Hot Water Requirements for Walk-In Tubs

To support our last blog post on “Why a Walk-In Tub is Right for You”, I’d like to respectfully submit another article that supports this claim that came to us from a Walk-In Tub manufacturer with a stellar reputation for excellent customer service and superior products, Bliss Tubs of Covina. The following has been taken from an informational flyer of theirs that I felt is worthy of our blog:


The customer’s hot water heater should be assessed during the walk-in tub planning process. For a regular size Bliss wlk-in tub such as the B3052 and B3054 models, many Bliss purchasers have been happy with the hot water delivery from their existing 40 gallon tanks. However, as discussed below, major hot water heater manufacturers recommend a 50 gallon water heater.

In addition to the current heater’s capacity, the heater’s age and location can affect the amount of hot water that can be delivered to the walk-in tub. As water heater’s age, their performance declines. Location of the hot water heater relative to the location of the walk-in tub can also have an impact.

Tank Heaters

For a regular size Bliss walk-in tub as the B3052 and B3054 models, the recommended minimum tank size for electric or gas tank water heaters is 50 gallons. Normally one can assume a 70% hot water output from any tank heater (tank heater manufacturers can provide specifications and reccomendations.) A 70% output should provide roughly 35 gallons of hot water from a 50 gallon tank with the thermostat set to the industry standard of 120 degrees F.

As a construction industry rule of thumb, the water mixture for a comfortable bath is roughly two-thirds (2/3) hot water to one-third (1/3) cold water. Since the typical water requirement to fill a regular size Bliss walk-in tub is 40-50 gallons depending on the user’s size, roughly 30-35 gallons of hot water will be needed for the fully filled occupied tub.

As a side note, the BTU rating (for gas heaters) and the wattage (for electric heaters) only have an effect on the recovery rate of the hot water level for the heater, not the total possible hot water output.

Tankless Heaters

Tankless water heaters require special consideration with regards to water flow rate and temperature rise from the source. When opting for a tankless water heater both ratings should be as high as possible. Flow rates vary by heater manufacturer and model. Contact the water heater manufacturer for exact specifications and recommendations. On average, the rise needs to be around 70 degrees F. For example, this will take 50 degrees F incoming cold water and raise it to 120 degree F hot water output. These two factors should be chosen based on the homeowner’s budget, current electrical setup and desired fill time. As a point of reference, Bliss Tubs equips its tubs with faucets capable of 18 gallons per minute flow rate.

For more information regarding the use, care and functionality of walk-in tubs visit or come in and see a few Walk-In Tubs yourself in our showroom! Our team members will gladly walk you through the process of installing, using and caring for one of these tubs if you are considering having one of your own.

Bliss Tub

Bliss Tub – B3054

Pykles Remodeling – 8348 Center Dr. Suite A – La Mesa, CA – 91941 – (619) 463-1600 P – (619) 668-4683 F