These are tough questions, Kacie
Here's a link to Portland's Zoning Codes:
http://sustainableportland.org/bps/i...=34560&a=53295
On page 5 of 42 is a chart with the 6 residential classifications and prohibited activities.
It looks like Residential Zone RF permits conditional use.
Many non-hazardous screen chemicals are considered "drain safe" in normal use,
but can cause problems with septic tanks.
The product literature and MSDS will tell you what's "drain permissible".
I'm sad to hear you're losing your house.
We work with many garage printers out of their homes.
Much will come down to your landlord's attitude,
and any neighbor's considerations or dreaded HOA's.
;-)
Best of luck.
Finding out zoning laws, rules, areas? 
