A kidney stone that reaches the bladder can stay there indefinitely if your bladder can’t fully empty. Small stones (under 1 cm) may pass on their own within days to weeks, but there’s no guaranteed timeline. Stones that form in or migrate to the bladder often grow larger the longer they remain, making spontaneous passage less likely over time.
Why Some Stones Pass and Others Don’t
Once a kidney stone drops into the bladder, it has already survived the hardest part of its journey. The urethra, the tube that carries urine out of your body, is the final stretch. For a small stone in someone with normal bladder function, the stone can wash out during urination within hours to a few days. Drinking extra water can help move it along.
The problem is that many people who develop bladder stones have an underlying issue that prevents the bladder from emptying completely. An enlarged prostate is one of the most common culprits in men. Nerve damage affecting the bladder, prior surgeries, or chronic catheter use can also trap urine and stones inside. When residual urine sits in the bladder, minerals continue to crystallize around the stone, and it grows. A stone that was small enough to pass last week may not be small enough next month.
European urology guidelines note that stones under 1 cm are likely to pass on their own, but only when there’s no bladder obstruction or dysfunction present. If you do have one of those conditions, even a small stone can remain in the bladder for months or years, steadily getting larger.
How You Know a Stone Is Still There
Small bladder stones sometimes cause no symptoms at all, which is one reason they can linger undetected. As a stone grows or shifts position, you’ll typically notice some combination of the following:
- Interrupted urine stream. The stone can roll over the bladder’s opening, temporarily blocking flow. You may start and stop mid-stream or feel like you can’t fully empty.
- Pain in the lower abdomen or pelvis. This often worsens with movement or exercise.
- Blood in the urine. The stone irritates the bladder wall, causing visible pink, red, or brown urine.
- Frequent or painful urination. Bladder stones commonly trigger urinary tract infections, which bring burning, urgency, and cloudy or foul-smelling urine.
These symptoms can come and go depending on where the stone sits inside the bladder at any given moment. A stone resting quietly at the bottom of the bladder might cause nothing, then shift during a run and block urine flow for a few seconds.
What Happens If You Leave It
Waiting too long carries real risks. Bladder stones that don’t pass on their own can lead to chronic urinary problems, including persistent pain and the need to urinate far more often than normal. Repeated urinary tract infections are common because bacteria cling to the stone’s surface and reinfect the bladder even after a round of antibiotics clears the original infection.
A growing stone can also become lodged in the opening where the bladder meets the urethra, completely blocking urine flow. That’s a medical emergency. Over time, the stone’s constant contact with the bladder wall can cause thickening and irritation that outlasts the stone itself. The longer a stone stays, the larger it gets, and the more complicated removal becomes.
When Stones Need to Be Removed
Most bladder stones require removal. Drinking extra water is worth trying for a small, recently arrived stone in someone whose bladder empties well, but it often isn’t enough. As the Mayo Clinic puts it plainly: because bladder stones are usually caused by incomplete emptying, extra water alone might not solve the problem.
The standard removal procedure is minimally invasive. A thin scope is passed through the urethra into the bladder, and the stone is broken apart with laser or ultrasound energy, then flushed out. Recovery is typically quick, often just a day or two of mild discomfort. Stones that have grown too large or too hard to break up this way require a small surgical incision instead.
Critically, removing the stone is only half the solution. If the underlying cause, like an enlarged prostate or nerve condition, isn’t addressed, new stones will form in the same spot. Your doctor will usually investigate why the stone was there in the first place and recommend treatment for that root issue to prevent recurrence.
Practical Timeline to Keep in Mind
If you’ve been told a kidney stone has entered your bladder and you have normal bladder function, give it a few days to a week while staying well hydrated. If it hasn’t passed by then, or if symptoms worsen, imaging can confirm whether the stone is still present and how large it is. For stones that arrived in the bladder alongside known emptying problems, waiting rarely helps. The stone will almost certainly need to be removed, and sooner is better than later since every extra week gives it time to grow.