The home owner's insurance does not cover the possessions of a renter.

It is possible that the owner's insurance company requires him to require tenants to get renter's insurance.

If anything happens to the house your son is renting a room in, a fire or a flood or a tree falling on the house or just about any natural disaster, your son's belongings could be destroyed. Renter's insurance will help with the cost of replacing everything, just as homeowner's insurance helps a home owner replace their belongings.

Even if your son is only renting one room, he most likely has a TV, a DVD player, a computer, an iPod or something similar, a cell phone, maybe a printer, speakers, clothing, sports gear, books or CDs or DVDs, furniture (unless he is renting the room furnished) and other stuff. How much would it cost to replace all that, if he lost everything all at once?

Also, many renter's policies cover liability--if your son leaves something lying on the stairs and someone trips over it and hurts themselves, renter's insurance will help pay the costs--just as home owner's insurance will help pay the costs if someone slips and falls on an icy walkway. Or if the renter accidentally sets fire to his room and causes damage in the rest of the building, the insurance will come in handy.

Basically, this landlord will only rent to people with renter's insurance. If your son wishes to live there, he has to get the insurance. He should factor the cost of the insurance into the cost of the rent and see if that is a cost he is willing to pay. So let's say the room rents at $350/month and renter's insurance is $25/month. So the real rent that he has to pay is $375/month. If that is more than he wants to pay, he should look for different housing options.

Every place I have rented, I've either had to prove that I have renter's insurance, or there's a clause in the lease that makes it very, very, very clear that the landlord is not responsible for any damage to my belongings and individual renter's insurance is highly recommended.

Renters insurance isn't a bad idea. We had it when we rented. There were two tenants that would occasionally leave their ovens on and go off to work. Gave us piece of mind in the event that another tenant did something that could hurt our belongings.

Here are a few questions I might ask the landlord:

Does the landlord have house insurance? Has he ever had to file a claim for damage (flooding?) to the basement? Perhaps he can't get coverage because of past claims.

Is this basement legal to rent?
Does your son have his own (locked) entrance? Is he keeping anything of real value here?

Here is an article that might give you more food for thought. If your son decides to buy insurance, I would suggest he make a list of his valuables along with pics/serial numbers/receipts for those things he would want compensation for. I ran into a guy at Walmart that did this for his two properties. He had one in Galveston, Texas and another up north. He took pics of the entire contents of both places, made two copies of each (CD's), and kept these at both locations. Said he didn't want to lose everything again like he did when Hurricane Ike hit Texas in 2008.

A link that might be useful:

www.balancepro.net/education/publications/rentersinsurance.html