OK - how about this? Client takes out a 1st in 2002 for $360,000. Then in 2003, they take out a HELOC for $60,000 and use $18,450 on credit card debt and $39,550 to build a pool for their main home. In 2009, they refinance and take out $25,000 and use $16,000 on credit card debt and $9,000 to build a room. Just how are we supposed to split the non-qualifying debt from the qualifying debt in determining how much interest is qualifying for 2018? Are the payments first applied to non qualifying, to qualifying, or in a ratio? I'm sure everyone else's clients know EXACTLY how much equity they spent and how much was credit card debt and how much was home improvements. But mine do not. THIS IS AN IMPOSSIBLE CALCATION and Congress are a bunch of stupid $&^^%#% morons for even considering that this is calculable. The law should have applied to NEW HOME EQUITY  DEBT ONLY and mandated that the banks indicate how much of any future loan is qualifying debt and non-qualifying debt. Unless I receive clear and concise directions on how to calculate this, ALL THE DEBT will be qualified.  Heck, most clients won't even remember if they took equity out of a refinance or not. Has to be one of the most RIDICULOUS laws I've ever heard of.  Naturally, the IRS will disallow ALL THE INTEREST unless we can prove the calculation - and the calculation cannot be proven. It's a total setup.