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How Cops Find Grow Houses

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Grow House Detection Methods And The Law

Even though weed has been legalized and is no longer considered to be taboo by society; weed is still illegal and catching illicit marijuana grow operations is a priority for many law enforcement agencies. First of all, forfeiture laws, which can result in loss of property even without a conviction, incentivize the police to find marijuana grow houses. Also, even if you are just growing marijuana for yourself, your grow room is not safe from the police as police helicopters have even arrested an 81-year old grandmother who was only growing a single plant.

So, the question that needs to be addressed is, how do cops find indoor growing operations?

How Do Cops Find Grow Houses?


A tip of a grow home is typically the first step toward the police investigating property for being a potential indoor growing operation. Once the police receive that tip, the investigation will likely soon follow.

Below is a summary of the few most common methods that cops use to gather evidence of potential grow houses.

Unusually High Electricity Bill

A high power bill can indicate an indoor growing house, and energy companies seeing an unusually high power bill may report you to the police. Whether or not you are reported depends upon your energy providers or where you live. Once the police get this tip, they may be able to get a warrant to either search your home or further investigate your home for a growing operation. Many growers will tap into the main power cable, bypass the meter, and steal electricity. They save money on electricity, and energy companies cannot detect excess utility use.

Is This Legal? You may wonder if it is legal for a Power company, without your permission, to give law enforcement your energy use information. The answer is, unfortunately, yes. Unlike medical records and HIPA, your energy and utility use is not considered private. Therefore, the utility companies can report you using excess electricity even when you were not stealing power or trying to somehow bypass the electric meter. 

Suspicious Activity

This is especially true for a suburb or city growing operation. A typical house in a suburban or city location will not look like a survival bunker or compound. For example, it will not have blacked out windows,” Beware of Dog” sign with no dog, etc. Of course, these signs could indicate paranoia or just someone wanting to be extra safe.

Abnormal Living Conditions

Many grow houses are dedicated to just growing cannabis and do not have the typical signs of living at the house. For example, does the neighbor see you bringing in groceries? Are people coming and going from the house like they are going to and leaving their job or does it look like any normal house would look like?


Of course, the smell of weed is an obvious sign of a grow house. That is why a quality Co2, filter is essential.


Electrical lights and the sound of fans outside of the house.


Humidity needs to be kept at a certain level when growing. As a result, because of excess humidity, the windows may be fogged over.

Thermal, Infrared, Cameras

Police use helicopters to discover excessive heat coming from a house. This is addressed further below.

These are just a few of the signs that indicate a grow room. For the full list, CLICK HERE.

Other than perhaps excess heat, just one of these signs will likely not be the reason for a search warrant being issued. However, the more signs of a grow house, the more likely a warrant will be issued.

Infrared Tech and Law Enforcement

Law enforcement started to use infrared, thermal cameras in the 1990s, and has been used for some of the following tasks:

● Capture Criminals-No matter how dark it is or how hidden he or she is, a thermal camera can find hiding criminal suspects.

● Hidden Objects-An IR camera can find secret compartments in structures that may contain illegal contraband.

● Many, other uses . . . CLICK HERE, for the complete list.

And, of course, a thermal, heat detection camera can detect grow room’s electric heat signature. ( Heat Signatures is the thermal heat that an object gives off. I.E., HID grow lighting)

How Do Thermal Cameras Work?

Every living object emits heat or infrared radiation, and thermal cameras can detect this heat. A general rule is that the warmer an object is, the more I.R. radiation it will give off. Grow houses and grow room equipment, especially when they use HID growl lights, give off a tremendous amount of heat. That is easily detected by thermal cameras. The heat that an object gives off is called a “Heat Signature.” Because of the grow lights (particularly HID lights), a grow house will be much hotter than a non-grow house. Therefore, excess heat indicates that unusual activity is going on in a house, “could be a grow house.

That evidence received from the camera is then used by the police for probable cause to get a warrant. Upon getting a warrant the cops will be able to go inside your property to search and find your cannabis plants.

Is It Legal For Police To Use Helicopters to Detect Weed?

Police Helicopter

The answer is going to anger you: “It Depends.” First of all, if you are growing traditionally outdoors with no greenhouse, the U.S. Supreme court has deemed that it is NOT legal for a helicopter to search for weed. The decision was decided in Florida V. Riley, where an arrest was considered lawful when a police helicopter saw plants grown in a greenhouse. The police, via a tip, suspected that a house was the sight of a growing operation. They could not see any weed at street level as the greenhouse windows were covered. So, the police then used a helicopter to search for weed. Cannabis plants were subsequently seen through two missing panels on the roof that a helicopter could only see.

In this case, no warrant was needed as the plants were considered to be in plain view.

On the other hand, cannabis plants inside a house are not considered plain view. Therefore, without first getting a warrant, the police cannot use a thermal camera to detect an indoor growing operation. (Assuming that law enforcement does not have any other reputable evidence that you are illegally growing)  Kylo v. the United States is the case.

Why Is a Warrant Needed?   

If your plants are hidden in your house, a police officer, without other evidence, cannot search your house for a growing operation by using a thermal, I.R., camera.

Per the U.S. Supreme court, Kylo v. the United States using infrared cameras to search for a suspected growing house is considered to be a search. The fourth amendment requires that there must be a probable cause of a search. This means cops must have a reasonable suspicion that a crime is being committed before a warrant can be issued.  Therefore, as thermal cameras are legally a search, a search warrant is needed.

As state earlier, several other signs can indicate a grow room. For example, a utility company reports you for using too much electricity, or a neighbor reports you for suspicious activity. Therefore, it is likely not that hard to get a search warrant issued. 

Can Helicopters Spot one Plant?

One Plant



The answer is yes. And it depends upon how lucky or unlucky you are or whether you were just in the wrong place at the right time. A joint operation (several other plants from other individuals were also confiscated) between stated police and national guard helicopter discovered and took a single plant that was grown by an 81-year old woman for medical purposes. The single pot plant was in plain sight in her garden.

How Can I Prevent This?


My first suggestion, which of course is impractical for the vast majority, and may seem like a smart ass answer. But, to be safer, you could move where it is legal to grow weed. Don’t assume though that you can grow weed just because the state sells weed in dispensaries. For example, in Nevada, weed is legal, both recreationally and for medical use. But, unless you live 25 miles away from a licensed dispensary, it is illegal for you to grow. So, be sure to get competent legal advice concerning the laws on cannabis growing before you decide to move.

LED Lights

Using LED grow lights will not shield you from law enforcement thermal imaging cameras. However, LED lights do give off less heat, which means that electricity will be used less, which will mean you will have a lesser chance of being detected.

Use Heat Signature Shields Technology-Do Grow Tents Stop Helicopter Detecting Heat?

If you are serious about blocking your heat signature, you should look into heat shielding fabric. One such fabric is C3 Anti-Detection Foil, which can be used on grow tents. I have an entire article on C3 material.

Final Thoughts

Thermal image or heat detection, I.R., cameras are just one bit of technology currently used to detect illegal grow houses. And more advanced surveillance and tech are being made as this article is being written. Just because you purchased a guaranteed product now to shield your heat signature does not mean that the same product will work in ten years.

Suppose you are not able to move where you can legally grow. In that case, you need to make a cost-benefit analysis on whether or not you are willing to be punished for a growing. The home grower also needs to make sure to know the cannabis cultivation laws where they live. For example, in some areas, a one plant difference could mean the difference between a misdemeanor and a felony.


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