Article Legal Notes by Stephen A. McEwen

Code Enforcement by Drone: Critical Considerations Before Launching

Stephen A. McEwen is a partner with the law firm of Burke, Williams & Sorenson LLP and can be reached at

Municipal code enforcement is only as effective as an enforcement officer’s investigation. Because not all potential code violations can be investigated from the public right of way, code enforcement investigations may require access to enclosed or shielded areas of private property. In these more difficult investigatory settings, code enforcement staff may be strongly tempted to rely on emerging drone technology to peer into otherwise inaccessible properties and document nuisance conditions. This particular use of drone technology, however, is sure to raise concerns regarding privacy and the Fourth Amendment.

Unfortunately, case law has not kept pace with the burgeoning drone industry, which has left many code enforcement officers and local officials with numerous questions about what is and is not permissible under the Fourth Amendment. Before using a drone in a nuisance investigation, code enforcement officers should consult their local agency’s legal counsel. In most cases, a warrant will be required before a drone can be used.

The Recent Expansion of Local Governments’ Drone Use

The use of drone technology has expanded exponentially over the past decade. As drones have become cheaper, more efficient and easier to operate, a corresponding expansion has occurred in local governments’ potential uses of drone technology — which include code enforcement.

The Federal Aviation Authority (FAA) has sole authority to regulate United States airspace. The FAA Modernization and Reform Act of 2012 authorizes the FAA to establish requirements and regulations for drones, otherwise known as unmanned aircraft systems (UASs). According to the FAA, a drone is a type of aircraft that operates without onboard pilots or crew.1 The FAA has developed rules for governmental, commercial and private drone usage.2 In general, drones are not permitted to fly over 400 feet above ground level.3 Governmental agencies that wish to operate a drone for public purposes must first obtain from the FAA a certificate of authorization (COA) or waiver, which allows the FAA to conduct a comprehensive operation and safety review.4

After a local government has obtained the necessary COA, drones have innumerable potential governmental uses. Within the realm of law enforcement, drones have been used for accident and crime scene reconstruction, vehicle and suspect pursuits and search and rescue. These particular types of situations often involve emergencies or “exigent circumstances” and therefore typically do not raise Fourth Amendment issues. The potential use of drones for aerial surveillance and investigation by code enforcement officers, however, directly implicates the Fourth Amendment.

Fourth Amendment Considerations

The Fourth Amendment prohibits unreasonable searches and seizures by government agents without a warrant and applies with the same force to investigations and administrative searches by code enforcement officers as it does to searches and seizures by the police or other law enforcement agencies.5 The amendment states:

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

The question of whether a search is subject to the Fourth Amendment depends on whether there is a reasonable expectation of privacy in the place to be searched. To determine if a person has a reasonable expectation of privacy, courts employ a two-part test articulated by the U.S. Supreme Court in Katz v. United States (1967).6 The test “asks first whether the person has manifested a subjective expectation of privacy in the object of the challenged search, and second whether society is willing to recognize that expectation as reasonable.”7

Courts apply the highest level of Fourth Amendment protection to those areas within a private residence and the residence’s “curtilage,” which is the area immediately adjacent to and surrounding the home. What constitutes the curtilage is determined on a case-by-case basis and depends on the proximity of the area to the home, the presence of any enclosures around the area in question, the nature of the area’s uses and the steps taken by the resident to shield the area from observation.8 The Fourth Amendment also applies to commercial businesses, particularly private areas that are not open to the public.9

The Plain View Doctrine

The plain view doctrine is an exception to the Fourth Amendment that permits law enforcement officers to make observations from public places or neighboring properties without obtaining a warrant. For example, California appellate courts have held that viewing marijuana plants from a neighbor’s second story window did not violate the Fourth Amendment10 and that an officer did not act unreasonably when he peeked over a fence from a neighboring property.11 In both of these situations, the appellate court was persuaded by the fact that the officers had a lawful right to be where they were when they made the disputed observations.

The appellate courts have not yet addressed whether the use of drone technology falls within the plain view doctrine in the context of either code enforcement or police searches. However, in the following cases, the U.S. Supreme Court has addressed the Fourth Amendment implications of using airplanes and helicopters to gather evidence of criminal violations:

  • In California v. Ciraolo (1986),12 the court held that a warrantless aerial observation from an airplane flying in navigable airspace at 1,000 feet above a fenced-in backyard did not violate the Fourth Amendment. The court concluded that there was no reasonable expectation of privacy in an uncovered backyard that was visible from navigable airspace to any person flying over the property.
  • In Dow Chemical Co. v. United States (1986),13 the court held that the Environmental Protection Agency’s use of aerial photography from an airplane flying in navigable airspace at least 1,200 feet above a highly secure industrial facility did not require a warrant. The court noted that the camera used by the government was a “commercial camera commonly used in mapmaking” and was not a “unique sensory device” that could record conversations inside Dow’s buildings or reveal such “intimate details as to raise constitutional concerns.”
  • In Florida v. Riley (1989),14 in a plurality decision, the court held that there was no Fourth Amendment violation when law enforcement used a helicopter flying in navigable airspace 400 feet above the ground to observe a greenhouse that was being used to cultivate cannabis.

A California appellate court also applied the U.S. Supreme Court’s decision in Florida v. Riley to a “general, random, helicopter surveillance” of rural properties in the case of People v. McKim (1989). In that case, two officers were operating a helicopter in a grid pattern at approximately 400 feet when one of them spotted cannabis plants growing on the defendant’s property. Based on this aerial observation, the officers obtained a search warrant. The trial court concluded that flying under 500 feet, which was the lowest permissible altitude for fixed-wing aircraft, was per se unreasonable but the court of appeal reversed based on Florida v. Riley and held that warrantless aerial observations from at least 400 feet did not automatically violate the Fourth Amendment. The court noted that there was “no evidence … that the helicopter surveillance over defendant’s residence interfered with defendant’s use of his property, or revealed intimate details connected with the use of his home or curtilage, or created any undue noise, wind, dust or threat of injury.”15

Does the plain view doctrine apply to the use of drones for surveillance and investigation?

It is difficult to predict whether courts will apply these cases to the use of drones for surveillance and investigation, but it seems safe to conclude that drones raise entirely new issues that airplanes and helicopters do not. The concept of navigable airspace that figured prominently (but was not necessarily determinative) in the plain view cases discussed in the preceding section will probably have little application to drones, which can fly safely and relatively undetected at much lower altitudes than conventional aircraft and can enter confined spaces and record images and sounds in ways that would be impossible for airplanes or helicopters. Rather, it is likely that the potential intrusiveness of drone technology will guide the Fourth Amendment analysis. When it comes to drones, therefore, we must look to Katz v. United States and ask whether the expectation of privacy under any particular set of circumstances involving a drone is one “that society is prepared to recognize as ‘reasonable.’”

Justice Sandra Day O’Connor’s concurring opinion in Florida v. Riley may be instructive. In that case, she observed that the court found no Fourth Amendment violation in California v. Ciraolo “because public air travel at 1,000 feet is a sufficiently routine part of modern life that it is unreasonable for persons on the ground to expect that their curtilage will not be observed from the air at that altitude.” With regard to the use of a helicopter, she concluded that “there is reason to believe that there is considerable public use of airspace at altitudes of 400 feet and above” and that, as a result, any expectation that the property owner’s backyard greenhouse would remain private was unreasonable.

Under this approach, it is probable that a warrant will be required for drones in most investigatory situations. While the use of drones in public places has become very common and popular, there has not been considerable use of low-flying drones over private properties, as was the case with airplanes and helicopters. In fact, the public has expressed significant concern over possible privacy intrusions made by both privately and publicly operated drones.16 It is likely that a court would conclude that a resident’s expectation of privacy from low-flying drones that can make high-resolution observations is “one that society is prepared to recognize as reasonable.”17

Additional Considerations

Code enforcement officers should also check the local regulations, if any exist, on drones. If the jurisdiction restricts the use of drones above residential, commercial or industrial properties, such restrictions may be a critical factor in determining whether the expectation of privacy is reasonable. Even if there are no local drone regulations in effect, the potential for unreasonable privacy intrusions by increasingly sophisticated drone technology will likely tip the scales in favor of requiring a warrant for the use of drones in code enforcement investigations.

The better practice, therefore, is for code enforcement officers to simply obtain an administrative inspection warrant under California Code of Civil Procedure Section 1822.50 et seq. before using a drone to conduct an investigation. The process for obtaining an inspection warrant is relatively straightforward. Unlike criminal search warrants under California Penal Code Section 1524, which require a showing of probable cause, inspection warrants under the California Code of Civil Procedure generally require a lesser showing of reasonable cause, which is typically defined as some plausible basis for believing that a violation is likely to be found that justifies further investigation or testing. It is worth noting that inspections conducted pursuant to a warrant are presumptively valid and should, in most cases, shield the local agency and its officers from liability.


Flying a drone over a problem property is undoubtedly an easy and effective way to evaluate and document the scope of a public nuisance and to provide up-close, aerial comparisons with neighboring properties. However, code enforcement officers must take the Fourth Amendment into careful consideration before implementing this technology. In most nuisance abatement situations, this will require a proper warrant.

Related Resources

Preparing for the Drone Age in Your City: Potential Benefits and Issues

Drones: A Growing Hazard in the Absence of Tighter Regulations

2019 Legislative Year in Review

About Legal Notes

This column is provided as general information and not as legal advice. The law is constantly evolving, and attorneys can and do disagree about what the law requires. Local agencies interested in determining how the law applies in a particular situation should consult their local agency attorneys.

[1] 72 Fed. Reg. 6689 (Feb. 13, 2007)

[2] Federal Aviation Administration, “Fact Sheet: Unmanned Aircraft Systems (UAS),”

[3] 14 CFR § 107.51

[4] Federal Aviation Administration, “Fact Sheet: Unmanned Aircraft Systems (UAS),”

[5] Camera v. Municipal Court (1967) 387 U.S. 523, 534; See v. City of Seattle (1967) 387 U.S. 541, 545-546.

[6] (1967) 389 U.S. 347

[7] People v. McKim (1989) 214 Cal.App.3d 766, 769.

[8] United States v. Dunn (1987) 480 U.S. 294.

[9] Patel v. City of Montclair (9th Cir. 2015) 798 F.3rd 895.

[10] Dillon v. Superior Court (1972) 7 Cal.3d 305.

[11] People v. Claeys (2002) 97 Cal.App.4th 55.

[12] California v. Ciraolo (1986) 476 U.S. 207

[13] Dow Chemical Co. v. United States (1986) 476 U.S. 227

[14] Florida v. Riley (1989) 488 U.S. 445

[15] People v. McKim, supra, 214 Cal.App.3d at p. 772.

[16] “Eyes In The Sky: The Public Has Privacy Concerns Over Drones,” Steven Rice, Forbes Magazine, Feb. 4, 2019.

[17] Katz v. United States, supra, 389 U.S. at p. 361.