Why Shower Routines Make People Spend Longer in the Shower

One person may spend twice as long in the shower as another, but the difference is unlikely to be explained by age, gender or household size.

A new study suggests that the explanation is found in the shower routine itself.

Researchers installed small sensors in the showers of 319 German households for one winter. Across 40 days, the devices recorded 8,550 individual showers.

Factors linked to longer showers

The sensors tracked the length of time the water was running, the number of times it was stopped, and conditions within the room.

Participants were not able to time their own showers because the display that could have revealed the count was concealed.

For 958 showers, the researchers linked the sensor data with questionnaires completed by participants afterwards, covering their age, household circumstances and the products they used.

Researchers at the University of Surrey created a comprehensive model to identify what predicted a longer shower. It assessed 14 factors simultaneously, allowing each factor to be considered while the others remained constant.

When repeated shampoo applications add time

Shampoo use produced the strongest result. Showers involving two or more shampoo applications lasted around 27% longer than those with just one lather.

Put simply, one wash took about five minutes, whereas two took around six and a half minutes. More than one in five showers involving hair washing included a second application.

“It turns out the biggest drivers of water use are not who you are or where you live. What matters most is what you actually do in the shower,” said Dr. Pablo Pereira-Doel.

“Small routines such as applying shampoo twice or letting the water run while lathering can extend shower time far more than people realize.”

Why pausing the water can have the opposite effect

Switching the water off while soaping up may seem an obvious way to reduce consumption.

Showers with one pause were marginally shorter, although the difference was too slight to be reliable.

However, showers with three or more pauses showed the reverse pattern. They were about 20% longer than showers with no pauses, and 28% longer than those with one pause.

The researchers interpreted repeated pauses as an indication of a leisurely, unhurried shower rather than a water-conscious one.

Soft water and younger adults

In areas with soft tap water, showers lasted roughly 23% longer than they did in hard-water areas.

Because soft water produces a richer lather, it may make standing in the shower more enjoyable.

Younger and middle-aged adults spent the longest in the shower.

Those aged 18 to 29 showered around 29% longer than people over 50, while people in their 40s showered about 31% longer.

What else made showers longer

Water-saving showerheads are designed to lower consumption by reducing water flow. In these households, though, they had the opposite outcome.

A flow restrictor was installed in only 13% of showers. These showers lasted an average of 5:51, compared with 4:38 for those without one.

When the flow is lower, people may remain under the shower for longer in order to feel equally clean or warm.

The researchers describe this as a rebound effect. It points to the same potential problem with any measure that reduces flow without changing the underlying habit.

Products may reduce water waste

The study received support from L’Oréal Research and Innovation and Ipsos, the market-research company that recruited the households.

This support is relevant because the paper’s recommendations return to product choices. Its findings indicate that changing products may be as important as changing behaviour.

Single-use formulations, clearer guidance on dosage and prompts that indicate when washing is complete could all help to cut water waste in the shower.

According to the study, rinsing shampoo from hair uses approximately 1.9 gallons (7.1 litres) of heated water. Conditioner uses about 1.7 gallons (6.3 litres).

Designing shower solutions around habits

All showers were recorded during one cold period, meaning the figures cannot show how routines change through the seasons.

Participants may also have showered somewhat differently because they knew a sensor was installed, although the extended study period probably reduced that effect.

For the hair-washing group, the team assessed one person in each household. This excludes how teenagers and younger children in the same home may shower.

Participants were not asked about stress, mood or feeling cold, each of which might lengthen a shower independently. Every household was also in Germany, so the same pattern may not apply in other countries.

“If we want to reduce household water consumption, we need to design solutions that work with people’s habits rather than against them,” said Pereira-Doel.

“Behavioral nudges, smarter feedback devices and better product design could all play a role in helping people use less water without sacrificing comfort.”