High Fluid Intake Doesn’t Guarantee Fewer Kidney Stones, Study Finds

For decades, increasing fluid intake has been a cornerstone recommendation for preventing kidney stones. But, a recent randomized clinical trial published in The Lancet on March 21–27, 2026, challenges this long-held belief. The study found that a behavioral intervention program designed to promote high fluid intake did not significantly reduce the recurrence of symptomatic kidney stones, although it did modestly increase urine volume. Source

The Study Design

Researchers enrolled 12 years and older with a history of kidney stones and low 24-hour urine volumes at six academic medical centers across the United States. Participants were randomly assigned to either a behavioral intervention group or a control group receiving standard guideline-based care. Source

The intervention group received a fluid prescription, financial incentives for adherence, health coaching to address barriers to increased fluid consumption, and personalized approaches like text message reminders. Source The primary outcome measured was symptomatic stone recurrence – defined as stone passage or the need for a procedure – over a two-year follow-up period. Source

Key Findings

Despite the intensive intervention, the study revealed no statistically significant difference in symptomatic stone recurrence between the intervention and control groups. Source However, participants in the intervention group did demonstrate a modest increase in 24-hour urine volume compared to those receiving standard care. Source

Researchers also assessed secondary outcomes, including changes in urinary symptoms, radiographic stone recurrence or growth, and a composite measure of stone recurrence and growth. The study also monitored for hyponatremia requiring hospitalization as a safety endpoint. Source

What Does This Mean for Kidney Stone Prevention?

These findings suggest that simply increasing fluid intake, even with behavioral support and incentives, may not be enough to prevent kidney stone recurrence in all individuals. Although adequate hydration remains an important part of overall health, this study highlights the complexity of kidney stone formation and the need for a more personalized approach to prevention. Source

Other factors, such as diet, genetics, and underlying medical conditions, likely play a significant role in kidney stone development. Further research is needed to identify the most effective strategies for preventing these painful and often recurrent conditions.

Frequently Asked Questions

Is drinking more water still important?

Yes. While this study shows increased intake doesn’t guarantee prevention, staying hydrated is crucial for overall health and can contribute to kidney function.

What can I do to prevent kidney stones?

Talk to your doctor about your individual risk factors and develop a personalized prevention plan. This may include dietary changes, medication, and monitoring of urine composition.

Are there other ways to prevent kidney stones besides drinking water?

Yes. Dietary modifications, such as reducing sodium and animal protein intake, and increasing citrate consumption, can be helpful. In some cases, medications may be prescribed to reduce stone formation.