Housesoiling is a common behavior that can be extremely frustrating for pet owners. Many things can lead to this situation introducing new pets or people (especially babies), changes in daily routine, inadequate litterbox hygiene and changes in litter type or box location. Breeding status or season, urinary tract infections and other medical problems particularly those that cause bladder irritation or excessive urine production can also contribute.
Some cats will change behaviors based on subtle changes in routine, degree of owner interaction or the owner's emotional state. Cats are sensitive creatures and may respond to things in the household that people would never notice. But medical problems may be the cause, so new elimination problems should be pursued initially with a veterinary checkup and urinalysis. In certain situations, your doctor may also recommend a blood panel and fecal exam. These are essential steps when drugs may be used to treat the problem at hand, as drugs may exacerbate or mask an underlying disease. Altering, especially male cats, may be vital in curbing spraying or inappropriate urination.
Cleaning carpets is an important step in controlling inappropriate elimination behavior, but replacing carpet early on generally is not recommended. Fix the problem first if possible, then purchase new carpet and padding, with thorough under-the-carpet decontamination.