How Far Should a Generator Be From the House? The 20-Foot Rule

The minimum distance

CDC and CPSC tell consumers to use portable generators outside and at least 20 feet from homes or from doors, windows, and vents. Treat 20 feet as a minimum, not a target that overrides the rest of the site. Exhaust must face away from the building, and the unit must not sit where wind or a nearby wall channels fumes back toward an opening. Measure from the generator to the nearest relevant opening, not merely to a property line or garage door.

Carbon monoxide is colorless and odorless, so smell and open windows cannot confirm safety. One portable generator can produce a large amount of CO. People who are sleeping may be overcome before recognizing symptoms. The placement rule works with CO alarms and safe operating practices; it does not replace them. If the property cannot provide a compliant outdoor location, choose a non-combustion backup plan or leave during the outage.^[1][3]

Spaces that are still indoors

Never run a portable generator in a home, basement, attached or detached garage, carport, crawlspace, shed, porch, tent, or other enclosed or partly enclosed space. Opening a garage door does not turn the garage into an outdoor location. Exhaust can accumulate and enter through doors, attic paths, soffits, shared walls, or air leaks. A remote corner of a large garage is not an exception to the 20-foot outdoor guidance.

Do not place the unit under a window, next to a dryer or combustion-air vent, beside a neighboring opening, or in a narrow courtyard that traps exhaust. Look at the whole building, including basement windows, pet doors, fresh-air intakes, and temporarily open windows. Discuss property-line and noise rules with local authorities, but never solve a neighbor concern by moving the generator closer to your own occupied space.^[2][3]

Exhaust direction and wind

CPSC adds that exhaust should face away from the home. Mark the exhaust side before an outage and position the machine so hot gases and sparks do not point toward buildings, dry vegetation, fuel, people, or cords. Wind direction can change and does not make a too-close location safe. Recheck nearby openings whenever the generator is moved or when storm preparations change doors and windows.

Do not build an improvised box to control noise or rain. An enclosure can trap CO, overheat the engine, restrict cooling, or create a fire hazard. Use only a manufacturer-approved outdoor operating cover or shelter with the required clearances and ventilation. Keep the surface stable and above water flow. If rain or flooding cannot be managed without enclosure or wet contact, shut down and use another plan.^[3][1]

Long cords are part of safe distance

CDC advises using an extension cord longer than 20 feet so the generator can remain at a safe distance. CPSC says cords should be heavy-duty, designed for outdoor use, long enough for remote placement, intact, grounded, and rated above the connected wattage. Length increases voltage drop, so choose gauge and rating from the generator and appliance instructions rather than connecting several household cords end to end.

Keep connectors dry and off wet ground, protect cords from traffic and sharp edges, and do not pinch them through doors or windows. Label each cord for its intended load and inspect it before every use. A hot plug, discolored insulation, unstable appliance, repeated trip, or damaged ground pin is a stop signal. Permanent household circuits require approved transfer equipment, not a long cord plugged into a wall outlet.^[2][4]

CO alarms and symptom response

CPSC recommends battery-operated CO alarms or alarms with battery backup on every home level and outside sleeping areas; interconnected alarms provide broader warning. Test alarms and replace batteries or units according to their instructions before storm season. An alarm is a last line of warning, not permission to reduce generator distance. Never disable an alarm because it sounds during operation.

Common CO-poisoning symptoms include headache, dizziness, weakness, nausea, vomiting, sleepiness, chest pain, and confusion. If an alarm sounds or symptoms occur, get everyone and pets into fresh air immediately and call 911. Do not reenter to turn off equipment when that requires exposure; tell emergency responders that a generator is operating. People who have been sleeping or drinking alcohol may not notice early symptoms.^[3][2]

Fuel, heat, electricity, and security

Distance addresses exhaust entry but not every generator hazard. Shut down and allow the engine to cool before refueling. Store fuel in approved containers away from living areas and ignition sources. Keep the generator dry, operate it with dry hands, and use GFCI and grounding arrangements required by the manual. Directly connected loads need rated cords; household wiring needs professionally installed transfer equipment.

Secure the unit against theft without blocking cooling or exhaust. Keep children and pets beyond a clear boundary. Do not operate near dry vegetation, combustible storage, or where floodwater can rise. Service oil, filters, spark arrestor, battery, and fuel system on schedule. A machine that has been stored for years without testing should not become the household's only plan hours before a hurricane.^[4][2]

Map the location before the outage

Choose and measure the location in daylight. Mark 20 feet from every opening, confirm exhaust direction, stable ground, drainage, weather protection, cord paths, fuel handling, security, noise constraints, and safe access. Photograph the final setup and keep a simple diagram with the generator. Test priority loads without exceeding ratings and confirm that CO alarms remain powered during an outage.

Review the map after renovations, new windows, HVAC work, fences, or a different generator. Train all operators, including the rule that indoor placement is never allowed. If no suitable point exists or weather makes deployment unsafe, stop. A hotel, cooling or warming center, friend’s home, or correctly sized battery system is better than operating a combustion engine where exhaust can reach occupants.

Include neighbors and attached structures in the map. Exhaust that misses your own window can still enter an adjacent home, apartment, camper, or occupied garage. Coordinate safe spacing before a widespread outage when many generators may run simultaneously, and never relocate a running unit while hot or connected. Shut down, cool, disconnect, and reassess the complete route first. Repeat the full safety check after every move and setup. Record the approved location in the household outage plan so nobody improvises a closer placement during bad weather.^[1][3][4]