Is four minutes in the shower enough to get clean?

Looking forward to a long soak after being outside in the sun, surf and sand - or to warm up? Council recommendations to keep daily showers down two to four minutes to conserve water is not always easy.

"I mean four minutes is a long time, right?" says Navy Warrant Officer Darren Crosby. Like other sailors, Crosby has been trained to spend two to five minutes in the shower - always aware of conflict, restrictions or malfunctions onboard ships.

He says officers around the world are known for their quick showers - getting wet in 30 seconds, shutting off the water to lather or scrub, then rinsing off in a minute or so. It's become a technique people often refer to when talking about saving water and energy.

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While the Navy prove it's possible to do, one does wonder how clean a regular person can get in a four-minute shower.

Auckland-based dermatologist Vania Sinovich, who runs The Skin Company clinic, says experts widely agree three to four minutes in the shower is more than enough to maintain hygiene - if you focus on areas like the armpits, groin, feet and the scalp, where oil and dirt tends to build up.

Long hot showers strip your skin of its natural oils and disrupt the skin barrier, which can lead to dryness, itchiness and irritation, she says. It can also harm the microbiome - the collection of good bacteria that protects your skin.

"A thorough rinse with warm water paired with gentle cleansing products is usually sufficient for hygiene.

"The goal should be efficient cleansing rather than scrubbing every inch of your body daily."

Hair stylist Sean Mahoney, who has more than 20 years of experience under his belt including at K Road's Colleen salon, says it takes two to five minutes to wash clients' hair, but each person has different needs depending on how much dirt they get in there and their hair type.

But generally, you wouldn't need to wash your hair every day of the week - about twice is usually enough, he says. A dry shampoo powder might be great if you're looking to extend the time before you wash your hair again.

Here are his tips to cut back time spent on washing hair:

Try a low-foaming shampoo or a soap-free body wash, Dr Sinovich says. Exfoliators and detangling products may mean you'll spend more time in the bathroom.

"Opting for less foamy, pH-balanced cleansers-like cream cleansers or soap-free products-can actually improve your skin health without compromising cleanliness.

"Using such products may also reduce the time you spend scrubbing, as they cleanse efficiently without needing excess lather or vigorous washing."

There are also multitask or two-in-one products that can wash both your hair and body, she says.

Cold water can effectively wash dirt, sweat, and bacteria, Dr Sinovich says. There are some benefits too - the cool water helps preserve the skin's natural oils and prevent over-drying. For hair, cool water can help seal the cuticle, leaving it smoother and shinier, she says.

"However, cold water might not be as effective for breaking down oils, especially on the scalp or in greasy areas of the skin. If your goal is a deeper cleanse, lukewarm water is a better choice, as it strikes a balance between comfort and efficacy."

Navy members have to consider that their water supply is also used to run things like refrigerators, air conditioning and toilets, Crosby explains.

He recalls a few years ago when they were under tight water restrictions and had to get through as many people as possible in the showers in a short time.

"For example, someone would hop in the shower, turn the water on, lather up, get out. Someone else will hop in and do the same process, and then you just swap, you know, sort of rotate it around one shower or mini showers.

"On another occasion for about two months … [we did] what we call the bird bath, where you just turn on, fill up the basin of water and that was your shower."