Can drinking water prevent kidney stones? For most people, yes—adequate hydration is the #1 evidence-backed step to lower the risk of kidney stones, and it’s even more helpful for stopping stones from coming back. When people ask can drinking water prevent kidney stones, the answer is grounded in basic kidney physiology: when you drink enough water, you make more urine. More urine means stone-forming chemicals like calcium, oxalate, and uric acid are more spread out (diluted). That lowers “crowding” in the urine, so crystals are less likely to stick together and grow into a kidney stone. Many studies point to a practical goal of about 2–3 liters per day (8–12 cups), with higher needs in heat or heavy sweating. This guide explains the science, the best targets, tap vs bottled water, smart drink choices, and simple ways to stay on track.
Why hydration works (the science in plain English)
Kidney stones are hard deposits made from minerals and salts that come out of urine and form crystals. The most common type is calcium oxalate. Think of your urine like a glass of water with salt stirred in. If there’s too little water, the salt can stop dissolving and start to clump. Your kidneys face the same problem.
Urine dilution & supersaturation: the core mechanism
Your urine always has dissolved particles in it—calcium, oxalate, uric acid, phosphate, and more. When you’re dehydrated, you make less urine, so those particles get concentrated. At a certain point, the urine becomes “supersaturated,” which means there is more dissolved material than the liquid can comfortably hold. That’s when crystals can form. Those crystals can turn into a stone if they keep growing.
When you increase fluid intake, you raise urine volume. This lowers the concentration of stone-forming particles and reduces supersaturation. In simple terms, can drinking water prevent kidney stones comes down to dilution: more water means less concentration, and less concentration means fewer crystals forming in the first place.
This is also why can lack of water cause kidney stones? is such an important question. Low water intake is one of the most common and fixable causes of concentrated urine, which is a major driver of kidney stone formation.
What changes in urine when you drink more (volume, citrate, pH)
When you hydrate well, several helpful things can happen:
You produce more urine across the day and night. That matters because stones often start forming when urine sits concentrated for long stretches, like overnight. More urine also helps “flush” tiny crystals out before they grow.
Hydration can also support higher urine citrate in some people. Citrate is a natural blocker that helps keep calcium from binding tightly to oxalate or phosphate. It’s one reason citrus drinks (without too much added sugar) are often discussed in kidney stone prevention.
Urine pH (how acidic it is) matters most for certain stone types. People with uric acid stones often have urine that’s too acidic, which helps uric acid crystallize. Water alone may not fix pH, but good hydration still lowers concentration. In some cases, bicarbonate-rich mineral water or diet changes can help raise pH, but that should be personalized with a clinician, especially if you have other health conditions.
Stone types affected (calcium oxalate vs uric acid vs others)
Hydration helps with most stone types because dilution is a universal benefit, but the “extra steps” depend on what kind of stone you form.
Calcium stones (especially calcium oxalate) are the most common. Dilution reduces the chance calcium and oxalate will meet in high enough amounts to crystalize. Many people assume calcium in food causes stones, but low dietary calcium can sometimes worsen risk because more oxalate may be absorbed. Hydration is still the foundation either way.
Uric acid stones respond strongly to higher urine volume, and they also respond to raising urine pH (making it less acidic). Hydration helps, but some people also need medical guidance to change urine chemistry.
Struvite stones are often linked to urinary tract infections. Water supports urinary flow, but infection control is the key.
Cystine stones are rare and caused by a genetic condition. People with cystine stones often need very high urine volume goals and medication. Hydration still matters, but it may not be enough on its own.
Visual: concentrated vs dilute urine and crystal formation
When water intake is low, urine becomes concentrated and total urine volume drops. The same substances that are normally present in urine—such as calcium, oxalate, and uric acid—are packed into a smaller amount of liquid. This makes it more likely for particles to collide, stick together, and form crystals. Over time, these crystals can grow and combine, eventually developing into a kidney stone.
With good hydration, urine is more dilute and overall volume increases. Those same particles are spread out in a larger amount of fluid, so they are less likely to meet and bind together. Crystal formation becomes less likely, and any tiny crystals that do form are more easily flushed out of the urinary tract instead of staying behind to grow.
If you’ve ever gone most of the day with only a small bottle of water, then noticed your urine got dark yellow, you’ve seen this effect in real life.
Evidence: how much water lowers stone risk (data-first)
You don’t need perfect habits to benefit. The research shows a clear pattern: higher total fluid intake is linked to fewer stones.
Cohort data (primary prevention): dose-response benefits
Large population studies that follow people for years show a steady trend: more fluid, fewer stones. These studies consistently support the idea behind can drinking water prevent kidney stones, even though they are observational.
In a long follow-up of 51,529 men over 14 years (Health Professionals Follow-up Study), people drinking more than 2.5 liters/day had a significantly lower risk than those drinking less than 1.2 liters/day.
In a large cohort of 90,000+ women (Nurses’ Health Study I), those drinking more than 2.5 liters/day had 116 cases per 100,000 person-years, compared with 232 cases in those drinking less than 1.4 liters/day—about double.
These numbers line up with what many urology clinics tell patients: hydration is one of the most effective ways to avoid kidney stones.
RCT/meta-analysis (recurrence prevention): strongest evidence
The best proof comes from studies in people who already formed stones (secondary prevention). In this group, higher water intake clearly reduces the chance of another stone.
A systematic review of randomized trials found that higher fluid intake lowered recurrence with a risk ratio of RR 0.45 (95% CI 0.24–0.84). Put in plain terms, that’s roughly a 55% relative reduction, and about 149 fewer recurrences per 1,000 people over 5 years in some analyses.
Trials also showed a longer time before stones came back, with HR 0.40 (95% CI 0.20–0.79).
A broader meta-analysis of multiple trials has also reported that drinking around “8 cups/day” can reduce repeat stones, though individual needs vary.
If you’ve had a stone before and you’re asking, “Can drinking more water stop kidney stones from coming back?” the evidence-based answer is yes—especially when your goal is consistent urine volume day after day.
Limitations & what research can’t prove yet (no primary-prevention RCTs)
You may wonder: why not run a large randomized trial in people who never had stones? The main issue is time and cost—stones can take years to appear, and it’s hard to control what people drink for that long. So for first-time prevention, we rely on cohort studies and what we know about urine chemistry.
Also, hydration isn’t the only factor. High sodium intake, low citrate, certain metabolic issues, and genetics can keep risk high even when you drink a lot. Water is still a major lever, but it’s not magic.
Visual: mini evidence table (RCT vs cohort) + confidence notes
| Evidence type | What it answers | Key finding | How confident? |
| Cohort studies (men/women followed for years) | Does higher drinking reduce first-time stones? | >2.5 L/day linked to much lower stone rates than low intake | Moderate (association, not randomized) |
| Randomized trials (prior stone formers) | Does higher drinking prevent recurrence? | Recurrence reduced: RR 0.45; longer time to recurrence: HR 0.40 | Higher (randomized), but some studies are small |
How much should you drink to prevent kidney stones?
Most people want a simple rule like “8 glasses a day.” That’s a decent start, but stone prevention is better measured by urine output and consistency.
Practical target: aim for 2–3 L/day (and urine output goals)
A common target to help prevent kidney stones is 2–3 liters of fluid per day, which is about 68–101 ounces. So if you’ve been asking, “How many ounces of water a day to prevent kidney stones?” this range is a solid evidence-based starting point.
Many stone clinics also aim for urine output of at least about 2 liters/day. You can drink 2–3 liters and still not hit that if you sweat a lot, which is why adjustment matters.
If measuring liters sounds annoying, try this simpler approach: aim for pale yellow urine most of the day, and avoid long stretches of dark yellow urine. It’s not perfect, but it’s a practical feedback tool.
Adjusting for climate, sweat, work, and exercise (personalized hydration)
Your amount of water needs change based on how much water you lose.
If you work outside, live in a hot climate, or exercise heavily, you can lose a lot of water through sweat. In those cases, 2–3 liters may be too low. On days you’re sweating, it’s normal to need an extra 0.5–1.5 liters or more.
If you’re someone who “forgets to drink” and then tries to catch up at night, watch out. Big evening intake can help, but spacing your drinking through the day usually works better, including a glass of water in the evening so your overnight urine is not extremely concentrated.
On the other hand, if you have chronic kidney disease (CKD), heart failure, or you take medicines that affect fluid balance, you may have a fluid limit. For those people, “more water” is not always safe. Stone prevention should be guided by your clinician.
How much water should I drink a day to prevent kidney stones?
Most adults aiming for kidney stone prevention do well starting at 2–3 liters per day (68–101 ounces), then adjusting higher for heat, sweating, or frequent exercise. A strong sign you’re close to the right amount is making plenty of light-yellow urine across the day.
Interactive tool: hydration + urine-volume goal calculator (simple version)
You can estimate a daily goal with a few inputs. This is not medical advice, but it helps you pick a realistic target.
Hydration goal estimator (quick guide):
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Start with 2.3 liters/day (about 78 oz).
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Add 0.5 liters (17 oz) if you do 30–60 minutes of exercise or active work.
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Add 0.5–1.0 liters (17–34 oz) if it’s a hot day or you sweat heavily.
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If you have a history of kidney stones, aim toward the upper end and focus on steady intake all day.
If you want a real answer for your body, ask for a 24-hour urine test. It tells you actual urine volume and key minerals in your urine, which is more useful than guessing.
Tap water vs bottled water: does the type matter?
Most of the time, the best water is the water you will actually drink. Still, many people ask whether tap water is better or worse than bottled water for stones, and whether minerals in water matter.
NHANES finding: higher tap water intake tied to lower odds
In a U.S. analysis of 10,246 adults, higher tap water intake was linked to 32% lower odds of kidney stones (adjusted odds ratio 0.678). In that analysis, bottled water did not show a clear protective association.
This does not mean bottled water “causes” stones. It may mean that people who drink more tap water simply drink more total water, or that tap water minerals play a role, or that the bottled water group had different habits. Still, it raises a reasonable question: could certain minerals in water be helpful?
Possible reasons (minerals like calcium/magnesium; bicarbonate-rich water & uric acid)
Some tap water contains magnesium and calcium in small amounts. Magnesium can bind oxalate in the gut and may lower oxalate absorption for some people. Water with bicarbonate (more alkaline) could help people prone to uric acid stones by raising urine pH a bit.
That said, minerals in drinking water are usually much smaller than what you get from food. So think of this as a potential bonus, not the main strategy.
What to consider locally (hardness, filtration, safety reports)
If your local tap water is safe and you like the taste, it’s often the cheapest way to maintain high intake. The World Health Organization（WHO） says that access to safe drinking water is essential for health, and properly treated tap water is generally safe to drink in many regions, making it a practical choice for long-term hydration.
If you dislike the taste or worry about safety, filtration can help. Many people ask about reverse osmosis systems, so let’s cover that clearly.
How does the RO membrane work? Reverse osmosis (RO) pushes water through a very fine membrane. The membrane blocks many dissolved solids and impurities, so the filtered water has fewer minerals. This can improve taste and reduce certain contaminants, depending on your system and water source.
Is reverse osmosis water bad for you or your kidneys? For most healthy people, no—RO water is safe. The main downside is that it removes minerals that some people like for taste, and it can be more expensive and waste more water than simpler filters. From a stone viewpoint, what matters most is total hydration and urine output, not whether your water contains a little more or less calcium or magnesium.
Is reverse osmosis worth it? It can be worth it if it helps you drink more water because it tastes better, or if you have a known local water quality issue that the system addresses. If it makes you drink less because you dislike the taste, it’s not helping your stone risk.
For safety details, check your local water quality report and public health guidance.
Best fluids for kidney stone prevention (and what to limit)
Water is the main player, but it’s not the only fluid that “counts.” If plain water feels boring, you still have options.
Water is best—but what else “counts” toward fluids?
Most non-alcoholic fluids increase urine volume. Tea and coffee can count, especially if they help you reach your total. Milk, broth, and diluted juices add fluid too. The goal is steady urine flow, not forcing yourself to drink only plain water.
Still, some drinks can raise stone risk because of sugar, sodium, or certain additives. So it’s not just “any liquid is fine” if stones are a problem for you.
Citrate boost: lemon/lime additions (how to use it without excess sugar)
Citrate can help prevent calcium stones by binding to calcium and slowing crystal growth. A simple approach is adding lemon or lime juice to water. You don’t need a huge amount, and you don’t need sugar.
A practical pattern many people stick with is one bottle in the afternoon with lemon, then plain water the rest of the day. If you use citrus juice, try to keep it unsweetened or lightly sweetened, because high sugar intake can raise stone risk in some people.
Orange juice can raise citrate too, but it also has more sugar and calories, so portion matters. If weight or blood sugar is a concern, stick with water plus a small amount of lemon or lime.
Drinks to limit: sodium-heavy, sugary, dark cola; “fizzy drinks” caveats
Sugary drinks can increase stone risk in several studies, and they don’t help your kidneys in other ways either. Dark cola is often singled out because it may contain phosphoric acid and is linked to higher stone risk in some research patterns. Also watch sports drinks—some are high in sodium and sugar. They have a role during long, sweaty exercise, but they’re not a good everyday hydration base for most people.
People also ask about tea. Tea can count toward fluid, but very strong iced tea can be high in oxalate. If you drink large amounts daily and you form calcium oxalate stones, discuss it with your clinician and consider balancing with calcium-containing foods at meals and increasing water.
Visual: “Best vs Worst beverages” comparison table
| Drink | Helps with hydration? | Stone-related notes |
| Water | Yes | Best baseline for most people |
| Water + lemon juice | Yes | Adds citrate without needing sugar |
| Coffee / tea | Usually yes | Can count toward fluids; very strong tea may raise oxalate |
| Milk | Yes | Dietary calcium can be helpful with meals for many stone formers |
| Sugary soda | Not ideal | Sugar linked to higher risk; cola often best to limit |
| High-sodium drinks | Not ideal | Sodium can increase urine calcium in many people |
Step-by-step prevention plan (habits that improve adherence)
Knowing the goal is one thing. Hitting it on a busy day is another. If you’ve ever gotten to 4 p.m. and realized you’ve had only one cup of water, you’re normal.
A daily hydration routine (morning-to-evening schedule)
Here is a simple routine that works for many people because it spreads intake out. Use it as a starting point and adjust to your schedule.
Step-by-step daily plan
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Drink 12–16 oz (350–500 mL) soon after waking up.
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Drink 8–12 oz (250–350 mL) mid-morning.
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Drink 12–16 oz (350–500 mL) with lunch and early afternoon.
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Drink 12–16 oz (350–500 mL) with dinner.
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Drink 8–12 oz (250–350 mL) in the evening if your urine is dark or you tend to wake dehydrated.
This can land you close to 2–3 liters per day without feeling like you’re chugging.
Tracking methods: urine color/volume, bottle strategy, reminders/apps
The simplest tracker is urine color. Pale yellow usually means you’re in a good range. Dark yellow often means you need more fluid.
A bottle strategy can be even easier. Pick a water bottle size you like, then decide how many refills equal your daily goal. For example, a 24 oz bottle refilled 3–4 times gets you near the target range.
Reminders help too, especially if your job keeps you moving. A timer, a watch alert, or a phone reminder can be enough. The goal is not perfect data—it’s building a habit you can keep when life is busy.
Travel/work barriers: how to hit targets without overthinking
Travel days are a common time for dehydration. You may avoid drinking because you don’t want bathroom stops, or you’re stuck in meetings. If you’re prone to kidney stones, those “low-water days” can add up.
A simple approach is to front-load part of your intake before the day gets chaotic, then sip steadily. If bathroom access is limited, small frequent sips often work better than big drinks.
Printable idea: 7-day hydration checklist + refill tracker (copy/paste)
If you like checklists, copy this into a note app:
7-Day Hydration Tracker
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Goal today: ____ oz (or ____ L)
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Bottle size: ____ oz
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Refills needed: ____ Day 1: ☐1 ☐2 ☐3 ☐4 ☐5 Day 2: ☐1 ☐2 ☐3 ☐4 ☐5 Day 3: ☐1 ☐2 ☐3 ☐4 ☐5 Day 4: ☐1 ☐2 ☐3 ☐4 ☐5 Day 5: ☐1 ☐2 ☐3 ☐4 ☐5 Day 6: ☐1 ☐2 ☐3 ☐4 ☐5 Day 7: ☐1 ☐2 ☐3 ☐4 ☐5
Add a quick note: “Urine mostly pale yellow today? Yes/No.”
If you’ve had stones before: recurrence-focused protocol
A first stone is painful. A second one can feel unfair. The tricky part is that recurrence is common if nothing changes.
Why recurrence is common
Many people who form one stone have the same underlying urine chemistry day after day—low urine volume, high urine calcium, low citrate, high oxalate, or acidic urine. Without changing the environment, the crystals can return.
This is why drinking more is not just a “nice idea.” For many prior stone formers, it’s the foundation that makes other treatments work better.
Targets for prior stone formers (higher consistency, urine output focus)
If you have a history of kidney stones, focus on the result you can see: urine volume and urine color. Many clinicians aim for at least 2 liters of urine per day, and some people need more.
Try not to “miss” hydration two days in a row. People often do fine on weekdays, then fall off on weekends, road trips, or long work shifts. Those are the days to plan for.
Coordinating with clinicians: 24-hour urine testing & tailoring by stone composition
If you’ve had more than one stone, ask about stone analysis (what it’s made of) and a 24-hour urine test. That test measures things like urine volume, calcium, oxalate, citrate, uric acid, sodium, and pH.
Why does this matter? Because “drink more water” helps almost everyone, but other steps depend on what your numbers show. For example, if urine sodium is high, reducing salt can lower urine calcium in many people. If citrate is low, citrus or medication may help. If urine is very acidic and you form uric acid stones, raising pH can be key.
Can drinking more water stop kidney stones from coming back?
Often yes. In randomized trials of people who already formed stones, higher fluid intake lowered recurrence risk (about RR 0.45) and delayed recurrence (HR 0.40). The best results come from steady daily hydration that keeps urine light yellow and urine output high.
Key takeaways (actionable summary + next steps)
Hydration works because it changes the urine environment that stones need to form. If you only do one thing to lower your risk of forming stones, make it steady daily drinking.
The 3 most important actions
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Aim for 2–3 liters per day (68–101 oz), adjusted up for heat and sweat.
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Spread fluids across the day so urine doesn’t stay concentrated for long stretches.
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Monitor results with urine color (aim for pale yellow) and consider a 24-hour urine test if you’ve had stones.
Quick-reference recap box
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Daily target: 2–3 L/day (about 8–12 cups or 68–101 oz)
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More on hot or sweaty days
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Add citrus like lemon juice if it helps you drink more (avoid lots of sugar)
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Limit cola, high-sugar drinks, and high-sodium habits
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If stones recur: get stone analysis + 24-hour urine testing
FAQs
1. Will kidney stones go away by drinking water?
Sometimes yes, sometimes no. Drinking plenty of water can help small kidney stones pass by increasing urine flow and gently flushing them through the urinary tract. This is one reason doctors often recommend hydration first, since can drinking water prevent kidney stones from growing larger and help tiny ones move out naturally. However, water usually does not dissolve most stones once they’ve formed, especially calcium oxalate stones, which are the most common type. Uric acid stones are different—they may shrink or dissolve if urine becomes less acidic, usually with medical guidance plus high fluid intake. If pain is severe, or you have fever, nausea, or vomiting, water alone isn’t enough and medical care is needed.
2. How do you stop kidney stones from forming?
The biggest step is changing what’s happening in your urine. Drinking enough water to produce a steady flow of pale yellow urine helps dilute minerals that form stones. This is why how much water to drink to avoid kidney stones is such a common question—the answer depends on achieving adequate urine volume rather than hitting an exact number. Beyond fluids, small diet habits matter: go easy on salt, limit sugary drinks, and don’t cut calcium completely—getting normal calcium from food with meals actually helps reduce oxalate absorption. Some people benefit from citrate, found naturally in citrus fruits, which can make stones less likely to form. If stones keep coming back, urine testing can help tailor prevention to your specific risk factors.
3. Can lack of water cause kidney stones?
Yes, and it’s one of the most common reasons stones form. When you don’t drink enough, your urine becomes concentrated, meaning minerals like calcium, oxalate, or uric acid are more likely to crystallize. Over time, those crystals can grow into stones. This is why doctors emphasize hydration when discussing whether can drinking water prevent kidney stones—adequate fluid intake lowers risk across all stone types. Many people don’t realize they’re under-hydrated because thirst isn’t always obvious. A simple clue is urine color—dark yellow urine often means you’re not drinking enough. Regularly spacing fluids throughout the day matters more than drinking a lot all at once.
4. Is reverse osmosis water bad for your kidneys?
For most healthy people, no. Reverse osmosis water is safe to drink and does not damage the kidneys. It contains fewer minerals than some other waters, but that doesn’t increase kidney stone risk on its own. Questions like can hard water cause kidney stones or whether mineral content matters come up often, but research shows hydration level matters far more than water hardness. What counts most is how much fluid you drink overall and how much urine you produce each day. If you’re meeting your hydration needs, the type of water usually isn’t a major factor in stone prevention.
5. What is the most common cause of kidney stones?
The most common underlying cause is concentrated urine, usually from not drinking enough fluids. When urine volume is low, stone-forming substances become more concentrated and more likely to stick together. This risk exists regardless of whether you drink tap water, filtered water, or sparkling water—questions like does seltzer water cause kidney stones often miss the bigger issue, which is total fluid intake. Diet, genetics, and certain medical conditions can increase risk, but low fluid intake is the most consistent and preventable trigger across all stone types.
6. How many ounces of water a day to prevent kidney stones?
A good starting point is about 80–100 ounces per day (roughly 2.5–3 liters), but the real goal is urine output, not a fixed number. When people ask how much water to drink to avoid kidney stones, the practical answer is to urinate regularly and see pale yellow or almost clear urine most of the day. If you sweat a lot, exercise heavily, or live in a hot climate, you’ll need more. Spreading fluids evenly throughout the day works better than drinking large amounts all at once, especially for people with a history of kidney stones.
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