Safe in the air, clean at the drain
Drone cleaning takes workers off ropes and stages, and adds aviation, hose and runoff risks that must be planned. Here is how the rules fit together in Canada and the United States.
Why take people off the wall
Traditional high-level cleaning puts a person where a fall kills. In British Columbia, WorkSafeBC requires fall protection where a worker could fall 3 m or more, prefers guardrails, then fall restraint, then fall arrest, and requires a written fall protection plan for work at 7.5 m or higher without permanent guardrails. Rope access and suspended stages depend on roof anchors that must be inspected and certified. Other provinces set similar requirements, and in the US, OSHA's walking-working surfaces rules govern rope descent systems and their anchorages.
A cleaning drone keeps the crew on the ground. That removes the fall hazard for the cleaning itself. It does not remove every hazard: someone may still need roof access to place a hose or check a parapet, and that work follows the same fall protection rules. Compare the methods in drone versus rope access.
The rules a cleaning flight sits under
| Question | Canada (Transport Canada, CARs Part IX) | United States (FAA) |
|---|---|---|
| Pilot qualification | Basic or Advanced pilot certificate by operation; Advanced for flights near bystanders or in controlled airspace. Since November 2025, Advanced pilots may fly medium drones (over 25 kg up to 150 kg) within visual line of sight, subject to the aircraft requirements. | Remote pilot certificate under Part 107 for aircraft under 55 lb. Heavier aircraft need an exemption and registration under other rules. |
| Near airports and in controlled airspace | Authorization from NAV CANADA, requested through its drone portal. | Authorization, commonly through LAANC or FAA DroneZone. |
| Height | Generally no higher than 122 m above ground without a special flight operations certificate. | 400 ft above ground, or up to 400 ft above a structure when within 400 ft of it. |
| People below | Distance and overflight limits depend on the certificate and the aircraft's safety declaration. | Operations over people are limited by aircraft category and rules; closures avoid the question. |
| Liquid payloads | Dangerous or hazardous payloads need a special flight operations certificate, and no pilot may create a hazard by dropping anything. Check how your product is classified. | Part 107 prohibits carrying hazardous materials. Dispensing pesticides or other economic poisons brings in Part 137 and exemptions. Water is generally not a Part 137 substance. |
| Tethers | A tether does not take the flight outside the rules, and Transport Canada has said tethering to avoid a special certificate is not acceptable. | Tethered drones are still flown under the drone rules. |
What is actually being sprayed
Most glass work sprays only purified water, which is the simplest case under both rule sets. Soft wash solutions are different: dilute sodium hypochlorite, surfactants and other cleaners each come with a safety data sheet, and the classification of the product as mixed and delivered matters to the aviation rules as well as to workplace chemical rules such as WHMIS in Canada and OSHA hazard communication in the US. Because the solution is pumped up a hose from the ground, the aircraft itself carries very little, which is part of why tethered systems are used.
Moss killers are pesticides, regulated by Health Canada and the EPA, and used only as their labels allow. Health Canada began permitting drone application in 2026 only for products registered for aerial use. We treat each product as its own question, and we check the current rules before every season because they are changing. For the wider picture see drone rules in Canada and in the United States.
Where the water goes
Storm drains in most Canadian and US cities carry water straight to creeks, harbours and the ocean without treatment. That is why municipal bylaws, and in the US the local permits that sit under the Clean Water Act, restrict what goes into them. The Capital Regional District's guidance for power washing is typical: plain water on unpainted surfaces can go to landscaping, water carrying cleaners should be collected and sent to the sanitary sewer, caustic wash water must be neutralized first, paint chips filtered out, and storm drains found and protected with berms or covers before work starts.
For a drone job that means the drain map is part of the site assessment, pure water is used wherever it does the job, solutions are chosen for the surface and the runoff, and landscaping is pre-wetted or covered when a bleach-based wash is used. The plan says where every litre ends up.
The safety plan for a cleaning day
Site survey
Airspace, obstacles, wires, trees, wind patterns around the building, people and vehicles below. Canadian rules require a site survey before operations, and it is good practice everywhere. See preparing a site for a flight.
Ground closure
The area under the working face closed with barriers and a spotter, including entries and sidewalks, with city permission where public land is used.
Hose and skid
Hose routed so no one trips over it or drives on it, pressure checked, chemical handling with protective equipment and safety data sheets on site.
Drains and plants
Storm drains covered, collection set up, plants protected.
Weather limits
Wind, rain and temperature limits set in advance, and the job stops when they are reached.
Emergency plan
What happens if the aircraft loses power or the hose snags: the fall zone is already clear.
The risks drone cleaning adds
Spray drift
Wind carries mist onto cars, people and neighbouring property.
Loss of control near a wall
Turbulence and gusts are strongest around corners and rooftops.
Wrong product on the wrong surface
Some cleaners etch glass coatings, stain metals or harm plants.
Questions
Is it legal to spray water from a drone in Canada?
There is no rule against a drone spraying water as such. The pilot must hold the right certificate, stay within the height and airspace rules, keep safe distances from people and not create a hazard. Hazardous payloads need a special flight operations certificate.
Do you need Part 137 to clean buildings with a drone in the US?
Part 137 covers dispensing economic poisons and agricultural substances. Spraying water to clean a building generally falls under Part 107, while dispensing a pesticide such as a moss killer can bring Part 137 into play. Check with the FAA for your specific product.
Can wash water go into the storm drain?
In most municipalities, only rainwater should go into storm drains. Water carrying cleaners is collected and sent to the sanitary sewer where allowed. Check your local bylaw.
Is drone window cleaning safer than rope access?
It removes the fall hazard for the cleaning itself, the biggest risk in high-level work. It adds aviation and ground hazards that are managed with closures, weather limits and certified pilots.
Does a tethered drone need a pilot certificate?
Yes. A tether does not take a drone outside the rules in Canada or the United States.
What chemicals are used in drone soft washing?
Usually a dilute sodium hypochlorite solution with a surfactant for organic growth, or a mild detergent for grime, followed by a pure water rinse. Glass is mostly cleaned with pure water only.
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