The contribution of a house to your net worth is its value minus your mortgage. Any (and every) house, whether paid off or not, can be listed as an asset. I don't see why you wouldn't list all assets (if a value is readily available), in any case. If you have no income, your combined assets must total at least 5 times the poverty wage. For any year in which you had no income tax return, you should include a written explanation.