How do I make sure my compost is safe for use in my garden?

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.