Section 1427 - Liability for tax1. The real estate transfer tax shall be paid by the grantor. If the grantor has failed to pay the tax imposed pursuant to this article or if the grantor is exempt from such tax, the grantee shall have the duty to pay the tax. Where the grantee has the duty to pay the tax because the grantor has failed to pay, such tax shall be the joint and several liability of the grantor and the grantee.2. For the purpose of the proper administration of this article and to prevent evasion of the tax hereby authorized, it shall be presumed that all conveyances are taxable. Where the consideration includes property other than money, it shall be presumed that the consideration is the fair market value of the real property or interest therein. These presumptions shall prevail until the contrary is proven, and the burden of proving the contrary shall be on the person liable for payment of the tax.