The Phoenix FD Regional Dispatch Center dispatches for:
Phoenix (includes Paradise Valley and Laveen)
Glendale
Peoria
Sun City-Youngtown
El Mirage
Surprise
Sun City West-Wittmann (note: not spelled Whitman or Whitmann)
Tolleson
Avondale
Goodyear
Buckeye
Buckeye Valley
Tonopah
Harquahala Valley
Daisy Mountain (includes Desert Hills, Anthem, New River, Black Canyon City, and Cave Creek)
Scottsdale
Tempe
Guadalupe
Chandler
Sun Lakes
Maricopa (Town of, in Pinal County)
They also serve as the 9-1-1 Public Safety Answering Point for several others, although the call is then transferred to the other department/district for the actual dispatching, as I understand it.
Circle City-Morristown FD (between Wittmann and Wickenburg, at US 60/AZ 74, or Grand Ave & Carefree Highway) has its own repeater. I believe Rural-Metro handles their dispatching. I can hear it in Peoria, a mile west of Downtown Peoria.
Wickenburg FD has their own repeater, and self-dispatches, I believe. I've heard their repeater as far south as Bell Rd/Sun Valley Parkway in Surprise. You may not hear it much further south/southeast, though.
Luke AFB FD operates on the base trunked system. They sometimes respond off-base on mutual-aid incidents, and will then use either Phoenix or Rural-Metro channels.
Rural-Metro FD has two stations in the West Valley. Fire Stations 833 and 837. They're also in Carefree, Rio Verde Foothills, east Mesa, and San Tan Valley in Pinal County, southeast of Mesa Gateway Airport. Rural-Metro has their own channels.
Tonto Foothills is a small HOA-like community at the north end of the Carefree/Cave Creek area. They have their own small FD, with their own repeater.
Mesa FD Regional Dispatch Center dispatches for:
Mesa
Gilbert
Queen Creek
Superstition (Apache Junction, Gold Canyon, and surrounding area)
Rio Verde
Fountain Hills
Ft. McDowell (?)
Florence (in Pinal County)
The Salt River Community has it's own fire department, and they operate on their trunked system.
The Gila River Community has its own fire department and they operate on their trunked system.
That covers the entire Phoenix Metro area, and then some. There are some industrial fire brigades, such as Palo Verde NGS, McDonnell Douglas at Falcon Field in Mesa, the automotive test tracks (like Toyota in Wittmann) etc.
John
Peoria