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Cloudy Urine: What It Means, Common Causes and How to Read a Cloudy Urinalysis

Cloudy urine is often harmless, from phosphate crystals in alkaline urine or a sample that stood too long, but it can also be a sign of a urinary tract infection. Learn the common causes in women and men, how to read "Appearance: cloudy" next to the other lines on a urinalysis, and what to do next.

Published

November 2, 2026

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13 min read

Medically reviewed by

Rhonda Collins, FNP-C

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Cloudy urine is often harmless, but it can be a sign of a urinary tract infection (UTI). A common harmless cause is phosphate crystals coming out of solution in alkaline urine. The main cause that needs attention is infection, where white blood cells (pus) and bacteria cloud the urine ^[1][2][3].

What decides which one you have is not the cloudiness itself. It is whether you have symptoms, and what the rest of a urinalysis shows. In a review of office urinalysis, a cloudy appearance raised the odds of a UTI about threefold (a positive likelihood ratio of 3), which is useful but far from a diagnosis ^[2]. Nitrite, leukocyte esterase, white blood cells and bacteria on the same report carry much more weight ^[2].

What makes urine cloudy

Urine turns cloudy when something is suspended in it that scatters light. MedlinePlus lists bacteria, crystals, fat, white or red blood cells, and mucus as possible causes of milky urine ^[1]. Reviews of urinalysis add phosphates, oxalates, lymph fluid (chyle) and lipids ^[2][3].

A lab records this as appearance, or clarity, during the physical part of a urinalysis: it notes whether the sample is clear or cloudy to the naked eye ^[4]. The microscopic part then looks for the cells, crystals and other particles that explain it ^[4]. For the reference page on this line, see urine clarity. For changes in color rather than clarity, see urine color.

Harmless causes of cloudy urine

Cloudy urine is often the result of phosphate crystals precipitating in alkaline urine ^[3]. Several other causes have nothing to do with the bladder or kidneys at all.

• Phosphates in alkaline urine. Urine is normally slightly acidic. When it is alkaline, phosphate can come out of solution as fine crystals or amorphous sediment and make the sample look cloudy ^[2][3]. A diet high in citrate can make urine alkaline ^[2][3].
• A sample that stood or cooled. Crystals can form in normal urine as it cools, so only fresh samples should be examined for crystals ^[2]. Delays of more than two hours between collection and examination often give unreliable results, which is why samples that cannot be tested promptly are refrigerated ^[3].
• Contamination during collection. Skin cells and bacteria from the genital area can end up in a sample that was not collected midstream ^[5]. Many squamous epithelial cells on the report are the sign of this ^[2][3].
• Vaginal discharge. Normal discharge can be cloudy or white, and it increases around ovulation, in pregnancy and with sexual arousal ^[6]. Discharge picked up during collection can cloud a sample.
• Semen in the bladder. Cloudy urine after orgasm is the main sign of retrograde ejaculation, covered below. A urinalysis taken soon after ejaculation then shows a large amount of sperm ^[7].
• Purine-rich foods. Reviews of urinalysis list a diet high in purine-rich foods, through extra uric acid in the urine, as one cause of cloudy or white urine ^[2][3].

What about dehydration? The sources reviewed for this article list severe dehydration as a cause of dark urine, not cloudy urine ^[1]. If cloudiness keeps coming back, or comes with symptoms, a fresh urinalysis shows the cause.

Cloudy urine and infection

A urinary tract infection is the cause of cloudy urine that most often needs treatment. MedlinePlus calls cloudy or milky urine a sign of a UTI, which may also cause a bad smell ^[1]. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) lists cloudy, bloody or strong-smelling urine among the symptoms of a bladder infection ^[8].

Other bladder infection symptoms include ^[8][9]:

• burning when you urinate;
• frequent or intense urges to urinate, even when little comes out;
• pain, pressure or cramping in the lower abdomen.

In an infection, the cloudiness comes from white blood cells and bacteria in the urine ^[1][3]. That is why the infection lines on a urinalysis, not the appearance line, decide whether an infection is likely. See what nitrites in urine mean for how nitrite and leukocyte esterase are read together.

Cloudy urine without symptoms is a different situation. Bacteria in the urine with no urinary symptoms is called asymptomatic bacteriuria ^[10]. The Infectious Diseases Society of America (IDSA) recommends screening for and treating it only in pregnancy and before invasive urologic procedures, and not in healthy women, older adults or people with diabetes ^[11]. Without symptoms, a urine culture is useful only in those two situations ^[2].

Sexually transmitted infections and vaginal causes

Sexually transmitted infections (STIs) can put white blood cells and discharge into urine, which can make it look cloudy. Gonorrhea and chlamydia can cause discharge from the penis or an abnormal or increased vaginal discharge, along with burning when you urinate ^[12][13]. Trichomoniasis can cause penile discharge, or a thin, white, yellowish or greenish vaginal discharge with a fishy smell ^[14].

Many people with gonorrhea or chlamydia have no symptoms at all ^[12][13]. On a urinalysis, an STI can show up as positive leukocyte esterase and white blood cells with a negative culture ^[2][3]. A standard urinalysis does not test for STIs. A first-morning urine sample collected without cleansing detects STIs better than the midstream clean-catch sample used for a UTI ^[2], so STI testing is a separate test.

Vaginal infections that are not sexually transmitted, such as a yeast infection or bacterial vaginosis, also change discharge ^[6]. If the change is in your discharge rather than your urine, that points away from the bladder.

Cloudy urine and kidney stones

Kidney stones can cause cloudy or bad-smelling urine. NIDDK lists it among stone symptoms, along with ^[15]:

• sharp pain in the back, side, lower abdomen or groin;
• pink, red or brown blood in the urine;
• a constant need to urinate, or pain when urinating;
• being unable to urinate, or passing only a small amount.

NIDDK also lists nausea, vomiting, fever and chills, and advises seeing a clinician right away for any of these symptoms ^[15]. On a urinalysis, white blood cells with severe pain, red blood cells and crystals together suggest a stone ^[2]. Crystals alone can be seen in healthy people and do not mean you have a stone ^[3]. For blood on the same report, see what blood in urine test results mean.

Cloudy urine, diabetes and kidney disease

Cloudy urine is not a sign of diabetes or kidney failure on its own. The connection runs through other causes.

Diabetes. Diabetes raises the risk of UTIs ^[9], and it is one cause of retrograde ejaculation ^[7]. Both can make urine cloudy. On a urinalysis, it is glucose on the dipstick, not cloudiness, that often points to uncontrolled diabetes ^[2][4]. Blood tests confirm it.

Kidney disease. NIDDK says most people with early chronic kidney disease have no symptoms, and many have none until the disease is advanced ^[16]. The urine change it lists for advanced disease is foamy urine, not cloudy urine ^[16]. For many people, blood and urine tests are the only way to find kidney disease ^[16]. For persistent bubbles, see what foamy urine can mean.

The kidney problem that does cause cloudy urine is a kidney infection. A bladder infection can spread to the kidneys, and that and adds fever, chills and pain in the back, side or groin ^[8][9].

Cloudy urine during pregnancy

In pregnancy, cloudy urine should go to your prenatal clinician, even without symptoms. Pregnancy raises the risk of UTIs ^[9], and it is one of the two situations where IDSA recommends screening for and treating bacteria in the urine even when you feel well ^[11]. A urine culture is the test used for that screening ^[10].

Pregnancy also increases normal vaginal discharge ^[6], which can cloud a sample. A careful clean-catch collection helps keep it out ^[5]. Pregnant people with a UTI who have a fever or feel ill may need hospital care ^[9].

Cloudy urine in men

In men, cloudy urine is less likely to come from contamination, so infection and a few male-specific causes matter more. The presence of bacteria in a properly collected male sample suggests infection, and a culture should be obtained ^[3].

• Retrograde ejaculation. Semen goes backward into the bladder during orgasm instead of out of the penis. Its main signs are cloudy urine after orgasm and little or no semen ^[7]. Causes include diabetes, some blood pressure and mood medicines, and prostate or urethra surgery or medicines ^[7]. It is usually not a problem unless you are trying to conceive ^[7]. The foamy urine article covers how it differs from foam.
• Prostatitis. Bacterial prostatitis can cause a UTI, with bacteria and white blood cells in the urine ^[17]. Acute bacterial prostatitis comes on suddenly with fever, chills, burning, and pain in the genital area, groin, lower abdomen or lower back, and NIDDK advises immediate medical care ^[17].
• STIs. Gonorrhea, chlamydia and trichomoniasis can cause a discharge from the penis ^[12][13][14].

Cloudy urine in women

In women, cloudy urine most often comes from a UTI, vaginal discharge or a contaminated sample. Women get UTIs more often than men because the urethra is shorter and closer to the anus. Sexual activity, a diaphragm and menopause all increase the risk ^[9].

Vaginal discharge is the other common source. It can be clear, cloudy or white, and its amount rises around ovulation and in pregnancy ^[6]. In a clean-catch sample from a woman, vaginal flora contamination is frequent ^[3]. Many squamous epithelial cells on the report point to it ^[2]. A careful midstream repeat usually settles the question ^[5].

”Cloudy” on a urinalysis: the lines that explain it

On a urinalysis report, “Appearance: cloudy” or “turbid” is a description, not a diagnosis. It means the sample was not clear. The other lines on the same report tell you why. On a Mito report, appearance and the lines below can be read side by side.

Some common patterns:

• Cloudy, with positive nitrite, leukocyte esterase, white blood cells and bacteria. This pattern, with symptoms, fits a UTI. A culture identifies the bacteria ^[2].
• Cloudy, with amorphous sediment or phosphate crystals, alkaline pH and negative infection lines. This pattern fits harmless phosphate precipitation ^[2][3].
• Cloudy, with many squamous epithelial cells and some bacteria. This pattern suggests contamination. A fresh clean-catch repeat is the next step ^[2].
• Cloudy, with white blood cells and leukocyte esterase but a negative culture. This pattern can come from an STI, a stone or other inflammation ^[2][3].

What to do after cloudy urine or a cloudy urinalysis

1. Note your symptoms. Burning, urgency, a strong smell, pelvic or back pain, fever, discharge, or cloudiness only after orgasm each point toward a different cause ^[8][15][7].
2. Read the other lines on the report. The table above shows which lines point to infection and which point to crystals or contamination.
3. Repeat a fresh clean-catch sample when the result is unclear. Wash your hands and clean the genital area, start urinating into the toilet, then collect the middle of the stream ^[5]. If possible, collect when urine has been in your bladder for 2 to 3 hours ^[5]. Get the sample to the lab promptly, or refrigerate it until you can ^[3][5].
4. Get a urinalysis with microscopy. The microscopic exam is what separates crystals from white blood cells and bacteria ^[4].
5. Get a urine culture when an infection is suspected. A culture is recommended when UTI symptoms are present ^[2]. It shows which bacteria, if any, are growing, and results take 24 to 48 hours ^[18]. A routine urine culture can be ordered on its own.
6. See a clinician if cloudiness keeps coming back on fresh samples, or if any of the prompt-care signs below apply.

The Urinalysis, Complete Test with Reflex to Urine Culture reports appearance together with each line in the table above, itemized: white blood cells, bacteria, squamous epithelial cells, crystal types, amorphous sediment and pH. If the urinalysis shows signs of a possible infection, a urine culture runs automatically. The Urinalysis, Routine Test reports appearance and the dipstick lines, including nitrite, leukocyte esterase and pH. How much microscopy detail it itemizes depends on the lab that runs it.

When to get prompt care

Contact a clinician if cloudy urine comes with symptoms of a UTI ^[8][9]. Seek care right away for signs that an infection may have reached the kidneys, or for stone symptoms ^[8][15]:

• fever or chills;
• pain in the back, side or groin;
• nausea or vomiting;
• blood in the urine;
• being unable to urinate.

If you are pregnant, contact your prenatal clinician about cloudy urine or urinary symptoms, and seek care promptly for a fever or feeling ill ^[9][11].

References

1. MedlinePlus. Urine - abnormal color. National Library of Medicine. Reviewed July 1, 2025.
2. Hitzeman N, Greer D, Carpio E. Office-based urinalysis: a comprehensive review. Am Fam Physician. 2022;106(1):27-35B.
3. Simerville JA, Maxted WC, Pahira JJ. Urinalysis: a comprehensive review. Am Fam Physician. 2005;71(6):1153-1162.
4. MedlinePlus. Urinalysis. National Library of Medicine. Reviewed January 1, 2025.
5. MedlinePlus. Clean catch urine sample. National Library of Medicine. Reviewed July 23, 2024.
6. MedlinePlus. Vaginal itching and discharge: adult and adolescent. National Library of Medicine. Reviewed August 18, 2025.
7. MedlinePlus. Retrograde ejaculation. National Library of Medicine. Reviewed January 1, 2025.
8. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms and causes of bladder infection in adults. Last reviewed April 2024.
9. MedlinePlus. Urinary tract infection: adults. National Library of Medicine. Reviewed July 23, 2024.
10. MedlinePlus. Asymptomatic bacteriuria. National Library of Medicine. Reviewed July 23, 2024.
11. Nicolle LE, Gupta K, Bradley SF, et al. Clinical practice guideline for the management of asymptomatic bacteriuria: 2019 update by the Infectious Diseases Society of America. Clin Infect Dis. 2019;68(10):e83-e110. PMID: 30895288
12. Centers for Disease Control and Prevention. About gonorrhea. January 31, 2025.
13. Centers for Disease Control and Prevention. About chlamydia. January 31, 2025.
14. Centers for Disease Control and Prevention. About trichomoniasis. January 31, 2025.
15. National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms and causes of kidney stones. Last reviewed May 2017.
16. National Institute of Diabetes and Digestive and Kidney Diseases. What is chronic kidney disease? Last reviewed February 2025.
17. National Institute of Diabetes and Digestive and Kidney Diseases. Prostatitis: inflammation of the prostate. Last reviewed July 2014.
18. MedlinePlus. Urine culture. National Library of Medicine. Reviewed October 9, 2024.

Frequently asked questions

Is cloudy urine normal?

It can be. A common harmless cause is phosphate crystals that come out of solution in alkaline urine, and crystals can also form in a normal sample as it cools. Cloudy urine can also be a sign of a urinary tract infection, especially with burning, urgency or a strong smell. Cloudiness that keeps coming back, or comes with symptoms, is worth a urinalysis.

Does cloudy pee mean kidney failure?

Not on its own. The National Institute of Diabetes and Digestive and Kidney Diseases says most people with early chronic kidney disease have no symptoms, and the urine change it lists for advanced disease is foamy urine, not cloudy urine. Blood and urine tests are how kidney disease is found. Cloudy urine with fever, chills and back or side pain can be a sign of a kidney infection, which needs prompt care.

Does cloudy pee mean diabetes?

Cloudy urine is not a test for diabetes. Diabetes is linked to it indirectly: it raises the risk of urinary tract infections and is one cause of retrograde ejaculation, and both can make urine cloudy. On a urinalysis, the glucose line, not the appearance line, is the one that can suggest uncontrolled diabetes, and blood tests confirm it.

What foods cause cloudy urine?

Reviews of urinalysis list a diet high in purine-rich foods as one cause of cloudy or white urine, through extra uric acid in the urine. Diets high in citrate can make urine alkaline, and phosphate crystals tend to come out of solution in alkaline urine. Cloudiness from food is harmless, but it is a diagnosis to reach only after infection signs are ruled out.

How do you flush out cloudy urine?

There is no single flush, because the right step depends on the cause. Cloudiness from phosphate crystals is harmless and needs no treatment. When cloudy urine comes from a bladder infection, MedlinePlus advises drinking plenty of water, but the infection itself usually needs to be diagnosed and treated by a clinician. If cloudiness keeps coming back, a fresh clean-catch urinalysis shows which cause applies.