Short of a cash windfall, saving for a down payment on a home can take years — and in some U.S. states, it may take decades.

A new analysis from ConsumerAffairs estimates how long it would take to save a 10% down payment in every state by comparing each state’s median household income with its median home price, along with median tax burdens and essential living costs.

In Iowa, it would take about 8.7 years to save enough for a 10% down payment, the fastest of any state. In California, the estimate is 25.1 years — longer than any other state. Across all 50 states, the average timeline is 14.4 years, according to the study.

These timelines rely on what the study calls “fractional saving,” which assumes a household sets aside 10% of its discretionary income each year.

That approach was chosen because “that’s how people really save,” Dayna Edens, media relations manager at ConsumerAffairs, tells CNBC Make It. “Nobody’s setting aside every spare penny for a down payment on a house they’re not even shopping for yet.”