Me against the cat pee.

"The cats were fine," said our house sitter cheerily upon our arrival home from a two-week vacation. "Oh, I think you should smell something in the basement."

I didn't want to smell something in the basement. I wanted to pick up my suitcase, go out to the sidewalk, hitch a ride to the train station, and start over as a hobo. I knew the life of a hobo would smell better than what awaited me in the basement. Instead, my husband, daughter, and I trooped down the stairs. Our eyes teared as the ammonia hit us. We followed our noses to a corner of the room. I bent down and touched the rug. It was dank and saturated with cat urine.

We were used to our house smelling like a biological weapons lab. About a year after getting our cats, Goldie and Biscuit, we decided to become dog owners and adopted a stray beagle, Sasha. It had taken us about nine long months to get Sasha housebroken. But for the past six months, the cats and dog had been doing their duty where they were supposed to. The condition of the basement couldn't be because Sasha was regressing; we'd farmed her out to her trainer while we were gone.

I knew that cats often get angry when owners leave, so I hoped that as home-life returned to normal, so would the cats. I called the carpet-cleaning company and asked for the Love Canal-strength deodorizers. The receptionist told me no one could guarantee complete removal of cat urine scent. She started laughing as she told me about one customer who had to not only pull up his basement carpet, but take a jackhammer to the fouled concrete below. I was lucky. The cleaning, and an arrangement of window screens blocking the corner, solved the basement problem.

But over the next few weeks it was clear there was no more normal. In the morning I would find the mat in the kitchen soaked, the den carpet soggy, my bathmat sopping. The dog spent the night in her crate. It had to be the cats.

It was small comfort to discover that vast numbers of cat owners are, like me, walking around with wet socks. "Inappropriate elimination" is the No. 1 cat behavior problem. Betsy Lipscomb, founder of Cats International, a volunteer organization that provides freetelephone counseling for desperate cat owners, told me that of the almost 5,000 calls she gets a year, nearly 90 percent are related to out-of-the-box soiling. It is the most common reason cats are turned in to shelters, where the likelihood is minuscule that a Persian cat who pees on the Persian carpet will find a new home. At least my situation was not as dire as that of the man who called the hotline to complain that his cat would urinate only on the stove. Whenever he cooked he turned on the burners and ran from his home until the urine burned off.

Cat litter has made possible the indoor-only cat, leading cats to surpass dogs as America's most popular pet. The modern cat-litter industry was started in 1947, when the late Edward Lowe, helping a cat-owning neighbor, suggested she use in a cat box the absorbent clay he sold for cleaning oil drips at machine shops. She was so happy with the result that he put some in bags, called it Kitty Litter, and, after convincing a skeptical pet store owner to first let him give it away, began selling it to grateful cat lovers. He became a multimillionaire, and cat litter became a $1.3 billion-a-year business.

As I read through the litter literature, I realized the deductive skills needed to analyze the causes of elimination problems could provide CBS with a new spinoff: CSI: Cat Pee. Anything from the purchase of a new piece of furniture, to the owner having a change in work schedule could cause a cat to soil in protest.

When my soiling problem first happened, I immediately took the cats to the vet, where $280 worth of urinalysis revealed they had no physical problems. The vet gave me a tip sheet for eliminating the elimination problem. Following all the vet's tips, and combining them with the other advice I read, would lead to a litter-box care program that was only slightly less consuming than embarking on a career as a professional gymnast.

I was to get all new litter boxes, three for two cats. They needed to be scooped daily, then completely emptied and washed with scalding water weekly. When I got home from the pet store I noticed that the instructions on the box of litter recommended replacing it only monthly. Even the cat litter company didn't have the nerve to try to quadruple its sales with a "dump weekly" program. (Lipscomb says a well-maintained box does not need such frequent discarding.)