Registered domestic partners.  Pub 555. This publication is also for registered domestic partners who are domiciled in Nevada, Washington, or California. Registered domestic partners in Nevada, Washington, or California must generally follow state community property laws and report half the combined community income of the individual and his or her registered domestic partner. Registered domestic partners aren't married for federal tax purposes. They can use the single filing status or, if they qualify, the head of household filing status.