Are You Actually Hydrated?

Let’s Talk About the 3 Litres a Day Rule

You’ve heard it a hundred times. “Drink 3 litres of water a day.” “Eight glasses minimum.” “More is better.” And then you look at your day — the morning coffee, the sambar rice for lunch, two cups of tea, a glass of buttermilk, a bowl of rasam, a cucumber, some watermelon — and wonder if any of that counts. Or if you really do need to force down three separate litres of plain water on top of everything else.

Here’s the honest answer, and it’s more nuanced than the internet lets on. Your body needs approximately 2.5 to 3 litres of total fluid intake per day if you’re an average adult. But ‘fluid intake’ does not mean plain water alone. It means everything hydrating that goes into your system — and in the Indian diet, that’s a surprising amount.

Let’s decode where hydration actually comes from in your day — and how to make sure you’re meeting your needs without feeling like you’re force-feeding yourself water.

Why Hydration Matters — a Urologist’s Perspective

As a urologist, I see the consequences of chronic under-hydration in my clinic every single week. Kidney stones forming quietly over years, then arriving with excruciating pain. Recurrent urinary tract infections in women who don’t drink enough during a busy workday. Bladder irritation, urinary frequency, and prostate discomfort in men, all made worse by inadequate fluid intake. Concentrated dark urine, cloudy days of feeling generally unwell.

Most of this is preventable. Not with a supplement, not with a fancy filter, not with a trending drink. With adequate, consistent, daily hydration. Your kidneys filter about 180 litres of blood a day. Your bladder collects and releases roughly 1.5 to 2 litres of urine over 24 hours. Every part of this system runs on water. When you give it enough, it looks after you quietly and efficiently. When you don’t, it will eventually let you know — and rarely gently.

Hydration is about the whole day, not just the water bottle. What you eat contributes to it. What you drink contributes to it. And a few habits can make it effortless.

Where Your Daily Hydration Actually Comes From

Here’s a realistic breakdown of common hydration sources in an Indian household — and how much each contributes:

Source	Approx. Hydration	Notes
Plain water (1 glass = 200 ml)	200 ml	The gold standard; aim for majority of daily intake
Buttermilk / Chaas	180 ml	Excellent — hydrating, cooling, gut-friendly
Coconut water (tender)	200 ml	Naturally rich in electrolytes; ideal in Chennai heat
Rasam / Clear soup (1 bowl)	200 ml	Hydrating and mineral-rich — counts fully
Milk (1 glass)	180 ml	Counts as hydration — also protein and calcium
Curd rice / Dal / Sambar rice	100 ml/bowl	Water-rich meals contribute more than we realise
Fresh fruit juice (unsweetened)	150 ml	Counts — but limit to one glass; whole fruit is better
Tender fruits (watermelon, orange, muskmelon)	150 ml/cup	Water-dense fruits count meaningfully
Cucumber, tomato, bottle gourd, ash gourd	100 ml/cup	‘Water vegetables’ hydrate as they nourish
Herbal / lemon water / infused water	200 ml	Adds variety; no calorie load
Tea / Coffee (1 cup)	50–80 ml net	Mild diuretic — subtracts a little; drink water alongside
Aerated / sugary drinks	0 (net)	Do not count — dehydrating, sugar-loaded, best avoided
Alcohol	Negative	Actively dehydrating — pair 1 glass of water per drink

Notice something important? Between your rasam, buttermilk, sambar rice, tender coconut, cucumber salad, morning milk, and fruits — you could easily be getting 1.5 to 2 litres of hydration from food and non-water sources alone. Which means your plain water target may only need to be 1 to 1.5 litres, not the 3 litres many people struggle with.

A practical Indian rule: 6 to 8 glasses of plain water (about 1.2 to 1.6 L), plus everything else you’re already eating and drinking, is enough for most healthy adults.

How Many Glasses? a Simple Way to Track

One standard Indian steel tumbler holds about 200 ml. So a target of 1.6 to 2 litres of plain water = 8 to 10 tumblers per day. Here’s a natural way to space them out through the day without thinking too hard about it:

On waking: 1 glass — the most important one, rehydrates after 8 hours of sleep
Mid-morning (after breakfast): 1 glass
Before lunch: 1 glass
Post lunch (30 min later): 1 glass
Mid-afternoon: 1 glass
Evening / with tea: 1 glass
Pre-dinner: 1 glass
Before bed: 1 glass — helps overnight recovery

That’s 8 glasses = 1.6 L, effortlessly, without carrying a giant water bottle everywhere.

The Smart Phone / Smart Watch Hack

If you’re one of those people who genuinely forgets to drink water — you’re not alone, and your phone can absolutely fix this for you.

Setting Reminders That Actually Work

On any smartphone (Android or iPhone): Set 6 to 8 gentle alarms across the day — 7 AM, 9 AM, 11 AM, 1 PM, 3 PM, 5 PM, 7 PM. Label them ‘Water’ or use a water drop emoji so you know why they’re buzzing.
Dedicated hydration apps: WaterMinder, Plant Nanny, and Hydro Coach are excellent — they let you log intake, adjust goals, and send smart nudges based on your day.
On Apple Watch / Samsung Galaxy Watch / Fitbit: Set hourly ‘Stand + Sip’ vibrations. The tiny wrist buzz breaks focus and reminds you without disrupting work.
Google Fit / Apple Health: Both have built-in hydration logging — you can even track by cups, not millilitres.
Simple analog hack: Fill a 1-litre bottle in the morning. Aim to finish it by 2 PM. Refill for the afternoon. Two bottles a day = 2 litres. Done.

Pro tip: Place a filled glass of water on your bedside table before you sleep. That’s tomorrow’s wake-up glass, ready to go. Small ritual, huge difference.

Special Considerations — Diabetics

Hydration is particularly important for people with diabetes — dehydration raises blood sugar levels, and high blood sugar in turn causes more urination and dehydration. It’s a cycle worth managing carefully.

What to Choose

Plain water is the best possible choice — zero sugar, zero calories, full hydration
Buttermilk (unsalted or lightly salted) — excellent, low glycaemic index, high in probiotics
Coconut water in moderation — natural but does contain sugars; 100 ml, not a full glass
Herbal teas, jeera water, methi water — all diabetes-friendly and hydrating
Water-rich vegetables and low-GI fruits like watermelon (small portions), cucumber, and tomato

What to Limit or Avoid

Fruit juices — even fresh, unsweetened juice spikes blood sugar rapidly
Aerated drinks and packaged juices — completely avoid
Sweetened milk drinks, badam milk, milkshakes, flavoured yoghurt
Excessive tea or coffee with sugar — the sugar adds up quickly

Safety Warning — Kidney and Cardiac Patients

IMPORTANT: If you have chronic kidney disease, kidney failure, or are on dialysis, you are likely on a fluid restriction prescribed by your nephrologist — typically 800 ml to 1.5 L per day, sometimes less. The general ‘3 litres’ advice does NOT apply to you. Similarly, patients with heart failure, severe hypertension, or certain cardiac conditions are often on strict fluid restrictions to prevent fluid overload, breathlessness, and swelling. Please follow the specific limit set by your treating doctor and do not adjust it based on general wellness advice from any blog, influencer, or well-meaning family member.

For everyone else on any long-term medication or with a chronic health condition, it’s always worth asking your doctor once: ‘How much fluid should I be drinking daily, given my condition?’ A one-minute conversation can prevent months of unnecessary worry — or unintentional harm.

Hydration for Children — It’s Weight-Based

For children, we don’t use adult numbers. Their fluid needs are calculated by body weight using a standard paediatric formula — the Holliday-Segar method.

Child Weight	Daily Fluid Needed	Formula
Up to 10 kg	100 ml per kg	10 kg = 1000 ml (1 L)
10 to 20 kg	1000 ml + 50 ml per kg above 10 kg	15 kg = 1000 + (5×50) = 1250 ml
Above 20 kg	1500 ml + 20 ml per kg above 20 kg	25 kg = 1500 + (5×20) = 1600 ml
Teens (over 40 kg)	2 to 2.5 L per day	Similar to adult range; more in summer

A quick note: for children, milk, buttermilk, tender coconut, rasam, and dal all count towards this total — not just water. In fact, children often meet a large portion of their daily needs through these. Do not force water on a young child who is already drinking milk and eating well. Encourage water at meals and between play sessions, and keep it always accessible.

Warning signs of dehydration in children — fewer wet nappies, dark yellow urine, dry lips, lethargy, or crying without tears — need prompt attention.

Workouts, Sweaty Days, and Chennai Weather

If you’re exercising, playing sports, or simply surviving a Chennai April, your fluid needs go up — sometimes significantly. Here’s how to adjust:

During a Workout

Before workout: 300–500 ml water in the 30 minutes leading up to it
During workout: 150–250 ml every 15–20 minutes if the session is longer than 45 minutes
After workout: 500–750 ml water within the first hour, ideally with a pinch of salt and lime, or coconut water — to replace lost electrolytes

On Sweaty, Hot Days

Add 500 ml to 1 L extra water on top of your regular intake
Include electrolyte sources: coconut water, buttermilk with a pinch of salt, ORS, or nimbu paani with salt and sugar
Watch your urine colour: pale straw yellow = well hydrated; darker means drink more; almost clear = you may be over-hydrating
Don’t wait for thirst: in extreme heat, thirst is a late signal — you’re already mildly dehydrated by then

Chennai-specific tip: If you spend time outdoors between 11 AM and 4 PM in summer, one tender coconut a day is worth its weight in gold. Naturally electrolyte-rich, low-calorie, and perfectly suited to our climate.

Signs You’re Well Hydrated

Instead of obsessing over the exact number, watch for these signals from your body:

Urine is pale straw yellow — not dark, not clear
You’re urinating comfortably 5 to 7 times per day
Skin is supple, not dry or flaky
Lips are soft, not cracked
You feel alert, not sluggish or headachy in the afternoon
Bowel movements are regular and easy

If most of these check out, you’re doing beautifully. If several don’t, it may be time to look at your hydration habits more closely.

The Real Takeaway

Hydration is not a numbers game to obsess over. It’s a rhythm to build into your day. In the Indian household, you’re getting hydration from more sources than any Western guideline accounts for — rasam, buttermilk, watermelon, tender coconut, curd rice, sambar. Add 6 to 8 glasses of plain water on top of that, adjust up for workouts and heat, adjust down (with medical advice) if you have kidney or cardiac issues, and calculate carefully by weight for children.

That’s it. That’s the whole science.

Stay Connected With us

If you found this useful and want more honest, everyday health guidance — kidney health, urinary care, men’s and women’s urology, and overall wellbeing — follow Dr. Griffin M. and Ray & Rio Speciality Clinic for weekly content designed for real Indian lives.

And if you’re dealing with a specific urological concern — recurrent UTIs, kidney stones, prostate health, urinary flow issues, or anything else you’ve been putting off — book a consultation with Dr. Griffin M. We’re here to help, without hype.