The Town of Nederland has adopted the 2018 ICC code suite (fire, building, residential, etc), with amendments.  See the Town website for full details: https://library.municode.com/co/nederland/codes/code_of_ordinances

In the unincorporated areas of our district (Ridge Rd, Eldora, etc,) we have adopted the 2018 International Fire Code.  Building codes are adopted by Boulder County for these areas.  These can be found here: https://www.bouldercounty.org/property-and-land/land-use/building/building-code-amendments/