Enjoying my first mouthful of wine after drinking only water for 10 days, I tasted subtle flavors I'd never noticed, from every individual grape that went into making it. As I stood in a girlfriend's kitchen, with a glass of rose, I realized my tastebuds had been completely reset. Water no longer tasted metallic, and wine tasted like ambrosia.

What is a "beverage cleanse"?

I spent 10 days drinking nothing but plain water from the tap or filtered water from a jug. No tea, no coffee, no alcohol, soda, or even sparkling water. Not even a slice of lemon. I ate normally and carried a small bag of chocolate-covered coffee beans for emergencies, because feeling weary is one thing, but falling asleep and ending up on the last stop of the metro is quite another.

The idea came about when I was visiting London during a summer vacation. I was on an Underground train when I noticed the "H2Only" campaign to raise funds for the Royal National Lifeboat Institution—a volunteer organization that saves lives along the British coastline.

While I applaud the RNLI's mission, which echoes that of the volunteer lifeguards seen on Australian beaches, I deeply wanted to make a healthy change. This seemed like the perfect opportunity to help others and keep myself accountable.

The water diaries.

On the first full day, I had a headache that became a constant companion. I took painkillers to dull it. At times, I thought I'd fall asleep standing up. By the third day, my energy levels started to level out and the headache started to abate. I no longer experienced the highs and lows of my usual caffeine-fueled days; I felt, to use a lifeboat term, on an even keel.

I also realized I use cups of tea and coffee as rewards for myself, as punctuation for my day, and as ways to procrastinate.

Why was everyone else in the city constantly drinking coffee, no matter what time of day or night? I would look around for the nearest glass of water, and it was invariably empty. I lost track of how much I was drinking, but it was a serious volume.

By Day 5 or 6, I felt less scatterbrained than I normally do. I was able to recall fleeting thoughts and act on them.

Towards Day 8, I started noticing my sense of smell and taste had sharpened considerably: I was like a child, with strong likes and aversions, no longer experiencing the mediocre ambivalence to flavor that has come with middle age.

Drinking so much water, and nothing else, also reduced my appetite. I ate less, less often, and I felt full after eating smaller amounts, something that was quite new to me.

I thought I would miss an evening glass of wine, or cocktail, but what I would have given anything for was a Saturday morning pot of tea.

The cultural implications of drinking only water.

After six and a half years of living in the states, and much to my own surprise, I have turned into a committed cold brew coffee drinker. But having grown up in Australia, and as the daughter of two New Zealanders, my dedication to tea remains lifelong and unwavering.

I usually start the day with a cup of tea, at a time when I can barely focus. That gets me through until I've done my morning tasks and the school drop-off, then I switch to coffee. Just one, or sometimes two, and never after midday. For an afternoon pick-me-up, it's tea all the way, English style and preferably from a pot.

Then as evening approaches, it's time for a wine, a beer, or a cocktail, depending on the occasion. I'd aim for a couple of AFDs (alcohol-free days) per week, but when you're tired, discipline is in short supply.

But for 10 days it was water, so much water. Initially I felt bloated yet with a barely quenchable thirst. I would feel panicky if I didn't have a bottle of water in my bag or access to a drinking fountain. This leveled out after a few days, at the same time as my skin plumped up, my eyes cleared, and I managed to stay awake through the daylight hours.

Checking in with my British counterparts on a daily basis, I saw that others in the group reported misplacing five, six, or more pounds during the 10 days, yet I had no such experience.

When it was over, many of my fellow H2Onlies were horrified to find they no longer even liked the taste of tea, coffee, or soda. One posted: "Nothing has any flavour—not even espresso! WHAT FRESH HELL IS THIS?"

It truly felt like my individual cells had been flushed out, on a microscopic level. Such a simple change, despite the discipline involved, made an astonishing difference in how I felt. As a result, I am now a committed water addict, and I don't think I'll ever give it up.

But I'll take a glass of red, if you're pouring one.