Cloudy urine is usually caused by something harmless, most often dehydration. When you don’t drink enough water, waste products become more concentrated in your urine, giving it a murky or milky look. But cloudiness can also signal an infection, kidney stones, or other conditions worth paying attention to, especially if it sticks around or comes with other symptoms.
Dehydration Is the Most Common Cause
Your urine is a mix of water and dissolved waste. When you’re well hydrated, waste is diluted enough that urine looks pale yellow and clear. When you haven’t had enough fluids, those waste products are packed into less water, making urine darker and often cloudy. Normal urine concentration (measured as specific gravity) falls between 1.005 and 1.030. Values above 1.030 indicate highly concentrated urine with excess waste, which is a sign of dehydration.
The fix is straightforward: drink more water. If dehydration is the only issue, your urine should clear up within a few hours of rehydrating. If it doesn’t, something else is going on.
Urinary Tract Infections
UTIs are one of the most common medical reasons for cloudy urine. When bacteria infect the bladder or urethra, your immune system sends white blood cells to fight them off. Those white blood cells, along with the bacteria themselves, end up in your urine and make it look hazy or milky. You’ll typically also notice a burning sensation when you pee, a frequent urge to go, and urine that smells unusually strong or foul.
UTIs are far more common in women because of their shorter urethra, but men get them too. If you suspect a UTI, a simple urine test can confirm it, and antibiotics typically clear the infection within a few days.
Kidney Stones and Crystals
Minerals in your urine can form tiny crystals, and when enough of them are present, your pee can look cloudy or gritty. Common types include calcium oxalate, calcium phosphate, uric acid, and struvite crystals. The acidity of your urine influences which type of crystal is more likely to form.
Small crystals often pass without you noticing, but they can also clump together into kidney stones. If a stone moves into the ureter (the tube connecting the kidney to the bladder), you’ll feel intense pain in your side or lower back, often with nausea. Cloudy or pinkish urine alongside sharp flank pain is a strong indicator of kidney stones.
Sexually Transmitted Infections
Several STIs can make urine appear cloudy. Chlamydia, gonorrhea, and vaginitis all cause discharge that mixes with urine, creating a murky appearance. With gonorrhea, you might also see a yellowish or greenish tint. These infections often come with additional symptoms like burning during urination, unusual genital discharge, or pelvic discomfort, but they can also be present with minimal symptoms, particularly chlamydia.
Diet and Other Harmless Causes
Eating large amounts of fruits and vegetables, particularly those high in phosphorus, can temporarily cloud your urine. Dairy-heavy meals can do the same. This type of cloudiness is harmless and resolves on its own as your body processes the food. Certain vitamins and supplements, especially B vitamins, can also change the appearance of your urine.
Causes That Differ by Sex
In women, vaginal discharge is a common and often overlooked reason for cloudy-looking urine. Discharge can mix with urine during urination, making it appear turbid even when the urine itself is perfectly normal. Yeast infections and bacterial vaginosis increase the amount of discharge, making this more likely. During pregnancy, preeclampsia (a dangerous condition involving high blood pressure) can cause protein to leak into the urine, giving it a foamy, cloudy appearance.
In men, prostate issues can contribute. Prostatitis, or inflammation of the prostate gland, can release prostatic fluid into the urinary tract. A less common cause is retrograde ejaculation, where semen flows backward into the bladder instead of out through the penis during orgasm. This happens when the muscle at the bladder opening doesn’t tighten properly, and the result is cloudy urine after sex. It’s not dangerous, but it can affect fertility.
Diabetes and Chronic Kidney Disease
Diabetes can cause sugar to accumulate in your urine. When blood sugar levels are consistently high, the kidneys can’t reabsorb all the glucose, and the excess spills into your pee. High sugar levels in urine give it a cloudy appearance and sometimes a slightly sweet smell. If you’re noticing cloudy urine alongside increased thirst, frequent urination, and fatigue, uncontrolled blood sugar could be the cause.
Chronic kidney disease damages the kidneys’ filtering ability over time, allowing protein, blood cells, and other substances to leak into urine. This produces cloudiness that tends to be persistent rather than coming and going. Foamy urine is a particularly telling sign of protein leakage.
Lymphatic Leakage (Chyluria)
Rarely, cloudy or milky-white urine is caused by lymphatic fluid leaking into the urinary tract, a condition called chyluria. Lymphatic fluid is normally a clear, fat-rich liquid that circulates through your immune system. When there’s an abnormal connection between the lymphatic system and the kidneys, that fatty fluid ends up in your urine, turning it a distinctive milky color.
The most common cause worldwide is a parasitic infection called lymphatic filariasis, found in tropical and subtropical regions. Non-parasitic causes include tuberculosis, certain cancers that obstruct lymphatic drainage, congenital lymphatic abnormalities, and prior surgery. Chyluria is rare in the U.S. and Europe, but worth mentioning if your urine looks genuinely milky white rather than just hazy.
What the Color and Timing Tell You
Pay attention to patterns. Cloudiness that clears up after drinking a glass or two of water points to dehydration. Cloudiness that appears consistently first thing in the morning could reflect overnight concentration or a low-grade infection. Cloudiness accompanied by pain, fever, blood, or strong odor suggests something that needs medical attention.
The color matters too. Whitish, milky urine suggests phosphate crystals, discharge, or rarely chyluria. Yellowish-cloudy urine with a foul smell points toward infection. Pinkish or brownish cloudiness could mean blood is present, which warrants prompt evaluation. If your urine has been persistently cloudy for more than a day or two despite good hydration, or if you’re experiencing any pain, fever, or other unusual symptoms alongside it, a urine test can quickly narrow down the cause.