Symptom4 min read

Polyuria (excessive urine volume)

SpecialtyNephrologySpecialty Endocrinology and diabetesSpecialty

Detail level

Polyuria means the body makes more urine than usual each day. It is not the same as urinary frequency, which means needing to urinate more often than usual. Common causes of a larger volume include diabetes and drinking a lot of water; it deserves checking if it lasts several days without explanation.

MedlinePlus defines polyuria as producing more urine than usual, giving over 2.5 litres a day as a figure, which varies with how much water is drunk. Common causes are diabetes, diabetes insipidus and drinking a lot of water. Less common causes include kidney disease, diuretics and lithium, calcium disorders, alcohol and caffeine, sickle cell anaemia, and contrast dye. NIDDK and CDC list frequent urination among the symptoms of diabetes. Urinary frequency, by contrast, is defined by MedlinePlus as needing to urinate more often than usual; its common causes include urinary tract infection, an enlarged prostate in middle-aged and older men, and caffeine.

The assessment tests mentioned include blood sugar and electrolytes, creatinine and blood urea nitrogen, a water deprivation test, urinalysis and urine osmolality, a 24-hour urine collection, and serum osmolality (MedlinePlus). This page is about the total daily volume of urine, not the number of times a person urinates, nor painful or burning urination.

In one minute¹²³

What is it?: Producing more urine than usual over the course of the day, which is different from urinating frequently.
Who is usually affected?: It is linked to diabetes, kidney disease, certain medicines and drinking a lot of water.
Acute or chronic?: Temporary if caused by fluids, caffeine or medicines, and persistent if an illness lies behind it.
Main symptoms: Often with increased thirst, and it may be accompanied by tiredness.
Red flags?: Yes: an increase in urine volume for several days with no clear cause.
Preventable?: There is no general prevention; the underlying causes are treated.

What is it?

Increased urine volume (polyuria) means the body produces larger amounts of urine than usual each day; MedlinePlus gives over 2.5 litres a day, though this varies with the amount of water drunk.

NIDDK and CDC count it among the common symptoms of diabetes.

This differs from urinary frequency, which MedlinePlus defines as needing to urinate more often than usual. According to MedlinePlus, its common causes include urinary tract infection, an enlarged prostate in middle-aged and older men, and caffeine. If the problem is the number of times rather than the amount, discuss it with the doctor.

Possible causes

Common causes according to MedlinePlus: diabetes, diabetes insipidus, and drinking a lot of water.

Less common: kidney disease, diuretics and lithium, high or low calcium, alcohol and caffeine, sickle cell anaemia, and CT or MRI contrast dye.

How it is assessed

Tests that may be requested: blood sugar and electrolytes, creatinine and blood urea nitrogen, a water deprivation test, urinalysis and urine osmolality, a 24-hour urine collection, and serum osmolality.

When do you need urgent help?

See your doctor within days

An increase in urine volume that lasts for several days and is not explained by medicines or increased fluid intake: see a doctor.¹

Educational content only — no diagnosis, and no substitute for a clinician.

Common questions

Does increased urine volume always mean illness?

No. It may be explained by plenty of fluids, caffeine, alcohol or certain medicines. MedlinePlus advises seeing a doctor if it continues for several days without explanation.¹

What is the difference between frequent urination and increased urine volume?

Urinary frequency is needing to urinate more often than usual, whereas increased urine volume is producing a larger amount than usual in a day; MedlinePlus gives over 2.5 litres a day, which varies with how much water is drunk. Their common causes differ, so it helps to tell the doctor which of the two you notice.¹⁴

Questions for your doctor

Do I need a blood sugar and kidney test?
Could my medicines or coffee be the cause?
How do I measure my urine volume?
Do I have increased thirst or tiredness with it?

References

1
MedlinePlus. Urination - excessive amount. medlineplus.gov/ency/article/003146.htm
Health agencies & guidelines · Accessed 2026-10-06
2
NIDDK / NIH. Symptoms & Causes of Diabetes. www.niddk.nih.gov/health-information/diabetes/overview/symptoms-causes
Health agencies & guidelines · Accessed 2026-10-03
3
CDC. Symptoms of Diabetes. www.cdc.gov/diabetes/signs-symptoms/
Health agencies & guidelines · Accessed 2026-10-06
4
MedlinePlus. Frequent or urgent urination. medlineplus.gov/ency/article/003140.htm
Health agencies & guidelines · Accessed 2026-10-07

Review status: Edited content · Last updated: 2026-10-07

Change log

2026-10-06 — Page created.
2026-10-07 — Terminology corrected: the page covers increased urine volume (polyuria), distinguished from frequent urination, with common causes per MedlinePlus.