if I buy a house and want to put a pool in, can I have the cost of the pool wrapped into the loan?

Conventional renovation loans are the ones built for this — Fannie Mae's HomeStyle Renovation and Freddie Mac's CHOICERenovation both let a buyer roll the pool cost into the same mortgage used to buy the house. The loan amount is based on the home's after-improved value (HomeStyle allows up to roughly 75% of that as-completed value), so the appraiser factors in the pool as if it's already built. You'll typically need a contractor bid up front, and the pool funds get held in escrow and released in draws as the work is completed, rather than handed over as cash.

If you're buying new construction, a construction-to-permanent loan can often bundle the pool into the build cost directly with the builder.

Outside of those programs, the more common path is: buy the house first, then finance the pool separately afterward with a HELOC, a home equity loan, a cash-out refinance, or a dedicated pool loan.

Since lender overlays and exact terms vary, it's worth having a client (or yourself) run the specifics by a loan officer before assuming a program will cover it — I'm not a lender, so treat this as the general lay of the land rather than a quote on what you'd personally qualify for.