Drink water regularly, in small sips throughout the day to optimally support the kidneys. Stop drinking 2 hours before bed to avoid going to the toilet at night.
The kidneys filter blood continuously and work best when fluids are replenished at regular intervals rather than suddenly. Staying hydrated helps maintain blood volume and urine flow, aids in waste removal, and prevents kidney stones.
The US Centers for Disease Control and Prevention (CDC) and the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) recommend drinking water regularly throughout the day, adjusting to activity, temperature and personal health needs, instead of just focusing on the rule of drinking enough.
How to drink water to improve kidney health
Drink enough water every day: Each person should drink enough water, about 1.8-2 liters per day. Needs increase with heat, exercise and diet.
Preventing kidney stones: According to the American Urological Association (AUA), adults should drink enough water to produce at least 2.5 liters of urine per day, reducing the risk of kidney stones. This can only be achieved through regular rehydration from morning to night. Adding lemon juice to a glass of water helps replenish citrate, reducing the formation of some types of stones.
Sleep and nocturia: Drinking large amounts of water close to bedtime increases nighttime urination and disrupts deep sleep. You should divide the amount of water you drink equally and limit drinking water two hours before going to bed to support good sleep and reduce the number of trips to the toilet at night.
Avoid drinking too much water: Drinking too much water suddenly can dilute sodium in the blood, leading to hyponatremia. Drinking water slowly helps avoid this situation.
How to divide the amount of water evenly throughout the day
| Time | Recommended amount | Benefit |
| Morning (within 30-60 minutes after waking up) | 250-300 ml | Rehydrates after overnight dehydration and helps the kidneys filter waste |
| During every meal | About 250 ml | Supports digestion and maintains stable body moisture without causing bloating |
| Between meals | 150-250 ml every 60-90 minutes | Maintains urine flow to remove waste and prevent crystal buildup in the kidneys |
| When exercising or in hot weather | 150-350 ml every 20-30 minutes | Replenishes the amount of sweat lost, helping to balance electrolytes |
| Two hours before bed (2-hour rule) | Stop drinking water continuously, only take small sips (30-60 ml) if needed | Reduce nocturia and improve sleep, avoiding interruptions |
Tips for rehydrating at night to avoid going to the bathroom at night
- Drink water before eating: Try to drink 60-70% of your daily water consumption before 4:00 p.m.
- Avoid consuming caffeine or alcohol late at night: Both have a diuretic effect, increasing urine output.
- Elevate your legs after dinner (30-60 minutes): Helps redistribute accumulated water and reduce the need to go to the bathroom at 2 o’clock, very useful for the elderly.
How to know if you’re drinking enough water
Urine color: Light yellow means enough water, dark yellow means you need to drink more. Repeatedly clear urine can signal excess fluid.
Frequency of urination: Going to the bathroom 5-7 times during the day is normal. Too little means dehydration, too much at night means drinking late.
Symptom: Thirst, dry mouth or dizziness indicate you’re drinking too little. People who drink too much often experience bloating or nausea.