Lemon water, citrate and how much to drink
By Oliver Silen · Updated November 2, 2026 · Not medical advice
Drink enough to make at least 2.5 liters of urine a day. That's the first line of the American Urological Association's guideline for every stone type [1], and it matters more than any single food.
How much water
The target is urine out, so the amount you drink is higher, often 3 liters or more, and more in heat or with exercise. Pale yellow urine through the day is a rough check. A 24-hour urine test measures it exactly.
How much lemon
Citrate in urine blocks calcium crystals from growing. In the trial most people cite, 12 stone formers with low urine citrate drank 4 oz (half a cup) of reconstituted lemon juice mixed into 2 liters of water, spread through the day. Urine citrate rose from 142 to 346 mg a day on average, and 7 of the 12 reached normal levels [2]. That's a lot more lemon than a slice in a glass.
Lemon itself is low in oxalate: lemon (grade A, 3.3 mg per 1 lemon). Bottled sweetened lemonade is a different drink: lemonade (grade C, 22 mg per 12 oz glass).
Acidic drinks wear tooth enamel, which several people on stone forums report. Drinking through a straw, with meals, and rinsing with plain water afterward are the usual dentist advice.
Potassium citrate
The guideline recommends prescription potassium citrate for recurrent calcium stone formers with low or relatively low urine citrate [1]. It's a medicine, so take it on a doctor's advice, especially with kidney disease or drugs that raise potassium. Over-the-counter potassium pills in the US usually hold 99 mg of potassium or less, far below a prescription dose.
Which drinks
In three cohorts of 194,095 people, coffee, tea, beer, wine and orange juice were linked with fewer stones, and sugar-sweetened cola and punch with more [3]. See coffee, tea and kidney stones.