The biggest challenge in moving through the pilot process here in Arizona was meeting the concerns of public health officials. A number of meetings, presentations, and even a few system tweaks were needed to keep the process moving forward positively. We were very thankful for the insight of our technical advisory committee that helped to provide direction.
There is a group in Oregon called ReCode Oregon also moving through a number of sustainable code issues including composting toilets.
Also, David Omick (omick.net) a technical advisory member for us is also helping to revise national standards regarding composting toilets.
Overall the movement seems to be picking up momentum as the issue is popularized and the hidden away systems that have been used for years are finally feeling confident to be more forward about their use.