In 99% of all bedwetting cases, the root cause is an inherited deep-sleep disorder. The brain sleeps so deeply that it fails to respond to the signals from the bladder hence the bladder empties involuntarily. A small bladder capacity a weak and insensitive sphincter muscle (The sphincter muscle is the muscle that holds the urine inside the bladder) may also contribute to the problem.

During the first two to three years of life, bedwetting at night is normal and expected. Enuresis can be related to toilet training that occurred too early or was too demanding on the child. Some parents maybe very critical putting too much pressure on the child.

At the age of 5 about 7% of boys and 3% of girls have bedwetting problems. The percentages decrease rapidly after that. Enuresis may also be hereditary.

Some children do not wake up when their bladder is full or produce more urine during sleep than others. Some children have a tendency to produce more urine during their sleep than others and are unable to wakeup once their bladder becomes full.

In some children, their bladders do not hold as much urine as other children's do.

Physical causes are rare, but may include lower spinal cord lesions, congenital malformations of the genitourinary tract, infections of the urinary tract or diabetes.

Sometimes bedwetting is associated with sleep problems such as sleepwalking and nightmares.

A psychologically stressful event in the childs life is often found to cause bedwetting.

Food allergies, have been found by researchers to also be a cause for bedwetting in children.