I know it doesn't help the OP, but for me, it is required by law to have a landline.

Question, rather than worry about required or not, does it work in an emergency? If you called 911 on your cell phone, will they know where you are? Will the ambulance be able to get to you? Will your cell phone connect you to the proper 911 dispatch center? That is what is the most important, IMO.

Where I am, the 911 dispatchers, don't have a clue where anything or anyone is. This is true even with the landline, that has my address associated with it. I wouldn't trust just a cell phone, because I know, that even though I am a 4 minute drive from the hospital, they would still probably take 15-30 minutes to find me. That is if I get the right dispatch center. Depending on how the wind is blowing, literally, I could get dispatch from Ontario, and they don't have any way to connect me to the dispatch here. It is a mess.