Would you pay triple to live on the water?

We all know coastal living is expensive, but just how much more would it cost you to live as close to the water as possible in San Diego?

A new study by Zillow says a waterfront house in America’s Finest City costs 240 percent more than the median-priced home.

The real-estate tracker defines waterfront living as a home located within 150 feet of the waterline, separated only by a road with a speed limit of less than 25 miles per hour. Locally, most of those properties are in the Mission Bay area, and also around the San Diego Yacht Club on Shelter Island.

Zillow says the median value of a San Diego waterfront home is $1,924,500. That’s nearly 3.5 times the $564,900 median for all other single-family homes. The gap in San Diego is the second-largest in California behind Long Beach, and seventh-highest in the country.

“Waterfront properties are both relatively scarce and highly coveted, and that high demand and limited supply leads to higher home prices,” Zillow chief economist Stan Humphries said in a statement. “Additionally, added insurance, floods, environmental mitigation and infrastructure costs are often part of the tab when buying a waterfront home.”

The biggest price gap for the study was found in Tampa, Fla., where a waterfront home cost $1.04 million, or 733 percent more than a non-waterfront property’s median of $125,300. Up the California coast, Long Beach ranked third, with a 321 percent difference between a waterfront home’s median of $2.31 million and a non-waterfront home’s median of $505,200.

The smallest gap was in Jacksonville, Fla., where a waterfront home cost $157,000, or 32 percent more than a non-waterfront home.

To make its initial waterfront study consistent nationwide, Zillow disqualified many properties you might consider waterfront. For instance, homes in the Bird Rock area of La Jolla abut the shoreline, but are on a cliff, so don’t count. In San Diego, 174 qualified as waterfront.

Or in Pacific Beach, where homes line the oceanfront boardwalk, the actual water is more than 150 feet away. Zillow also did not take into account the size of home, and only included cities that have at least 100 qualifying properties.

Skylar Olsen, a Zillow economist, said back in the 1990s, the difference between waterfront properties and all others was about 1.5 times the value. Nationwide, that gap has increased to about two times the value.

“You kind of get a gradient going in,” she said. “When you’re right on the water, there is much more private access, it is much more expensive.”

Jeff Olson, chief of assessment services at the San Diego County Assessor’s Office, said typically the homeowner’s property extends to the average high tide location of the Pacific Ocean. He said the county does not keep data on how many properties are on the water.

In Coronado, the only other San Diego County city to show up on Zillow’s study, the 571 waterfront homes cost a median $1,925,800, or 32 percent more than a non-waterfront home.