From the air and on the ground, the city has taken unprecedented steps to inspect a controversial off-the-grid agricultural development in Kunia, using a team of experts from multiple agencies to search the sprawling project for illegal buildings, grading, sewage systems and other unauthorized structures or activities.

The effort included a recent aerial survey aboard a Honolulu Fire Department helicopter to pinpoint locations of main structures within Kunia Loa Ridge Farmlands.

The project, tucked along the foothills about a mile off Kunia Road and several miles from the H-1 freeway, has no addresses, street names or directional signs and is supposed to be limited to agribusiness activities.

But it has become a hub for unregulated construction, with people living in illegal homes along the dirt roads that snake through the hilly, remote terrain.

Twenty-three inspectors from the Department of Planning and Permitting, HFD and the state Department of Health began a section-by-section check of the 854-acre development Tuesday, and by week’s end had covered the entire project.

Planning Director George Atta said he was unaware of an inspection effort of this magnitude conducted previously by his department.

“For us it’s a big operation,” Atta told the Honolulu Star-Advertiser. The city expects citations to be issued starting in June.

The stepped-up effort comes in the wake of Star-Advertiser coverage over the past two years chronicling the proliferation of unregulated construction at Kunia Loa, which was designed to provide diversified agricultural opportunities for small farmers.

Dozens of houselike structures have sprung up there, including some with balconies and large windows capitalizing on stunning views of Pearl Harbor and Diamond Head in the distance.

Some structures have been used as dwellings and vacation rentals despite a state law and Kunia Loa’s own rules prohibiting residential use. The development is not connected to Oahu’s power, water, sewage and telephone grids.

The Star-Advertiser’s prior coverage also disclosed the existence of a Buddhist temple, church and a dog day-care business at the project, enhancing its reputation as a place where internal and external oversight has been lax.

The city’s inability thus far to do much about the unregulated construction has been attributed in part to the 2012 state law that authorized building-permit exemptions for certain agricultural structures while prohibiting residential use. The counties are charged with enforcing the law.

But the city previously said its enforcement tools were inadequate for a project as unusual as Kunia Loa, which is privately owned by a nonprofit cooperative and is considered by the city as one giant parcel, not individually owned lots.

The continuing controversy frustrated Mayor Kirk Caldwell and led to the development of the new, more aggressive enforcement approach.

An important element is the use of satellite-based navigation technology to get precise building locations. Inspectors used what was plotted from the air in a single afternoon in early May to compare with records the city has for existing structures at Kunia Loa.

Atta said the effort marks the first time his agency has taken to the skies to get location coordinates for enforcement.

While the 2012 state law provides building-code exemptions for qualified agricultural structures, such as tool sheds and storage buildings under 1,000 square feet, it requires owners or users of the buildings to notify the planning and fire departments within 30 days of completion. The notification must include the structure’s location, size and type, and if the information is not provided within the 30 days, the city says it has the authority to void the exemption.

DPP officials say the agency has received only a few such notifications for Kunia Loa buildings constructed without permits. About 45 structures were built with permits and are not the problem, according to Atta.

Based on what was seen in the aerial inspection, the city has determined that numerous structures were constructed without permits. It did not have an estimate.

After the flyover inspection, the city told Kunia Loa’s owner — an association of farmers and others who bought membership interests in the nonprofit, giving them proprietary leases for specific parcels — that it had 30 days to provide the required notifications.

If the information isn’t supplied within that time frame, the city expects to start issuing violation notices, according to Atta. Its inspectors also are looking for such things as fire, grading and electrical code violations that are not linked to the exemption law.

The Health Department is checking for individual wastewater systems, such as septic tanks. Because residential use is not allowed at Kunia Loa, no such systems are permitted there.

But Janice Okubo, a spokeswoman for the department, said the state inspector who accompanied the city’s team last week saw evidence of unapproved wastewater systems that may have been in use. Gaining access into the structures to verify such use remains a challenge, she said in an email.

Atta and the association’s attorney, Christopher Shea Goodwin, said the group has been cooperating with the city and state investigations.

“Neither Kunia Loa Ridge Farmlands nor its board of directors has authorized the erection of any structure or the conducting of any activity in violation of any applicable law, ordinance or the project’s governing documents,” Goodwin said in a statement to the Star-Advertiser.

Asked about the city’s stepped-up enforcement, Randy Cabral, president of the Hawaii Farm Bureau, which lobbied for the exemption law, said the statute was clear.

“It only allows farmers to build necessary, non-residential buildings such as greenhouses and crop and farm equipment storage, with appropriate restrictions to ensure safety and protect health and the environment,” Cabral said in an email. “Those who do not comply with the law should not be surprised by enforcement action.”

Atta, who was surprised by the number of structures seen in the video and photos taken during the aerial survey, told the Star-Advertiser the inspections will give the city a better handle on what’s happening at Kunia Loa. “Earlier, we didn’t have a good grasp on the scale of overall activity that was out there,” he said.

Donna Leong, the city’s top civil attorney, said the intent of the enforcement action is to ensure that “this land is really used for diversified agriculture.”

Pepe Paguirigan, who has a 12-acre lot in Kunia Loa, welcomed the city’s more aggressive approach but questioned why it took so long, given the project’s launch in 2010. The pace of building, however, didn’t accelerate until after legislators approved the 2012 exemption law, which the city opposed.

“This (enforcement) should have been applied from Day One so we wouldn’t have this kind of problem today,” Paguirigan said.