Amazing Technology and Ingenuity” Hidden in “Quick-Stop Showers” in Public Baths

The sauna boom has taken root in Japan, with coined terms such as “totonou” and “sakkatsu” being coined. In onsen facilities, it is good manners to wash one’s body before entering the sauna or bathtub. After entering the bathroom, one sits down in front of the bathtub. Many people may have wondered about something here.

The hot water in the shower stops every time, and it is a hassle. ……

Many people may have experienced the same thing not only in hot spring facilities but also in the bathrooms of Japanese-style inns in the countryside. That annoying feeling of having to press a button several times when the hot water stops in the middle of rinsing off bubbles ……. Some people are dexterous enough to hold the lever with their foot so that the water does not stop.

Most of these faucets that shut off the hot water for a certain period of time are currently manufactured by TOTO. It looks like a silver cylinder with a knob on the left side to adjust the temperature, a push button in the center to release the hot water, and a lever on the right side to release the shower.

According to TOTO, the official name of the “quick stop shower” is the “auto-stop shower faucet,” and most of the sales channels are for commercial use. Many customers leave the water running in public bathhouses, and many stores are installing these faucets to save water.

Sonoko Abe of TOTO’s Public Relations Department explains the mechanism.

First, when the button is pressed, the water valve inside the faucet is pushed open, allowing water to flow out. When the button is released, the water valve, once pushed out, gradually returns to its original position due to the force of water pressure. When the valve returns to its original position, it will naturally close and the water will stop.

In other words, water continues to flow until the water valve, which is moved by the button, returns to its original position due to the water pressure inside the faucet. Even if the button is pressed twice, it does not double the water dispensing time. The water flows for a set amount of time after the last time the button is pressed.

The AutoStop Shower Faucet allows you to change the water flow rate for both the shower and the faucet; according to TOTO, the faucet can be adjusted to deliver up to 7 liters of water and the shower can be adjusted to deliver up to 45 seconds. The faucet is factory-designed to dispense approximately 3 liters of hot water, which is equivalent to a tub of water, and the shower is designed to dispense hot water for approximately 25 seconds, which is the approximate time required for foam to flow down the entire body.

In an actual facility, however, the time required to dispense water is likely to be a little shorter.

Motonobu Matsumoto, owner of Matsumoto-yu, a long-established bathhouse in Nakano Ward, Tokyo, says, “We set the time for the hot water to flow in the shower section to about 12 to 3 seconds.

I have visited many public bathhouses and counted the number of seconds and found that it is usually around that range. 12 to 3 seconds is just right, as I don’t have to press the button as many times, and I feel that I am contributing to water conservation. The size of the water supply tank and the number of people it can accommodate vary from facility to facility, so I think the number of seconds is set to ensure a stable supply,” says Matsumoto.

The size of the water supply tank differs from bathhouse to bathhouse, and if a large amount of water is used at once, there may be a temporary shortage. In this sense, the “quick stop shower,” which contributes to water conservation, plays an important role.

In addition, Matsumotoyu completely renovated the faucets in the building last summer, replacing them with auto stop shower faucets. Until then, the bathhouses had manual faucets with separate hot and cold water taps, such as those seen in the hand-washing areas, and water continues to flow when turned on, but for one reason or another, they switched to TOTO faucets.

Until then, we had installed a manual type of faucet that had a separate hot and cold water supply for the hand washroom, but we switched to a TOTO faucet for a certain reason. Until then, we used to use a faucet made by a manufacturer called ‘Takara,’ but they don’t seem to be manufacturing it anymore. Even if the faucet were sold by another manufacturer, if the model is an older type, in many cases the parts themselves, such as gaskets, are not sold when they break down. Considering continued operation, I think it is safe to use TOTO products,” says Matsumoto.

In recent years, an increasing number of sento (public bathhouses) have undergone renovations in line with the boom in the market. In addition to saving water, the replacement with “showers that stop immediately,” which help prevent temporary depletion of water, is likely to accelerate.