Bladder stones form when urine sits in the bladder too long, allowing minerals to crystallize into hard deposits. The single most important thing you can do to prevent them is ensure your bladder empties completely and regularly. Beyond that, staying well-hydrated, managing underlying conditions, and watching your diet all play significant roles in keeping stones from forming.
Why Bladder Stones Form
Urinary stasis, meaning urine that stays in the bladder instead of being fully expelled, is the primary cause of bladder stones. When urine pools, dissolved minerals like calcium, uric acid, and phosphate become increasingly concentrated. Eventually they crystallize and clump together into stones that can range from grain-of-sand size to golf-ball size.
Bladder stones account for about 5% of all urinary stones and are most common in men over 50. The conditions that lead to incomplete emptying are the real culprits: an enlarged prostate (benign prostatic hyperplasia, or BPH), nerve damage affecting bladder function (neurogenic bladder), bladder outlet obstruction, and long-term catheter use. If you can address the reason your bladder isn’t emptying, you eliminate the environment stones need to grow.
Treat the Underlying Condition First
If you have an enlarged prostate, managing it aggressively is the most effective form of bladder stone prevention. BPH causes the prostate to squeeze the urethra, trapping urine in the bladder after you urinate. Medications that relax the prostate or shrink it can help, but research shows that when prostate tissue protrudes significantly into the bladder, medication alone often fails to prevent complications. In those cases, surgical intervention to open the blocked pathway is considered the standard approach, and the presence of bladder stones in someone with BPH is itself an indication for surgery.
For people with neurogenic bladder from spinal cord injuries, multiple sclerosis, or other nerve conditions, the goal is the same: get urine out of the bladder on a reliable schedule. Intermittent catheterization, where a thin tube is inserted to drain the bladder at regular intervals, is the most common strategy. Consistent timing matters more than any supplement or dietary change.
If You Use a Catheter
Long-term catheter use is a well-known risk factor for bladder stones because the catheter itself can serve as a surface for mineral deposits to build on. A few principles reduce that risk. Use the smallest catheter size that still allows good drainage. Keep urine flowing freely at all times by avoiding kinks in the tubing and keeping the collection bag below bladder level. Don’t disconnect the catheter from the drainage system unnecessarily, since each disconnection introduces infection risk.
Routine bladder irrigation with saline or antibiotic solutions was once common practice, but current guidelines recommend against it unless there’s a suspected blockage. If your catheter requires frequent flushing to stay clear, that’s a sign it needs to be replaced rather than repeatedly irrigated. Catheters should be changed on a regular schedule as recommended by your care team.
Drink Enough to Keep Urine Dilute
High fluid intake is one of the simplest and most effective prevention strategies. When you drink more, your urine becomes less concentrated, making it harder for minerals to crystallize. A Cochrane review of the evidence found that people who drank more than 2.5 liters of water per day (roughly 10 to 11 cups) had a meaningfully lower rate of stone formation compared to those drinking less than 1.2 liters.
For people who’ve already had a stone, the target is producing at least 2 liters of urine per day, which generally means drinking at least 2.5 to 3 liters of fluid. In one study, participants who hit that urine volume averaged over 2,600 mL of urine daily, compared to about 1,000 mL in the control group. Their recurrence rates dropped significantly. Water is ideal, but other fluids count too. Spreading your intake throughout the day is more effective than drinking large amounts at once, and it’s especially important to drink before bed, since urine concentrates overnight.
Prevent Urinary Tract Infections
Certain types of bladder stones, called struvite stones, form only in the presence of a urinary tract infection. Specific bacteria (most commonly Proteus, but also Klebsiella and Pseudomonas, among others) produce an enzyme called urease that breaks down urea in your urine into ammonia. This makes the urine abnormally alkaline, with a pH above 7, which creates conditions where magnesium ammonium phosphate crystals rapidly form. These stones can grow quickly and are directly tied to the infection itself.
If you get recurrent UTIs, treating and preventing those infections is essential to preventing struvite stones. Chronic or relapsing infections with the same organism are a red flag that a stone may already be present, since the stone itself harbors bacteria and reinfects the urinary tract in a cycle. In some cases, low-dose long-term antibiotics are used for chronic suppression when someone is at high risk. If a struvite stone has already formed, antibiotics alone won’t resolve it. The stone needs to be physically removed to break the infection-reinfection cycle.
Dietary Changes That Reduce Risk
What you eat affects the concentration of stone-forming minerals in your urine. The two biggest dietary levers are sodium and animal protein.
- Sodium: High sodium intake increases the amount of calcium your kidneys filter into your urine, raising the risk of calcium-based stones. The recommended limit is less than 2,300 mg per day, which is roughly one teaspoon of table salt. Most excess sodium comes from processed, canned, and fast foods rather than the salt shaker on your table.
- Animal protein: Beef, pork, chicken (especially organ meats), fish, shellfish, eggs, and dairy all increase uric acid production and make urine more acidic. This promotes both uric acid and calcium stone formation. You don’t need to eliminate these foods, but moderating portion sizes and frequency helps.
For people prone to calcium oxalate stones, eating calcium-rich foods (rather than supplements) actually helps, because dietary calcium binds to oxalate in the gut before it ever reaches the urinary tract. Cutting calcium intake, counterintuitively, can increase stone risk. Foods high in oxalate, like spinach, rhubarb, nuts, and chocolate, are worth moderating if you’ve had calcium oxalate stones before, but they’re less of a concern for first-time prevention.
Managing Urine pH for Uric Acid Stones
Uric acid stones are unique because they form in acidic urine and can actually be dissolved by making urine more alkaline. The target pH range is 6.5 to 7.0. Keeping urine in that slightly alkaline zone prevents uric acid from crystallizing while avoiding the risk of calcium phosphate stones, which form when pH climbs above 7.
Potassium citrate is the most commonly prescribed medication for this purpose. It raises urine pH and also increases citrate levels, which naturally inhibit stone crystal growth. It’s available in extended-release tablets, and your doctor adjusts the dose based on periodic urine pH testing you can do at home with pH strips. Citrus fruits and juices, particularly lemon, also contribute citrate, though not in quantities large enough to replace medication for people at high risk.
Empty Your Bladder Completely
This sounds basic, but it’s the prevention strategy that matters most. Take your time when urinating. Don’t rush. If you have trouble fully emptying, try “double voiding”: urinate, wait 30 seconds, then try again. Leaning forward slightly while sitting can help. Avoid holding your urine for long periods, as prolonged retention gives minerals more time to concentrate and crystallize.
If you consistently feel like your bladder isn’t emptying all the way, or you find yourself needing to urinate again shortly after finishing, that’s worth investigating. Residual urine volume can be measured with a quick, painless ultrasound. Identifying and correcting incomplete emptying before stones form is far easier than dealing with stones after the fact.