TAMPA — The Hillsborough County Property Appraiser's Office has taken to the sky to crack down on residents who build additions or install pools without proper permits.
So far, it's proving to be a revenue boost for the county.
For the past 10 months, the agency has used aerial photographs to spot changes to homes and properties made since the last appraisal was recorded. Of the 57,000 properties checked by air, more than 10,000 had their values adjusted, resulting in a net increase of $9.2 million of value to the county tax roll.
That equates to about $184,000 a year in new tax revenues. Each year the county checks one quarter of its 500,000 parcels, so that number is expected to grow as the program is expanded. (For now, Hillsborough uses aerial photos to check about half the properties it reviews each year.)
Officials hope the approach will lead to $7 million in additional tax collections over the next decade, while increasing efficiency.
"This is not a gotcha thing," said Hillsborough County Property Appraiser Bob Henriquez, who initiated the program. "There's a fairness question for folks that are doing the right thing, that are paying taxes, that have pulled permits, and meanwhile there are folks out there that put an addition on their home and should be paying."
Pinellas County also has used aerial photography to conduct desktop appraisals, though appraisers there don't use the software employed by Hillsborough.
Pasco County Property Appraiser Mike Wells said he explored the technology several years ago but a test run didn't find many nonpermitted additions. As it is, Pasco appraisers conduct reviews by the more traditional methods: Driving to each parcel and checking from the ground.
Here's how it works in Hillsborough: The property appraiser's office hired a company, Pictometry, to fly over Hillsborough and take high-definition photos. The photos aren't just a bird's-eye view. There are also side-angle, or oblique, shots that can tell whether a new roof is hanging over a porch or room addition, or if a mother-in-law has been built on top of a garage — changes appraisers would not easily see just by walking by a house.
The next step is where Hillsborough is ahead of its counterparts across the state. Appraisers use software called GeoViewPort to analyze the photos and compare the shape of each property to the dimensions recorded in the last appraisal. If the two don't match, it's likely the homeowner made modifications without first getting the proper permits, and the software can highlight those discrepancies for the appraiser.
Not everything caught by the software is a nonpermitted addition. About a quarter of the adjustments in values occurred when the program found a parcel's value actually decreased because a pool was filled in or a shed was removed. In those cases, residents may end up paying less in taxes.
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The property appraiser's office might not be a government agency many would expect to employ airplanes to keep an eye on scofflaws, but it's becoming increasingly common.
The shift accelerated in 2010 when some Florida counties successfully lobbied the Legislature to change appraisal requirements from once in three years to every five years. At the same time, the state allowed counties to conduct aerial appraisals.
"It's probably the most growing, maybe the most exciting technology in our property appraisal field," said Carey Baker, president of the Florida Association of Property Appraisers. "There's still a lot counties that haven't fully adopted it so we have a long way to go before this is considered standard. I think it'll get there."
One hurdle is cost. Hillsborough's four-year contract with Pictometry costs $272,000 a year and the mapping software is another $22,000. Pinellas recently spent about $208,000 on aerial images.
But both counties have found partnerships within government to share the expenses and allow other departments, like public works, to utilize the technology for other purposes. Additionally, Hillsborough recoups some money from the state. Also, cities and agencies like the Southwest Florida Water Management District pick up 25 percent of the tab.
It also saves money on personnel and the gas needed to check every parcel in a growing county. Hillsborough conducted less than half of its reviews in person in the past year. As the technology improves and more competitors enter the market, officials hope the price tag will drop.
"In a perfect world, if cost was no object, you're going to get a better review on the ground, walking around the house," Pinellas County Property Appraiser Pam Dubov said. "But when you live in a world with limited resources, you have to do with what you have, and for us it's been very effective to use the aerial imagery."
Officials are aware that residents might be uncomfortable with government-funded planes taking pictures of neighborhoods and back yards. Henriquez and Dubov were both quick to stress their departments weren't using drones.
Photos are examined before they are made publicly available on the county's website to ensure they don't include shots of people "enjoying their back yard," Henriquez said.
"There are people out there who will think this is a privacy invasion or Big Brother, but in some ways it's a lot less invasive than having somebody come up to their house and look in their back yard without their knowledge," Henriquez said. "There are folks taking pictures from space or from the air all the time, and most of the time it's without them knowing."
There are limitations that will ensure the need for appraisers to visit properties in person. Smaller or sparsely populated counties might find less use for the technology. And the view from the sky isn't always perfect.
Henriquez noted one obstructor that promises to impede the technology for years to come.
"Trees," he said.
Contact Steve Contorno at email@example.com. Follow @scontorno.