A.R.S. 9-807: Arizona Cities Cannot Force Fire Sprinklers on Your New Home

Most Arizona cities cannot make you put fire sprinklers in a new custom home. A.R.S. 9-807 is the reason. It takes the sprinkler decision away from city hall on any single-family house or small duplex and hands it to the owner, with one narrow exception for old ordinances that predate the rule. Here is what the statute blocks, what it still allows, and why one Valley town is different from its neighbors.

What the statute blocks

A.R.S. 9-807 speaks to cities and towns, not to you. It says a municipality cannot pass a code or rule that forces the sprinkler question one way or the other on a small home.

A municipality shall not adopt a code or ordinance ... that prohibits a person or entity from choosing to install or equip or not install or equip fire sprinklers in a single family detached residence or any residential building that contains not more than two dwelling units.

The protection covers the two housing types most custom-home clients build: a detached single-family house, and a building with no more than two units, such as a duplex or a main house with an attached second unit. The city also cannot charge a fine, a penalty, or tack on another requirement because of how you answer. Sprinklers stay an option you can add for safety or insurance reasons. They are not a line the city gets to force onto your plans.

The one exception: pre-2009 ordinances

The ban is not retroactive. A city that already required home sprinklers before the state stepped in gets to keep that rule.

This section does not apply to any code or ordinance that requires fire sprinklers in a residence and that was adopted before December 31, 2009.

That single date decides everything. A sprinkler mandate a town put on the books on or after December 31, 2009 is void under this section. One adopted before that date is grandfathered and still enforced. The statute sets no fire-flow, lot-size, or water-pressure trigger that would let a city bring back a mandate through a side door. If the local ordinance is newer than the cutoff, the city cannot require sprinklers on your house, and that is the end of it.

What this means for you

Whether your new home needs sprinklers comes down to one question: did your city grandfather a pre-2009 rule? Across most of the Jematell service area the answer is no. Scottsdale, Phoenix, Cave Creek, and Carefree cannot force sprinklers on a new single-family house, so that system is your call.

Fountain Hills is the standout. The town adopted its residential sprinkler requirement in April 2008, before the December 31, 2009 line, so 9-807 lets it keep the mandate. Build inside Fountain Hills town limits and your house needs an engineered sprinkler system covering every level plus the garage, which can add roughly 2 to 5 dollars per square foot to the job. Suppose a client prices one 4,000 square foot plan on two lots a few miles apart. On the Fountain Hills lot, the sprinkler system adds somewhere between $8,000 and $20,000 at that rate. On the Scottsdale lot, the same plan carries no sprinkler line at all, because Scottsdale has no grandfathered ordinance to enforce. Our page on Fountain Hills fire sprinkler requirements walks through the cost and the coverage.

One more practical point from the statute: a city has to accept the sprinkler permit application in print or electronic form, and it has to print the choice language from the statute on that application, so the option is spelled out where you sign.

How this connects to the rest of the law

9-807 is the sprinkler-specific limit on a city's broader power to write building rules. A city gets that power by adopting model codes under A.R.S. 9-802, and 9-807 carves the sprinkler mandate out of what those adopted codes can force on a small home. The county twin of this protection sits in A.R.S. 11-861 for unincorporated land. The town that enforces or waives the rule is your authority having jurisdiction (AHJ), and its fire rules ride on the International Fire Code. For the applied version, see do I need fire sprinklers in a new home in Fountain Hills and what building codes apply in Fountain Hills.

Full text and source

Read the current section, including the permit-format language, on the legislature's site: View A.R.S. 9-807 on azleg.gov. FindLaw mirrors the same text at codes.findlaw.com.

Because the whole rule turns on that 2009 cutoff, confirm your specific town carries no grandfathered sprinkler ordinance before you decide to leave the system off your plans.