When does a City of Maricopa tenant improvement need a permit, and what plumbing plans go with it?

The City of Maricopa guide's Applicability section says: "A Tenant Improvement Building Permit is required under the following conditions." There are three:

1. 1"When any work is done to enlarge, alter, repair, improve, convert, or cause the same to be done to any building."
2. 2"When Electrical, Plumbing, Heating and Air Conditioning Systems are altered or expanded."
3. 3A change of occupancy.

Before the permit issues, a Zoning Permit approval is needed to verify zoning compliance. Construction plans must be prepared, sealed, signed and dated by an Arizona registered design professional, and the guide says a registered professional is required per A.R.S. 32-141 unless exempt per A.R.S. 32-144.

The plumbing plan requirement is the quote above, followed by eight items:

• Show all existing and proposed plumbing fixtures.
• If any fixtures are added, provide waste and water isometrics.
• Provide water and waste calculations for added fixtures so existing services are shown to be adequate for the additional load.
• For gas appliances, provide a gas isometric with PSI, distances, BTU, demands and pipe sizes.
• Show locations and capacities of all grease, sand or oil interceptors.
• Specify all piping materials.
• Show all backflow prevention devices.
• Specify expansion tanks for all water heaters.

The city's submittal list also asks for water and septic "Will Serve" letters where applicable, and its site plan must show the water meter curb box and sewer tap locations.

• Altered or expanded. The guide does not define it. Adding a fixture is the case it names: the isometric and load calculation items apply "if any fixtures are to be added."
• Isometric. In drafting use, a piping diagram drawn in three dimensions; the guide does not define it. The guide asks for waste and water isometrics when fixtures are added, and a gas isometric for gas appliances.
• Change of occupancy. The guide lists it as its own trigger. A shift from retail to restaurant is a common example; the guide does not give examples.

Anyone doing tenant improvement work in a commercial space within the City of Maricopa. All food service facilities also need separate approval by Pinal County, and fire sprinkler and fire alarm submittals need their own permits and approvals.

This does not apply to work in unincorporated Pinal or Maricopa County, where the county issues permits.

One caution on codes. The guide, revised 9/2025, says the codes used are "2018 IBC, IMC, IEC, IFC & 2017 NEC" and names no plumbing code. The city's Building Safety page says Maricopa has adopted the 2024 edition of the International Building Codes, including the International Plumbing Code, with an effective date of February 2, 2026. Maricopa City Code 15.05.080 (Ord. 26-01) adopts the 2024 IPC with amendments, including "Delete Section 114.4 in its entirety" and "Amend Section 403.2 by changing the number 15 in Exception 2 to 30 and deleting Exception 3." Design to the 2024 IPC with those amendments, and ask Development Services before you rely on the guide's code list.

A dental office in a vacant suite. The tenant adds three operatories with sinks. Fixtures are added, so the plan set needs waste and water isometrics and the load calculation, and every new device on the water side, including backflow devices, shown. The designer seals the plans.

A cafe taking over a retail space. There is no plumbing change planned, but occupancy changes from retail to food service, which is its own trigger for the permit. The city also reminds food service tenants to get separate Pinal County approval, and the plan set shows interceptor locations and capacities if one is involved.

The edge case. A tenant says the work is "just a remodel" with no plumbing. The guide's first trigger covers work to alter, repair or improve a building. Whether a given scope is exempt is not stated in the guide, so Development Services has to answer that.

1. 1Get Zoning Permit approval first through the Planning and Zoning Division at 520-316-6920 or DSD@maricopa-az.gov.
2. 2Have an Arizona registered design professional prepare and seal the plans.
3. 3Build the plumbing plan set from the list above, and add the water and septic "Will Serve" letters where they apply.
4. 4Apply through the city's VIP portal and pay fees from the Development Services fee schedule. The city's Rev 5/2026 turnaround chart lists Commercial Tenant review at 8 working days for a first review, 4 for later reviews, 20 for substantive review and 30 overall, and notes City Hall runs a four-day work week.
5. 5Name files as (Plan Type) - (Project Name) - (Submittal #), PDF only.
6. 6If the tenant is food service, start the Pinal County Environmental Health review in parallel.

• Myth: The plumber's drawing is the plan. The guide requires plans prepared, sealed, signed and dated by an Arizona registered design professional, unless exempt per A.R.S. 32-144.
• Myth: Zoning comes later. Zoning Permit approval is a prerequisite before the TI permit issues.
• Myth: The guide's code list tells me the plumbing code. It names no plumbing code. The city's page and City Code 15.05.080 name the 2024 IPC.
• Myth: A city permit covers the restaurant. The guide says all food service facilities require separate approval by Pinal County.