I was also doing research and found the ruling that Opus 17 refers to ... Voss vs Commissioner of Internal Revenue. It was in 2015 when limit was higher. But language on ownership still same in TCJA (just limit reduced). I am also not an attorney.
Unmarried taxpayers who co-own a residence can each deduct interest payments on home-acquisition and home-equity debt up to the $1.1 million limit in Sec. 163(h)(3), the Ninth Circuit Court of Appeals held on Friday, reversing a Tax Court decision (Voss, No. 12-73257 (9th Cir. 8/7/2015), rev’g Sophy, 138 T.C. 204 (2012)).
Ninth Circuit acknowledged that the statute is silent about how the debt limit applies when there are unmarried co-owners of property, but it rejected the Tax Court’s analysis nonetheless. It noted that if Congress wanted the debt limits to apply on a per-residence basis
Look up Voss vs Commissioner of Internal Revenue (2015 ruling) for more information. TCJA makes no changes, from what I read. I am also not an attorney.
