Being able to send text messages to 911 would allow people who are deaf or have trouble hearing to communicate more easily with emergency responders.
The FCC proposed that providers "bounce back" texts in December.
In that proposal, it also suggested requiring wireless companies to let people send texts to 911 in all areas where 911 centers can accept the messages. The commission is still considering that idea, however the four largest mobile carriers have voluntarily agreed to provide the service by May 15, 2014.
In its rule, the FCC notes that the roll-out of the text-to-911 service "is still in the very early stages and will not be uniform."
"At the same time, as text-to-911 becomes more widely available, it is likely to generate increased consumer expectations as to its availability, which makes it increasingly important for consumers to be made aware when it is not available in an emergency," the FCC adds.
Under the new rule, wireless providers must implement the "bounce back" system by the end of September.
Requiring notice of failed text messages to 911 is part of a series of regulations the FCC is issuing to make more mobile and television services accessible to people with disabilities.
In recent weeks the agency has also adopted rules requiring cellphone Internet browsers and TV emergency signals to be accessible to people who are blind.