Bathroom Plumbing Fixtures Are Designed To Save Water, BUT . . .Bathroom plumbing fixtures can save water, but some are water hogs.

. . . some bathroom plumbing fixtures may require a larger water heater, or an auxiliary on-demand water heater. This can seriously affect your investment in a bathroom remodeling project, adding as much as $4,000 to your investment. And it can affect your utility bills. The bathroom plumbing fixture that’s a major influencer of hot water needs is a large tub, whether it’s a hydrotherapy whirlpool, an air bath, or simply a soaking tub. A generous two-person tub that’s 48″ x 72″ x 24″ requires 100 gallons or more, depending on how full you want it to be.

According to Remodeling, a storage water heater must be two-thirds the size of your tub. According to the US Consumer Product Safety Commission, the water temperature of a tub is best between 100°F and 102°F, but some users prefer the water temperature around 104°F, as stated by Jacuzzi. If your standard 50-gallon storage water heater is set to provide hot water at the recommended 120°F, a large tub like the one above will run your water heater dry. It will take at least 60 gallons of hot water mixed with 68°F regular tap water to achieve 100 gallons of 102°F water for bathing. And that’s assuming that your tub won’t absorb and dissipate any of the heat!

For these reasons, I try to persuade my clients to purchase a smaller tub that’s comfortable for one person. 66″ – 72″ x 32″ – 36″ x 21″ is sufficient to get great hydrotherapy results for sore joints and muscles. They can fill the tub to maximum using a standard 50-gallon storage water heater. There’s no need to purchase and install a new water heater or an auxiliary on-demand water heater, unless other appliances and plumbing fixtures are using hot water at the same time (i.e., a dishwasher or washing machine). One thing to keep in mind is that a new whirlpool tub will require a dedicated 15-amp circuit. If your existing panel doesn’t have room for a new circuit, you could be facing a big, expensive surprise!


Plumbing codes started changing in 1992, requiring more water-efficient appliances and plumbing fixtures. The Alliance for Water Efficiency has online information and guidelines. New bathroom faucets are required to provide water flow at a maximum of 2.2 gallons per minute (gpm). Shower heads must provide a maximum water flow of 2.5 gallons per minute. The impact on water usage in general and hot water usage specifically occurs when a bather is using a shower head and multiple body sprays at the same time. A short shower, according to the EPA, is 8 minutes. The bather consumes 18 gallons of water in this time using just a shower head! The water consumption increases to 70.4 gallons in 8 minutes, using a shower head and three body sprays! Until manufacturers started producing water-saving rainhead shower heads, Homeowners had to be careful about their selection, because the shower heads could provide a water flow exceeding 10 gallons per minute! Increasing the water pressure to 80 or 90 pounds per square inch (psi) has made it possible for Homeowners to have a guilt-free rainhead showering experience.

Creating a new bathroom, or doing a full-blown bathroom remodeling is NOT a good project for D-I-Yers. There are too many important factors to consider to take a chance on making an expensive mistake. A professionally trained, experienced bathroom designer will be able to help you make the best decisions, and prepare detailed plans for estimates and construction.

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