Source-of-income non-discrimination
in Washington state, #HB2578 just introduced would prohibit landlord discrimination based on source of income
http://app.leg.wa.gov/billsummary?BillNumber=2578&Year=2018.
see also recent thread with @DanImmergluck and a suggestion for how to help implement such source-of-income protection
https://twitter.com/YIMBYwiki/status/946977605844004865.