After 10 years in business on Power Inn Road in Sacramento, Animal Den Pet Resort & Spa is undergoing a significant expansion to accommodate a long waiting list of vacation boarders and day-care clients.

Owner Lisa Chafee told me that she’s invested close to $1 million to renovate a 17,000-square-foot property next door to the original Animal Den location. The current facility, which has 24,000 square feet, will remain open for day-care clients, while the new site will house dogs while their owners are away on vacation.

“I have ... dogs that have been on the waiting list for day care for a year, trying to get into our program,” Chafee said. “People ... are calling every week and asking, ‘Is it done yet?’ ”

The new facility will open quietly later this week, Chafee said, but the public and their pooches are invited to a grand opening celebration from 11 a.m. to 3 p.m. Oct. 24. Chafee has arranged for a photo booth, food trucks and pet adoptions that day.

Her new facility features two large play yards, an area with a 30-by-40-foot wading pool with shooting water features, plus self-draining canine turf. Boarding dogs can opt to play indoors or outdoors, Chafee said, and an employee monitors outdoor play at all times. There are separate rooms for large dogs and small dogs, Chafee said, but the staff also considers the age and temperament when deciding where to place dogs.

“The pool has beach-style entry all the way around, so the dogs can get out safely from any angle,” Chafee said. “At the center, it’s 2.5 feet deep. Dogs will be escorted by staff members into the pool area, so they won’t get free range all day. There’s a rotation.”

Animal Den has a database of 6,500 clients, slightly double the number it had when Chafee acquired the business in 2006. She’s leasing the space for her new addition, she said, but she has first right of refusal if the current owners decide to sell.

The 46-year-old Chafee worked eight years as a registered dietitian in Los Angeles before she entered the doggie day-care business. She has a bachelor’s degree in nutrition and a master’s in chemistry, both from California Polytechnic State University, San Luis Obispo.

Friends would ask her to pet-sit for them when they went out of town, and Chafee found that she liked that work a lot better than being a dietitian. Through referrals, she said, her list of clients kept growing.

One morning in 2000, she made a call to her mother, Sheila Davison, and told her, “I’m going to quit my job and open a dog day-care business.”

Her mom said, “You’re going to do what? Why did I put you through school?”

Chafee responded: “No, trust me, I can make a lot more money, and I’m happier. I don’t have any headaches. This is totally for me.”

Chafee said Davison then told her to run with the idea, and she did. In 2005, she said, she wanted to be close to her family, so she sold her Los Angeles business and moved to the Sacramento region.

At home, Chafee and her husband of nearly three years, Eric Aylor, have six canine companions: Australian shepherds Fred, Huck and Silky; the lone husky, Timber; and Labrador retrievers Kole and Bosli.

These days, Chafee said, Animal Den houses a handful of cats and 80-plus dogs each day. She isn’t completely done with expanding her business. She acquired a parcel right behind Animal Den and plans to add a pool there for her day-care dogs. Right now, she said, they’re using kiddie pools at her day-care facility.