How Much Water Do You Actually Need?
Walk into any gym, office or school pickup and you’ll see it: the giant water bottle, refilled constantly, sometimes with times marked down the side telling you when each section should be finished. Hydration has become something to track and buy the right product for. Not every woman likes drinking plain water, and that’s fine.
Is 8 glasses a day the right target?
Not exactly, and it was never meant to be a one size fits all number. Major health bodies put total water intake, everything you drink plus food, somewhere between 2.0 and 2.7 litres a day for adult women. What you actually need depends on your own body weight, since that affects how much water you hold and how much you lose day to day. Research on women aged 40 to 70 found that good hydration tracked with roughly 40ml of total water per kilogram of body weight, which is a more useful way to think about your own range than aiming for a number that’s the same for everyone.
That total includes tea, coffee, milk, juice, soft drinks and alcohol, not water alone.
Does food count toward this?
Yes, and more than most people realise. Soup, ice cream, yoghurt, and fruit and vegetables high in water like cucumber, watermelon, oranges and tomatoes all contribute. Once you count these alongside your usual drinks, most women are closer to meeting their needs than a “did I drink 8 glasses of water” checklist would suggest.
What about pregnancy and breastfeeding?
Both increase what you need. Pregnancy adds roughly 300ml a day above your usual amount. Breastfeeding adds more, around 700ml a day, to cover what’s lost through breast milk. Research on pregnant women has found many fall short of these targets.
What does this have to do with bladder health?
Both too little fluid and too much affect your bladder.
Not drinking enough concentrates your urine, and concentrated urine irritates the bladder lining, which can make urgency and leakage worse.
Drinking well beyond what your body needs increases how often your bladder fills, which increases how often you feel the urge to go. Over time, this can train your bladder toward needing to empty more frequently, even at normal fluid levels.
A trial in premenopausal women with recurrent urinary tract infections found that adding 1.5 litres a day reduced how many infections they got and cut how often they needed antibiotics.
Caffeine and alcohol count toward your fluid total, but they can also irritate the bladder and increase urgency for some women.
REFERENCES
EFSA Panel on Dietetic Products, Nutrition and Allergies. (2010). Scientific opinion on dietary reference values for water. EFSA Journal, 8(3), 1459.
Sawka, M.N., Cheuvront, S.N., & Carter, R. (2005). Human water needs. Nutrition Reviews, 63(6 Pt 2), S30-39.
Stookey, J.D., Langthaler, P., Felder, T.K., et al. (2025). Hydration and health at ages 40-70 years in Salzburg Austria is associated with a median total water intake over 40 mL/kg including at least 1 L/d plain drinking water. Frontiers in Public Health, 13.
National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand: Water. Eat for Health.
Hooton, T.M., Vecchio, M., Iroz, A., Tack, I., Dornic, Q., Seksek, I., & Lotan, Y. (2018). Effect of increased daily water intake in premenopausal women with recurrent urinary tract infections: a randomized clinical trial. JAMA Internal Medicine, 178(11), 1509-1515..
Developed by the WHEN Clinical Team
Clinically reviewed by the WHEN Clinical Governance Committee
Last reviewed: 17/07/2026
With clinical input from Scott Marshall, Pharmacist, Pharmaceutical Advisor. Over 20 years of clinical pharmacy experience across Australia, the UK and Ireland.
With clinical input from Peta Titter, RN, Grad Cert Continence Nursing, Advanced Diploma of Pilates. Honours by Research (diastasis recti). PhD candidate, University of Tasmania. Founder and CEO, WHEN.
