How Much Water Should Breastfeeding Mothers Drink? The Evidence-Based Answer

Breastfeeding places a unique demand on the body.

Breast milk is made up of approximately 87–90% water, and your body prioritises milk production — even if your own hydration is sub-optimal. The Australian Breastfeeding Association explains that breastfeeding significantly increases fluid requirements as the body continually draws on maternal reserves to make milk.

During breastfeeding, your body:

• Loses fluid daily through milk production
• Draws on electrolyte stores (especially sodium, potassium, and magnesium)
• Needs adequate blood and plasma volume to support milk flow

This is why thirst during breastfeeding often feels different to normal thirst — and why water alone doesn’t always resolve it.

Every day, your body:

• Produces ~750–800ml of breast milk
• Transfers ~650ml of water directly into that milk
• Manages higher energy and nutrient demands
• Regulates temperature differently due to hormonal shifts

Sleep deprivation and constant caregiving can also blunt thirst cues, meaning many mothers don't feel thirsty until dehydration has already started.

This is why understanding the early warning signs matters. For guidance on recognising dehydration before it affects your wellbeing or milk supply, read our guide on signs of dehydration in breastfeeding mothers.

Evidence-Based Guidelines

There's no single "perfect" number — but there are clear benchmarks.

Australian Guidance

• NHMRC: ~2.6 litres of total fluids per day
• Australian Breastfeeding Association: Drink to thirst, with awareness that needs increase during lactation

International Guidance

• Institute of Medicine (US): ~3.1 litres/day
• NHS (UK): Baseline intake plus additional fluids
• WHO: Drink to thirst, recognising increased needs

What "Total Fluids" Means

These targets include:

• Water
• Herbal teas
• Milk or plant milks
• Soups and broths
• Water-rich foods (fruit, vegetables)

Because roughly 20% of fluid comes from food, most breastfeeding mothers need around:

2–2.5 litres of drinking fluids per day
(around 8–10 large glasses)

Why "8 Glasses a Day" Often Isn't Enough

The "8 glasses" rule:

• Was never designed for lactation
• Doesn't account for milk production
• Ignores heat, activity, or night feeds

For breastfeeding mothers, 8 glasses is a baseline — not an upper limit.

The Most Reliable Indicator: Urine Colour

• Pale yellow → adequately hydrated
• Dark yellow / amber → increase fluids

Check mid-morning and mid-afternoon.

Other Helpful Signs

• Fewer headaches
• More stable energy
• Moist lips and mouth
• Regular bowel movements
• Consistent milk output

If several of these feel off, hydration is often the first place to adjust.

1. Waiting Until Thirst Hits

The Problem: Thirst cues can be delayed when you're sleep-deprived. By the time you feel thirsty, mild dehydration may already be present.

The Solution: Tie hydration to feeds instead. Keep a large water bottle (750ml-1L) at each nursing station and drink every time you sit down to nurse or pump.

2. Forgetting Night Feeds Count Too

The Problem: Skipping fluids overnight often leads to morning headaches and fatigue.

The Solution: Keep water beside your bed and sip during night feeds. This simple habit can prevent the morning dehydration many mothers experience after multiple nighttime nursing sessions.

3. Assuming "More Water = More Milk"

The Problem: Severe dehydration can affect milk supply — but drinking excessive water does not increase supply beyond what your body is already capable of producing.

The Solution: Aim for adequate hydration (meeting the 3.1L guideline), but don't force yourself to drink uncomfortably large amounts.

For a deeper explanation of the actual relationship between fluid intake and milk production, explore our guide on how hydration affects milk supply (and where the limit is).

4. Relying Only on Plain Water

The Problem: While water is essential, relying exclusively on plain water can lead to electrolyte imbalance, especially if you're drinking large volumes without adequate mineral intake.

The Solution: Balance plain water with mineral-rich fluids and foods. We'll explore this more in the next section.

5. Not Adjusting for Climate and Activity

The Problem: Fluid needs increase significantly in hot weather, during exercise, or if you're unwell (fever, vomiting, diarrhoea).

The Solution: Increase your baseline intake by 1-2 additional cups on hot days, after exercise, or during illness. Monitor urine colour as your primary guide.

Some breastfeeding mothers drink plenty of water but still feel:

• Persistently thirsty
• Light-headed or fatigued
• Headachy
• "Washed out"

This can sometimes point to electrolyte depletion, where fluids are present but minerals are low.

Understanding Electrolyte Balance

During lactation, your body:

• Transfers significant amounts of sodium, potassium, calcium, and magnesium into breast milk
• Loses additional minerals through increased metabolic activity
• May experience electrolyte depletion faster than non-lactating women

For a complete breakdown of which minerals matter most during breastfeeding and how they support both hydration and milk production, read our guide on electrolytes for breastfeeding mothers.

Natural Electrolyte Sources

You can support electrolyte balance through:

Food sources:

• Coconut water (potassium)
• Bone broth (sodium, minerals)
• Bananas (potassium)
• Leafy greens (magnesium, calcium)
• Dairy or fortified plant milk (calcium)
• Avocados (potassium, magnesium)

Hydration beverages:

• Mineral-rich hydration powders formulated for breastfeeding mothers
• Herbal teas with added electrolytes
• Homemade electrolyte drinks (water + pinch of salt + squeeze of citrus + honey)

Gentle Support If Water Isn't Cutting It

If plain water doesn't touch your thirst, mineral-balanced hydration support can help some mothers feel more stable — especially during heat, illness, or frequent feeds.

Consider a recovery hydration powder designed specifically for breastfeeding mothers that provides balanced electrolytes alongside hydration, particularly helpful for overnight replenishment.

You can explore the full range of gentle options designed for maternal hydration here.

You may need extra intake if you:

• Live in a hot or humid climate
• Exercise regularly
• Are unwell (fever, vomiting, diarrhoea)
• Breastfeed multiples
• Experience oversupply

Use urine colour — not rigid numbers — as your guide.

For practical strategies on staying hydrated during Australian summers or in hot climates, see our guide on managing hydration in heat while breastfeeding.

Yes, although it's uncommon.

Drinking very large amounts of plain water without adequate electrolytes can dilute sodium levels (a condition called hyponatremia).

Warning Signs

• Nausea
• Headache
• Confusion
• Swelling in hands or face

Balance matters more than volume. If you're drinking more than 4-5 litres of plain water daily and experiencing these symptoms, reduce your intake and consult your healthcare provider.

For most breastfeeding mums, the question isn’t water vs electrolytes, but when to use each.

A simple, realistic framework:

• Drink water regularly throughout the day
• Use electrolytes when thirst persists or energy drops
• Eat regular meals to support mineral intake
• Listen to your body — not rigid rules

Hydration should support you, not become another thing to “optimize.”

If hydration has felt confusing or inconsistent, start simple:

Immediate actions:

1. Aim for ~3.1 litres of total fluids daily
2. Drink at every feed — keep water bottles in every room where you nurse
3. Check urine colour twice a day — pale yellow is your target
4. Adjust intake during heat, illness, or cluster feeding

For deeper support:

• Return to our Motherhood Hydration 101: The Complete Guide for comprehensive hydration strategies across pregnancy, breastfeeding, and postpartum
• Learn how hydration impacts milk supply and where the actual limits are
• Understand which electrolytes matter most for breastfeeding mothers
• Recognise the early signs of dehydration before they affect your wellbeing
• Explore our breastfeeding hydration collection for mineral-rich options that support both hydration and recovery

Remember: hydration is a foundational element of breastfeeding success — not a complicated challenge to overcome. Small, consistent changes in your daily routine will make a significant difference in how you feel.