DENVER -- If there was an emergency in your neighborhood, how would you find out?

Many cities and counties have a reverse notification system, sometimes called reverse 911, that calls your home phone when there is a fire, flood or other emergency situation. But did you know in many places you can also sign up to get those notifications on your cell phone, e-mail and by text?

Arapahoe County said it will send messages about a potential safety hazard or concern to all standard voice and text communication devices (land line, mobile, e-mail, instant messaging, text messaging, PDA, alpha or numeric pager, etc.) that you register in the system.

Aurora has its own system that will send alerts to a mobile phone, by text message, by e-mail or all means.

Broomfield and Jefferson counties use the e911 system to send out emergency alerts.

Boulder County has a mass notification system that is used to notify residents about imminent threats to health and safety such as the need to evacuate due to a wildfire, or take other appropriate actions in the event of a flash flood or other critical police activity.

Denver & Denver County lets residents register cell phones and VoIP with its 911 emergency notification system.

Douglas County uses the Everbridge Aware mass notification system to alert residents about fires, floods, toxic environmental issues and other emergencies. Officials said messages can be sent to residents on any communication path desired – cell phone, home phone, email, text messaging, pager, PDA and more.

In Larimer County, visit the subscription services page. Click on "Emergency Information Updates." You may also want to sign up with the Larimer Emergency Telephone Authority for emergency alerts.

Weld County will let you sign up for several different alerts including a list of most wanted fugitives, recent arrests and EOC alerts. Signing up for the EOC alerts will get you updates when emergency and disasters are happening.

Adams County officials told 7NEWS they do not have a system yet to call cell phones in an emergency.

If you live within city limits, you should sign up with your county and contact your local city to ask how you can register your cell phone for emergency alerts/calls.