---
title: "Portable Generator 20-Foot Rule for U.S. Outages"
locale: en
category: knowledge_base
category_name: "Knowledge Base"
translation_status: reviewed
license: cc_by
author: "Injoys Editorial Team"
source_url: https://injoys.com/en/articles/portable-generator-20-foot-rule-us-hurricane-safety
published_at: 2026-09-18T00:39:57+09:00
---

# Portable Generator 20-Foot Rule for U.S. Outages

> Fuel-powered portable generators must be placed outdoors at least 20 feet from doors, windows, and vents. This explains alarm placement and emergency contact guidelines for U.S. power outages, as well as how to prepare for power gaps affecting medical devices.

## Key Points

- The CDC advises placing fuel-powered generators outdoors at least 20 feet from doors, windows, and vents.
- Opening the garage door or turning on a fan does not make indoor generator use safe.
- CO alarms must work during power outages and be installed on every level of the home and outside sleeping areas.
- If a CO alarm sounds or poisoning is suspected, evacuate outdoors immediately and then call 911 in the United States.
- Households that use medical devices must plan for power gaps during refueling and cooling, as well as power during evacuation.

Fuel-powered portable generators must be placed outdoors at least 20 feet away from doors, windows, and vents. Indoor use is prohibited even if the garage door is open. If a carbon monoxide alarm sounds or poisoning is suspected, evacuate outdoors immediately.

The 20-foot standard is based on CDC power outage guidance that completed expert review on August 26, 2026.

## What the 20-Foot Standard for Portable Generators Means

Twenty feet is the minimum distance needed to reduce the risk of exhaust entering the home. The exact metric conversion is 6.096m. Simply placing a generator outdoors does not guarantee safety.

The [CDC power outage guidance](https://cdc.gov/natural-disasters/response/what-to-do-protect-yourself-during-a-power-outage.html) specifies the distance from doors, windows, and vents. CPSC requires at least 20 feet from homes and buildings. The exhaust must face away from openings in nearby buildings.

### Comparison of Distance Recommendations by Agency

NIST recommends a distance of 25 feet, which is farther than 20 feet. This does not mean that all risk disappears once 20 feet is secured. The distance and exhaust direction specified in each document must be considered together.

| Agency and document | Distance recommendation | Additional condition to check |
|---|---|---|
| CDC power outage safety guidance, reviewed August 26, 2026 | At least 20 feet from doors, windows, and vents | Outdoor use |
| CPSC hurricane safety announcement, May 27, 2026 | At least 20 feet from homes and buildings | Exhaust faces away from doors, windows, and vents |
| NIST Generator Safety | At least 25 feet from the home | Position so exhaust does not face open doors, windows, or vents |

The exact conversion of 25 feet is 7.62m. The NIST guidance lists it as 7.6m. This comparison covers safety recommendations for portable generators. Separate standards are needed when determining the installation of permanently installed standby generators. [NIST Generator Safety](https://www.nist.gov/social-media/generator-safety)

## Why a Generator Cannot Be Used Even With the Garage Door Open

Carbon monoxide can build up even in a partially enclosed space such as a garage with the door open. Carbon monoxide is a colorless, odorless toxic gas. Exposure can occur even when no exhaust odor is noticeable.

CDC's notice linking to the Generator Safety Fact Sheet states:

> Never use a generator inside your home or garage, even if doors and windows are open.

This means a generator must not be used inside a home or garage even when doors or windows are open. Ventilation using a fan does not override this prohibition. Basements and sheds are also not acceptable places for use. [CDC generator safety guidance](https://www.cdc.gov/carbon-monoxide/media/pdfs/Generators_1.pdf)

## Installation Conditions by Location

Whether a generator can be installed must be determined by considering both your home and neighboring buildings. EPA advises placing it outdoors away from all homes. Balconies and porches are also included among prohibited locations. [EPA generator placement guidance](https://www.epa.gov/emergencies-iaq/where-safely-use-fuel-powered-portable-generator-infographic)

| Location or situation | Assessment | Reason or additional condition |
|---|---|---|
| Open garage, basement, or shed | Use prohibited | Space where CO can accumulate |
| Apartment balcony, home deck, or porch | Use prohibited | Location close to buildings and openings |
| Far from your home but close to a neighbor's window | Unsuitable placement | Risk of exhaust entering the neighbor's home |
| Open yard sufficiently far from buildings | Use after checking conditions | Check distance, exhaust direction, and flood risk together |
| Property where a safe distance cannot be secured | Consider another power source or evacuation location | A condition that cannot be resolved by moving the generator indoors |

This table applies agency placement guidance to residential situations. A small property does not reduce the distance requirement. In multifamily housing, a balcony must not be treated as an emergency generator space.

## CO Alarm Placement and Automatic Shutoff

CO alarms must be able to operate during a power outage. Battery-powered models and models with battery backup meet this requirement. CPSC recommends installing them on every level of the home and outside sleeping areas.

- Test each alarm every month.
- Replace batteries when needed.
- With interconnected alarms, an alarm from one unit is transmitted to the others.
- Follow the product manual for specific installation locations.

Some generators automatically stop when the surrounding CO concentration becomes dangerous. CPSC recommends products with this automatic CO shutoff feature. This feature does not permit indoor use. Separate indoor alarms are still needed. [CPSC 2026 hurricane safety announcement](https://www.cpsc.gov/Newsroom/News-Releases/2026/CPSC-Warns-of-Generator-Carbon-Monoxide-and-Fire-Hazards-Ahead-of-Hurricane-Season)

## Carbon Monoxide Symptoms and U.S. Emergency Contact Guidelines

If CO poisoning is suspected, move immediately to fresh air. Symptoms may include headache, dizziness, nausea, vomiting, and weakness. Chest pain and confusion are also known symptoms. A sleeping person may not notice the symptoms.

If several people become ill at the same time, suspect a shared exposure. Symptoms that improve after going outdoors can also be a clue. This change alone cannot confirm or rule out poisoning. [Poison Control carbon monoxide guidance](https://www.poison.org/articles/carbon-monoxide)

1. If an alarm sounds or poisoning is suspected, evacuate the building immediately.
2. If an alarm sounds, call 911 from a safe location outdoors.
3. If anyone has decreased consciousness, difficulty breathing, or seizures, call 911 without delay.
4. For other exposure consultations, call 1-800-222-1222 after evacuating.

1-800-222-1222 connects callers to a U.S. poison control center. Do not delay evacuation or an emergency call while waiting for a consultation. Do not reenter the building to look for the cause. Follow the responding fire department's safety clearance before reentry. [Poison Control first aid guidance](https://www.poison.org/first-aid-for-poisonings)

## Risks From Rain, Extension Cords, and Refueling

Generators pose risks of electric shock and fire in addition to CO. Moving a generator into a garage to protect it from rain is not permitted. Follow the manufacturer's instructions for use in severe weather.

| Item to check | Standard to apply |
|---|---|
| Ground and cover | A dry location where water does not pool or flow in, with a protective structure that allows open ventilation |
| Hands and connections | Do not operate with wet hands, and protect electrical connections from water |
| Extension cord capacity | An outdoor-rated product with a rating greater than the total power consumption of connected devices |
| Extension cord condition | Check for damaged insulation, missing grounding pins, and crushing in doorways |
| Extension cord length | Long enough to maintain the generator's safe distance and cover the actual wiring route |
| Refueling | Turn off the generator and allow it to cool sufficiently before refueling |
| Fuel storage | Use a suitable safety container outside living areas |

Fuel spilled on a hot engine can ignite. Do not arbitrarily set the cooling period to a few minutes. Check the product manual's refueling requirements. [CPSC Portable Generator Hazards](https://www.cpsc.gov/safety-education/safety-guides/carbon-monoxide/portable-generator-hazards)

Do not plug a generator into a wall outlet to send power into home wiring. This is called backfeeding. Electricity can flow into external power lines and electrocute workers. Connections to home wiring must use a suitable transfer device installed by a professional. [PSE generator safety guidance](https://www.pse.com/safety/electric-safety/generator-safety)

## Power Gaps During Refueling in Households With Medical Devices

Households with medical devices must also arrange power for periods when the generator is stopped. A generator must be stopped and allowed to cool before refueling. Therefore, securing generator fuel does not provide an uninterrupted power supply. This conclusion applies generator safety guidance together with FDA power outage planning.

FDA advises checking the backup power available for each device and the acceptable period of interrupted operation. Life-sustaining devices such as ventilators especially require individual plans. Do not determine whether a backup battery can be connected based only on its appearance. [FDA guide to power outage planning for home medical devices](https://www.fda.gov/downloads/MedicalDevices/ProductsandMedicalProcedures/HomeHealthandConsumer/UCM252812.pdf)

| Preparation item | What to confirm | Who to ask |
|---|---|---|
| Generator and extension cord | Whether the device may be connected and the required power conditions | Manufacturer or supplier |
| Backup battery | Compatibility, operating time, and power switching method | Manufacturer or supplier |
| Refueling and cooling | Alternative power to use while the generator is stopped | Supplier or medical team |
| Treatment interruption | Whether interruption is permitted and how to resume treatment | Medical team |
| Evacuation | Destination where the device can be used and means of transportation | Local emergency management agency or medical team |

Battery operating time must be confirmed under the conditions of the specific device. Do not assume operating time based only on an unverified capacity. If a power gap cannot be tolerated, an advance evacuation plan is needed.

FDA recommends informing the power company and fire department that medical devices are in use. Emergency assistance is needed if power for a life-sustaining device cannot be secured. After power is restored, check whether the device settings have changed. [FDA medical device disaster preparedness guidance](https://www.fda.gov/medical-devices/emergency-situations-medical-devices/fda-offers-tips-about-medical-devices-and-natural-disasters)

## Common Mistakes

It is incorrect to treat one safety measure as a substitute for another condition. Distance, alarms, and refueling rules each reduce different risks. The following distinctions apply guidance from several agencies together.

| Common interpretation | Correction |
|---|---|
| The generator is 20 feet away, so exhaust direction does not matter | Exhaust must face away from building openings |
| The extension cord is 20 feet long, so the separation distance is sufficient | The actual placement distance and the route indoors are different |
| A CO automatic shutoff feature allows use in a garage | Automatic shutoff does not change the prohibition on indoor use |
| The alarm is silent, so the symptoms are not caused by CO | Suspected symptoms alone require evacuation and evaluation |
| The generator is off, so it is safe to go inside immediately | CO that has already accumulated may remain after shutdown |
| A generator means power to medical devices will remain continuous | Power gaps remain during refueling, equipment failure, and evacuation |

## The 2026 Hurricane Season and Document Dates

September 2026 falls within the official Atlantic hurricane season. The official season described by NHC runs from June 1 through November 30. This schedule does not indicate the current risk level for a specific area. Check the latest forecasts and alerts for local risk. [NHC tropical cyclone climatology guidance](https://www.nhc.noaa.gov/climo/)

The expert review date for the CDC generator guidance page is August 21, 2026. The review date for the power outage response page is August 26, 2026. A review date must not be interpreted as the date a new safe-distance standard was established. [CDC generator guidance page](https://www.cdc.gov/carbon-monoxide/factsheets/generator-safety-fact-sheet.html)

## Frequently Asked Questions

### Can 20 Feet Be Treated as 6m?

The exact conversion is 6.096m. Securing exactly 6m falls short of 20 feet. It is appropriate to allow extra distance when measuring.

### How Is NIST's 25 Feet Different From 20 Feet?

NIST recommends at least 25 feet from the home. This is farther than the 20 feet recommended by CDC and CPSC. Neither distance eliminates requirements for exhaust direction and alarms.

### Is an Apartment Balcony Acceptable Because It Is Outdoors?

EPA identifies balconies as prohibited locations for generator use. Being an open space alone does not make a location suitable. If safe placement is impossible, another power source or evacuation location is needed.

### If the Alarm Sounds but I Feel Fine, Can I Wait?

Evacuate outdoors immediately even if you have no symptoms. CPSC advises calling 911 after evacuating. Waiting until symptoms appear is not appropriate.

### Should I Contact 911 or Poison Control First?

In the United States, call 911 first for a CO alarm or emergency symptoms. Decreased consciousness, difficulty breathing, and seizures require an immediate call. For other exposure consultations, call 1-800-222-1222 after evacuating.

### Do Battery Power Devices Also Emit CO?

Battery power devices that do not burn fuel do not produce combustion exhaust. EPA identifies battery devices as an alternative power source for small devices. The manufacturer must confirm whether a medical device can be connected. [EPA guidance on power outages and indoor air](https://www.epa.gov/emergencies-iaq/emergencies-and-indoor-air-quality-iaq)

### How Many Hours of Battery Power Should Be Prepared for a Medical Device?

There is no single duration that applies to every device. The FDA guide advises checking the battery operating time for each device. Power during evacuation and the acceptable duration of treatment interruption must also be included in the individual plan.

## FAQ

### For a portable generator, how many meters is 20 feet?
20 feet is exactly 6.096 m. A distance of exactly 6 m falls short of 20 feet.

### Why does NIST advise 25 feet?
NIST's generator safety guidance recommends at least 25 feet from a home. This is farther than the 20 feet recommended by CDC and CPSC. In addition to distance, the direction of the exhaust must also be checked.

### Can a generator be used if the garage door is open?
It cannot be used even if the garage door is open. This is because CO can build up in a partially enclosed space. A fan or open window also does not make indoor use acceptable.

### Can a generator be used on an apartment balcony?
EPA advises that generators must not be used on balconies. If there is no outdoor location where a safe distance can be maintained, consider another power source or a place to evacuate to.

### Where should CO alarms be installed?
CPSC recommends installing them on every level of the home and outside sleeping areas. Battery-powered alarms or alarms with battery backup that work during a power outage are needed. Follow the product manual for specific placement.

### Is a CO alarm unnecessary if the generator has an automatic CO shutoff feature?
A separate indoor CO alarm is still needed. The generator's automatic shutoff feature also does not replace outdoor placement and distance requirements.

### Can I wait if the CO alarm sounds but I have no symptoms?
Even without symptoms, evacuate outdoors immediately. In the United States, call 911 from a safe outdoor location.

### What are the main symptoms of carbon monoxide poisoning?
Symptoms may include headache, dizziness, weakness, nausea, vomiting, chest pain, and confusion. If several people become ill at the same time, common exposure should be suspected. Poisoning cannot be confirmed or ruled out based on symptoms alone.

### What is the phone number for a U.S. poison control center?
The number for reaching a U.S. poison control center is 1-800-222-1222. For advice about CO exposure, first move to a safe outdoor location. If there is reduced consciousness, difficulty breathing, or seizures, call 911 immediately.

### Can a generator be refueled while it is running?
Do not refuel it while it is running. Turn off the generator and let it cool sufficiently before refueling. Fuel spilled on a hot engine can catch fire.

### Can connecting a generator to a wall outlet supply electricity to the entire house?
Do not feed generator power through a wall outlet. Backfeeding can electrocute workers outside. Connecting it to home wiring requires a suitable transfer device installed by a professional.

### How should the runtime of a backup battery for a medical device be determined?
Check the operating time with the device's manufacturer or supplier. Confirm with the healthcare provider whether treatment can be interrupted. The plan must also account for gaps in power during refueling, cooling, and evacuation.

### Once power to a medical device returns after an outage, can it immediately be used as normal?
The FDA advises checking the device settings after power is restored, as a power outage may cause them to revert to the default settings. If anything is wrong, check with the supplier or a healthcare professional.

## Sources

- [CDC, What to Do to Protect Yourself During a Power Outage, reviewed August 26, 2026](https://cdc.gov/natural-disasters/response/what-to-do-protect-yourself-during-a-power-outage.html)
- [CDC, Generator Safety Fact Sheet, reviewed August 21, 2026](https://www.cdc.gov/carbon-monoxide/factsheets/generator-safety-fact-sheet.html)
- [CDC, When the Power Goes Out, Keep Your Generator Outside](https://www.cdc.gov/carbon-monoxide/media/pdfs/Generators_1.pdf)
- [CPSC, CPSC Warns of Generator, Carbon Monoxide and Fire Hazards Ahead of Hurricane Season, May 27, 2026](https://www.cpsc.gov/Newsroom/News-Releases/2026/CPSC-Warns-of-Generator-Carbon-Monoxide-and-Fire-Hazards-Ahead-of-Hurricane-Season)
- [CPSC, Portable Generator Hazards and Connection Safety Guide](https://www.cpsc.gov/safety-education/safety-guides/carbon-monoxide/portable-generator-hazards)
- [EPA, Where to Safely Use a Fuel-Powered Portable Generator Infographic](https://www.epa.gov/emergencies-iaq/where-safely-use-fuel-powered-portable-generator-infographic)
- [EPA, Emergencies and Indoor Air Quality](https://www.epa.gov/emergencies-iaq/emergencies-and-indoor-air-quality-iaq)
- [NIST, Generator Safety](https://www.nist.gov/social-media/generator-safety)
- [Poison Control, Carbon monoxide: What you need to know](https://www.poison.org/articles/carbon-monoxide)
- [Poison Control, First aid: Act fast!](https://www.poison.org/first-aid-for-poisonings)
- [FDA, FDA Offers Tips about Medical Devices and Natural Disasters](https://www.fda.gov/medical-devices/emergency-situations-medical-devices/fda-offers-tips-about-medical-devices-and-natural-disasters)
- [FDA, Home Use Devices: How to Prepare for and Handle Power Outages for Medical Devices that Require Electricity](https://www.fda.gov/downloads/MedicalDevices/ProductsandMedicalProcedures/HomeHealthandConsumer/UCM252812.pdf)
- [PSE, Generator Safety Tips and Information](https://www.pse.com/safety/electric-safety/generator-safety)
- [NHC, Tropical Cyclone Climatology](https://www.nhc.noaa.gov/climo/)

## Images

![Woman moving a wheeled portable generator across a backyard away from the house](https://injoys.com/rails/active_storage/blobs/proxy/eyJfcmFpbHMiOnsiZGF0YSI6MTk1MDYsInB1ciI6ImJsb2JfaWQifX0=--859aa3702b321a405e5bad33f8e438cc7e468ae6/ai-3b00a582.webp)
![Woman moving a portable generator across a lawn away from an open garage, with exhaust arrow](https://injoys.com/rails/active_storage/blobs/proxy/eyJfcmFpbHMiOnsiZGF0YSI6MTk1MTMsInB1ciI6ImJsb2JfaWQifX0=--02a5f56d1bd3732e55db02aa13f704ca7958f8af/ai-a14b2197.webp)