A cat's urinary system never stops working. Normally, a cat will need to urinate several times a day. Food and liquid the cat eats are first taken to the digestive system, but then the waste materials are filtered by the nephrons, the basic working units in the cat's kidneys. After the nephrons have filtered the waste material, it is sent to the ureter, which is a tube that connects to the bladder. The tube that connects the bladder to the genital openings is the urethra. Normally, there aren't any obstructions to stop this continual process.
According to "ASPCA Complete Guide to Cats," if the urinary tract is blocked, the cat will only live from 48 to 72 hours. In cats, urinary tract blockage happens to males more often than females, due to the smaller opening in which to pass urine. Blockage can be from a formation of crystalline-like minerals or thick mucus. These can happen from cystitis, urethritis or idiopathic feline lower urinary tract disease (FLUTD). Symptoms of all three conditions are the same, but in FLUTD the symptoms will be more pronounced. The cat will cry out when urinating, pass blood when urinating, miss the litter box, only be able to dribble urine and constantly lick the genital area. If the cat does not get immediate treatment, it could go into a coma and die.
Cats have been known to survive long voyages without food or water for up to one month. One such cat was Emily, who survived a trip in a shipment container from Wisconsin to France. When discovered, she was thirsty, but still alive. Cats do urinate during this time, but it is unknown how long they can go without urinating when they are not taking in food and water. The need for urination is less because there just isn't any food that needs filtering.