sipIT2: Improving Adherence to Fluid Intake Guidelines for Kidney Stone Prevention

Inclusion Criteria: * previous diagnosis of symptomatic kidney stone in past 5 yrs * 24-hr urine volume ≤ 2.0 L/day, * age 18 or older, * own iOS or Android smartphone, * proficient in English language, * capable of providing informed consent, and * willing to use a Fitbit smartwatch, connected water bottle, and mobile app for the study every day for a year, and receive text messages reminder to drink. Exclusion Criteria: * previous diagnosis with cystine stone, * pregnant or planning to become pregnant in the next 12 months, * concurrently participating in another study involving fluid intake or diet, * plan to have surgery or relocate outside the area within the next year * co-morbidities that preclude high fluid intake, conditions with high fluid losses (e.g., congestive heart failure, bariatric surgery, GI tract ostomy, short gut syndrome, chronic diarrhea including patients with ulcerative colitis/Crohn's disease, hyponatremia), or conditions that preclude ability to collect 24-hour urine (severe urinary incontinence), * active medical treatments that would impair protocol compliance, * chronic use of lithium, or * psychiatric conditions impairing compliance with the study protocol.