I've received a few questions about Google Voice phone numbers lately. As is typical, there is not much documentation on this topic, although Google Voice's legal notices mention some scenarios.
Google Voice phone numbers that were obtained from Google's pool of free numbers will be reclaimed or suspended under these circumstances:
- If you have not placed at least one outbound call or sent one outbound text message within a nine month period. Inbound doesn't count, since an abandoned number could still be receiving calls or texts. The goal is to reclaim phone numbers that have been abandoned, so that other people can use them.
- You start with a free Google Voice number, and then you port in a mobile phone number. In this scenario, your free number changes to a pending-deletion mode, for 90 days. This is intended to allow people time to let their contacts know that their number has changed. Before the 90 day deadline, you can pay a $20 fee to keep the original number. If your original number was also ported in, then it is automatically permanent, and it is not subject to the 90-day deletion interval. Ported-in numbers are not subject to the nine-month timer.
- If you delete a Google account (Gmail or G Suite), everything on that account is lost forever: all saved email, all documents, all calendar information, all Google Voice numbers, all saved voicemail, text messages and call history, and all contacts. None of it is recoverable after 30 days. There is no recourse to recover a number in this scenario, even if it was ported in.
- You have violated some Google policy; for example: using the phone number for robocalling, a call center, spam, harassment, illegal activity (think prostitution or stalking), or other suspicious usage patterns. You have sent out mass text messages, sent many outbound texts with no replies, sent multiple people texts with URLs, and other texting or calling patterns that look like abuse. Under these scenarios, your access to the service may be temporarily or permanently suspended without warning. You will not be able to use Google Voice again on that account, and any Google Voice phone numbers will be lost forever, even if they were ported in. Don't think of Google Voice as a provider of free, unlimited-use VoIP trunks. If you simply need trunks, pay for them from a ITSP.
Don't confuse this topic with the disposition of
linked forwarding phone numbers. If calls are not forwarded to a linked number, or calls made from that number via the apps, for some undisclosed time period (I believe it's a year, but this isn't documented), you will receive a reminder email, asking you to either re-verify the number, or delete it. If you do nothing, the linked number will be deleted. The intent is that people often cancel service or otherwise abandon linked numbers, and forget that they were used for forwarding. Then, the number is re-issued to some other telephone customer, and they start getting your forwarded calls and texts. You are welcome to re-link a forwarding number if you miss the warning email. Do not leave canceled/abandoned numbers on your configuration; it is unnecessary and leads to someone else getting annoyed when they get your calls.
Bottom line: "Don't be evil", and use the service as intended, and you'll keep your number as long as you wish.
The information above is based on my observations of the service over the past decade, information I have been provided by Google, and by reading the official information below, which is the only direct, authoritative information supplied by Google.
Adding, deleting, changing, porting numbers: https://support.google.com/voice/#topic=1708124 (https://support.google.com/voice/#topic=1708124)
Google Voice Acceptable Use Policy: https://www.google.com/intl/en_US/googlevoice/program-policies.html (https://www.google.com/intl/en_US/googlevoice/program-policies.html)
Google Voice Additional Terms of Service: https://www.google.com/intl/en_US/googlevoice/legal-notices.html (https://www.google.com/intl/en_US/googlevoice/legal-notices.html)