Q. I have a 1-year-old German Shepherd Dog mix, and her urination is very frequent. I stop giving her water around 7 p.m., but she still needs to go outside about every 15 minutes — even around 9:30 p.m. She appears to be heathy and does not seem to be in any pain when she goes. Is this normal? 
A. Being an emergency vet is a lot like being a homicide detective. Every patient has a problem, but they can't talk, and you have to figure out what's going on.
Since your dog is young, but not considered a puppy, urinating every 15 minutes or so would not be considered normal. Because she is a female and relatively young, I would be suspicious of a urinary tract infection. Females are more susceptible to urinary tract infections because of their anatomy. Just like humans, females have a short urethra (the tube that empties the bladder), and it is relatively easy for bacteria to get inside it.
Your young dog also has a relatively unchallenged immune system, so she may not be able to fight off infections as well as an adult who has probably seen certain bacteria several times before and developed some immunity to it. Bladder infections are very irritating to the bladder wall, causing the urge to urinate small amounts frequently.
But like a good detective, you have to keep an open mind. This could also be a bladder irritation from bladder stones, which can form when certain minerals in the urine form into solid objects when the pH of the urine is especially high or low.
In an older dog, you might be suspicious of a hormonal imbalance that affects the kidneys' ability to concentrate urine, causing frequent urination. This is a very serious condition that can lead to severe dehydration if it progresses.
Some dogs have a condition called psychogenic polydypsia, which causes obsessive water drinking, followed by excessive urination. Not surprisingly, these dogs may have neurotic owners or come from an unusual household. Actually, Raindog, who is my 1-year-old Lab cross, is somewhat goofy this way, drinking bowl after bowl of water for no reason other than her love for the pastime.
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