Compost from toilets should undergo fecal coliform and moisture content testing to ensure safety, the same biological testing that NSF-certified manufactured composting toilets must undergo. Testing depends on the lab, but usually costs between $35-70. Oregon State provides a useful list of soil testing facilities that serve Oregon. If the lab conducts fecal coliform testing for water they can also do it for compost. Most labs can also do a moisture test. Instead of a lab test one can also squeeze the compost to see if moisture beads up. If the compost is dripping wet, it’s too wet. If a bit of moisture beads up when it’s squeezed it probably has less than 40% moisture.