The investigators have designed a randomized controlled trial to test whether increased water intake slows renal decline in patients with Stage-III Chronic Kidney Disease. Participants randomized to the hydration-intervention group will be asked to drink 1.0 to 1.5 L of water per day (depending on sex and weight), in addition to usual fluid intake, for one year. The investigators will calculate the change in kidney function (estimated glomerular filtration rate, measured every three months for 12 months), and compare renal decline between the intervention and control groups. The investigators hypothesize that increased water intake will slow renal decline.

Inclusion Criteria:

• Age 18-80 years
• Able to provide informed consent and willing to complete follow-up visits.
• Estimated glomerular filtration rate between 30 and 60 ml/min/1.73m2
• Trace protein or greater (Albustix) or urine albumin/creatinine ratio >2.8 mg/mmol (if female) or >2.0 mg/mmol (if male) from a random spot urine sample

Exclusion Criteria:

• Self-reported fluid intake >10 cups/day or 24-hr urine volume >3L.
• Enrolled in another trial that could influence the intervention, outcomes or data collection of this trial (or previously enrolled in this trial)
• Received one or more dialysis treatments in the past month
• Kidney transplant within past six months (or on waiting list)
• Pregnant or breastfeeding
• History of kidney stones in past 5 years
• Less than two years life expectancy
• Serum sodium <130 mEq/L without suitable explanation
• Serum calcium >2.6 mmol/L without suitable explanation
• Currently taking hydrochlorothiazide >25 mg/d, indapamide >1.25 mg/d, furosemide >40 mg, or metolazone >2.5 mg/d
• Currently taking lithium
• Patient is under fluid restriction (<1.5 L a day) for kidney disease, heart failure, or liver disease, AND meets any of the following criteria: i) end stage of the disease (heart left ventricular ejection fraction <40%, NYHA class 3 or 4, or end stage cirrhosis) or ii) hospitalization secondary to heart failure, ascites and/or anasarca
• Patient has GI disease (history of inflammatory bowel disease, Crohns, etc.)

Research staff and participants were aware of the randomized group assignment; however, outcome assessors (technicians performing the laboratory measurements for the primary and secondary outcomes) are blinded to the random allocation, and the trial statistician will be blinded to patient allocation for the primary analysis