Q. What is it supposed to be on the show? A. A residential home. Q. Where is it supposed to be on the show? A. Somewhere in Miami. Q. When did we see it on the show? A. In Episode 4, of Season 5, "Beauty And The Beast". Quinn suspects that Dexter was somehow involved with the Trinity Killer and his wife's murder, but no one will listen to him. When artists' renderings of "Kyle Butler" resemble Dexter, Quinn wants to show Dexter's photo to Trinity's son, Jonah, to see if he can confirm Quinn's suspicion that "Kyle" and Dexter are one and the same. Unfortunately for Quinn, the FBI has Jonah hidden away in a "safe house", under the witness protection program, and they won't let Quinn near him. But Quinn won't take no for an answer. When phoning a friend at the FBI doesn't get him permission to talk to Jonah, Quinn follows that agent from a market/cafe back to the safe house. Driving past the house, Quinn spots Jonah Mitchell through the front windows. (He later approaches Jonah at a liquor store. ) Q. What is it actually in real life? A. A residential home - but not in Miami.

Q. Where can I find it in real life?

A. This house is at 3015 Stevely Avenue, in Long Beach, CA.

That's the same street where they filmed the dead skunk scene, but about 400 yards to the south, just north of Spring Street.

Like the skunk location, it's right across the street from (west of ) El Dorado Park, where they filmed the abandoned Visitors Welcome Center (where Dexter held Lumen captive), and close to the liquor store where Quinn tried to talk to Jonah.

Here is an aerial photo of the house. Here is a map link.

And here's a Google StreetView.

Q. How the heck did you figure out where it was?

A.  In previous seasons, I've usually had to hunt down the locations after viewing the episodes, using clues from the various scenes.  By the 5th season, though, I'd developed a small group of fans, spies & tipsters who kept an eye out for Dexter filming in their neighborhoods, and would let me know in advance when something was about to film there.

Between those reports, and my own personal reconnaissance around town, by the time the first episode aired, I already knew most (but not all) of the filming locations, and only needed to watch the episodes and match up the scenes with the correct locations.

This group of helpful fans includes Kerry, Rick, Joel, Geoff, Ellen, Julie, Susan, Jeff, and others. My thanks to all of them.

This particular tip came from Kerry, who also sent us the photos this season of the El Dorado Park scenes, the dead skunk scene, and the nearby liquor store.
(And last season, she got photos of the roll-over accident scene, not to mention actually landing a cameo at Trinity's arcade.
..)

Kerry, who lives near El Dorado Park, was scoping out the above park locations, when she learned that they were filming nearby, over on Stevely.  So she hurried over and shot the photos of the crew filming the skunk scene, and later shot the above photos of the safe house as well.    (Thanks, Kerry!)