When does a house size go from big to too big? That’s a question I’m sure planners have been asking themselves for several years as they’ve watched McMansions spring up and home sizes balloon.

It looks like Wellesley planners were facing that question recently. The Boston Globe reports that the Wellesley Planning Board has approved plans for a 15,000-square-foot mansion. The board has asked the owner to add 30-foot evergreen trees to maintain the privacy of abutting homes and a special rainwater collection system.

Apparently, the home size was scaled back from 16,838 square feet to address the board’s concerns. I know that property owners have rights and they should be able to do what town rules and boards allow. But really, 15,000 square feet? That sounds like more like an inn, not a home.

Wellesley has been grappling with the issue of super-sized homes for years. Hundreds of homes have been torn down in Wellesley during the last decade and a significant number of them have been replaced with multimillion dollar homes that are often thousands of square feet larger.

The town has tried to restrict home size, and this 15,000-square-foot residence that’s being planned is in a neighborhood where homes larger than 5,900 square feet are subject to a “large house review”.

But “large house” seems like a huge understatement for this proposed residence.