Keep in mind that Arvada Fire is a "District" and that they are a separate entity from the City of Arvada. Their district covers areas outside the city limits and they are not under the direct control of the City of Arvada. When Westminster and Arvada joined together to buy their EDACS system the fire district was under no obligation to join in and they decided to stay with their conventional system.
Last that I knew, the fire district had gone paid. They did have one or two stations that were still volunteer, but the majority of the firefighters are now paid. Keep in mind that this is information I got a couple of years ago and that things may have changed since then. For all I know they could be 100% paid now!