in tub cost in 2026? (updated Jun 12, 2026), This Old House. Accessed 2026-10-15.
- KOHLER Walk-In Bath dimensions, Kohler Co.. Accessed 2026-10-15.
- KOHLER Walk-In Bath FAQs, Kohler Co.. Accessed 2026-10-15.
- Acrylic Luxury Series 32 x 60-inch walk-in tub with whirlpool system (product page), American Standard. Accessed 2026-10-15.
- 2010 ADA Standards for Accessible Design, U.S. Department of Justice, ADA.gov. Accessed 2026-10-15.
- International Residential Code 2021, Chapter 27 Plumbing Fixtures (as adopted without amendment by Colorado DFPC), UpCodes. Accessed 2026-10-15.
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