The short answer to your question is: in your case, probably. However, for $6,700 the IRS would be unlikely to do that first; they'll look for other assets.
Basically, if the tax liability belongs to your mother (it was based on her income), then it became a lien on all of her property when it arose. Since you presumably didn't pay fair value for the house, and because you're a relative of your mother, the tax lien would still be attached to the house. So long as the tax lien is attached to the house the IRS can technically seize the house and sell it to pay for the taxes.
That being said, the IRS is very unlikely to seize a house and sell it just to recover $6,700 in taxes; certainly that won't be their first target. In your case, if you don't have the money to pay the tax they would encourage you to borrow $6,700 against the value of the house.
If you're the administrator of your mother's estate then you should call the contact number on the IRS notice and get more detail on what's going on. You will probably have to provide them with copies of your letters of administration before they'll discuss your mother's tax account with you. Find out what type of tax it is (e.g., income tax, estate tax, etc) and the year it's for. With that information you can decide if you want to just pay the tax and be done with it or you want to protest it. If you want to dispute the tax I would strongly recommend that you consult with a tax professional before you take any steps.
My answer does not constitute legal advice and may not be relied upon by anyone for any purpose and does not constitute an attorney/client relationship or an offer to form such a relationship. This disclaimer is intended to be fully compliant with the requirements of Treasury Department Circular 230 and the terms thereof are fully incorporated by reference. If you wish to consult with me please contact me at dwatchley@newyorktaxcounsel or visit my website at www.newyorktaxcounsel.com
You can be liable if you were responsible for her estate.
Estate Planning Lawyer
Tax Attorney Bellevue
Tax Attorney Everett
Tax Attorney Federal Way WA
Tax Attorney Bothell WA
Seattle IRS Contact
IRS Tax Problems Help
Late Filed Tax Returns
Estate Planning Attorney