How much water does a walk-in tub hold?

Average water capacity of walk-in tubs

Walk-in tubs typically hold between 40 and 80 gallons of water, though larger models, such as those designed for two people or bariatric users, can have greater capacities. In addition, whether the tub is occupied or unoccupied can affect water capacity. When occupied, the actual water volume required for a bath will be less than the tub's total capacity, as the bather's body displaces some of the water.

Water capacity variation

For example, here’s how water capacity varies by model from Ella’s Bubbles.

Walk-in tub dimensions and features

Consider the tub's dimensions, specific features and your intended use when evaluating water capacity. Understanding these factors can help you choose a walk-in tub that meets your needs and expectations regarding water usage and bathing experience.

In addition to model type, there are other key factors that can influence a walk-in tub's water capacity, including:

• Dimensions: Generally, the larger the tub, the more water it can hold. For instance, a standard walk-in tub measuring 28 inches wide, 51 inches long and 41 inches high can hold about 61 gallons with a 120-pound person inside. A slightly larger model, about 30 inches wide, 59.5 inches long and 36 inches high, has a higher capacity of 71 gallons.
• Features: Built-in seats and water jets can reduce a tub's overall water capacity by taking up space. If your tub has hydrotherapy jets, it's often best not to overfill it. The jets create water movement, which can cause splashing. In these cases, you might find it best to fill the tub just above the highest water jet rather than to a preferred fill level.

Water heater requirements for walk-in tubs

Before you buy a walk-in tub, it's important to check if the size of your current water heater can handle the extra hot water needed. Walk-in tubs hold significantly more water than standard bathtubs.

For example, a typical bath/shower combination only uses about 34 to 42 gallons of water. Your existing water heater, which may work fine for your current tub, might not be powerful enough to fill a larger walk-in tub with a water capacity of 45 gallons or more.

Also, to ensure you have enough hot water for your walk-in tub and other household needs, consider your household size. If others are simultaneously using hot water for tasks like running the dishwasher or taking a shower, your hot water demand increases.

Recommended tank sizes

The U.S. Department of Energy provides guidelines for water heater storage tank sizes based on the number of people in your household.

What is my water heater’s capacity?

To find out your current water heater's capacity, look for a printed label on the unit itself. This label will state the water capacity in U.S. gallons. If the label is missing, consult your water heater's owner's manual. Many manufacturers offer digital versions of their manuals online, making it easy to find the information you need.

Fill and drain times for walk-in tubs

A standard walk-in tub typically takes five to 10 minutes to fill. However, this can vary quite a bit. Larger tubs with greater water capacity will naturally take longer to fill.

Some walk-in tub models are designed for faster filling. For instance, Safety Bath offers models with high-flow faucets that deliver up to 14 gallons per minute. This feature can fill a standard walk-in tub in four minutes or less, significantly reducing your waiting time.

Why water pressure matters

Water pressure can play a key role in the amount of time it takes to fill a bathtub; low water pressure will result in longer fill times. Several factors determine the water pressure in your home:

• Pipe conditions: Leaking or corroded pipes can restrict water flow and reduce pressure throughout the home.
• Water heater: Sediment buildup inside your water heater can obstruct flow and decrease pressure. It’s recommended to flush the tank at least once a year to maintain performance.
• Water pressure regulator: A faulty or incorrectly set water pressure regulator (usually located near the main shut-off valve) can cause pressure to drop significantly. A trusted plumber can help identify the causes of low water pressure in your home and provide effective solutions.
• Municipal supply limitations: Your local water supply may be delivering water at lower pressure due to city infrastructure, construction or maintenance work.
• Elevation and distance from source: Homes on hills or farther away from the main water line may naturally receive lower water pressure.

Draining times

When you're finished bathing, draining the tub can take anywhere from six to 15 minutes on a standard model. Just like with filling, many manufacturers offer fast-draining models that can empty the tub in four minutes or less.

» RELATED: Questions to ask a walk-in bathtub company

Water usage efficiency tips

Walk-in tubs generally use more water than traditional bathtubs, which could mean a higher water bill each month. However, some models are designed with features to improve water efficiency. Consider these water-saving features to help manage your monthly water consumption and associated bills:

• Low-flow faucets reduce the amount of water used.
• Anti-scald technology regulates hot water to prevent burns and helps maintain a consistent temperature, reducing the need to add more water.
• Ergonomic designs with built-in seating can cut water usage by up to 30%. Certain models even have heated seats, which can help regulate body temperature while bathing.
• Hydrojets with in-line heaters circulate and warm the water, preventing it from getting too cold and eliminating the need to add hot water.

Pros and cons of walk-in tubs

Walk-in tubs offer several advantages, especially for seniors or individuals with disabilities, by providing a safe and accessible bathing solution. But there are also disadvantages to consider.

Benefits of walk-in tubs

• Comfort: These tubs are designed for a luxurious bathing experience, often featuring heated seats, backrests, hydrotherapy and air jets.
• Safety: They include safety features such as grab bars, low thresholds, slip-resistant flooring, anti-scald valves and anchored seating to prevent falls and help you maintain independence.
• Resale value: In most cases, a walk-in tub won't decrease your home's value and may even increase it, especially in areas with a high senior population.

Drawbacks of walk-in tubs

• Cost: Walk-in tub prices generally range from $2,000 to $20,000, which is much more expensive than standard bathtubs.
• Installation: Many walk-in tubs use electricity, requiring a specialized installer familiar with both plumbing and electrical components for a safe setup.
• Structural Considerations: You might need to make home upgrades, such as a new water heater or plumbing system, to accommodate a walk-in tub.

Expert advice

Before buying a walk-in tub, consult with a contractor to assess your home's structural needs. As Cornforth pointed out, "these tubs hold more water, meaning this extra weight can stress old floor joists, especially upstairs." A general contractor can help determine if your floors need reinforcement before installation.

 When choosing an installer, Cornforth also advises finding a contractor with experience in installing walk-in tubs. Unlike standard tubs, walk-in tubs often use electricity for features like water jets and heated seats. Therefore, Cornforth stresses the importance of having someone who can properly install a GFCI circuit to prevent electrical shocks.