Can PEX, CPVC or PVC water pipe be exposed outside in Surprise?

Surprise added a new section, 605.25, to the 2024 International Plumbing Code. It has two sentences. The first: "Non-Metallic potable water pipes, fittings, and valves shall not be exposed in exterior outdoor locations." The second: "Components of the exterior exposed potable water system shall be only metallic materials, fittings, and valves as listed in IPC Tables 605.3, 605.4, 605.5, and 605.6." Those four tables are the code's lists of approved pipe and fitting materials, so the metal has to be one the tables name, such as copper or the other metals they list.

The City made a second change on the same theme in its mechanical code amendments. Section 307.2.2 lists the pipe an air conditioner's condensate drain may use, plastics included, and Surprise's version adds: "Nonmetallic piping shall not be installed in exposed locations." It also asks for rigid tubing.

• Nonmetallic. Plastic. On a water line that means PEX, CPVC, PVC and the other plastics in the code tables, plus plastic fittings and valves.
• Potable water. The drinking water supply, from the meter to the fixtures.
• Exposed in exterior outdoor locations. In the open outside: along an outside wall, across a roof, or rising out of the ground to a hose bib, a backflow assembly or a piece of equipment.
• Condensate disposal system. The drain that carries water away from an air conditioner's coil.

The International Plumbing Code is the code for buildings outside the house code: stores, offices, restaurants, schools, apartment buildings and other commercial work. The house code, the International Residential Code, covers detached one- and two-family homes and townhouses up to three stories, and Surprise's amendment to its scope also sends to it the duplexes, triplexes and fourplexes that state law, A.R.S. 9-462.13, keeps out of the commercial code.

Surprise's house code amendments change only one plumbing water section, P2905.3, on how far hot water may travel to a fixture. They add nothing about plastic pipe outdoors. So a single-family house in Surprise is not under 605.25, while a strip center, an office park or a large apartment complex is. The mechanical amendment follows the same line, since homes take their condensate rules from the house code.

A restaurant adds an ice machine line on the roof. The water line runs across the roof in full sun. Under 605.25 it is copper or another listed metal from the roof penetration to the equipment, with metal valves.

An apartment complex replaces a leaking outdoor riser. A plastic riser came up out of the ground to a hose bib on a building wall and cracked. The repair has to be metal above grade. A plastic coupling on the exposed part would not meet the rule.

A homeowner in a 2000s subdivision. The softener loop's PEX rises out of the slab and runs along the garage wall outside. The house code governs, and Surprise's house amendments make no outdoor plastic rule, so 605.25 does not apply. Sun still ages exposed plastic, so covering or replacing an exposed run is often worth doing anyway, as our FAQ on PEX and CPVC explains.

1. 1Walk the building and mark every water line, valve and fitting that sits in the open outside, on roofs, walls and risers.
2. 2Specify a listed metal from IPC Tables 605.3 to 605.6 for those runs on any building under the plumbing code.
3. 3Check condensate drains on exposed roofs and walls as well, under the mechanical amendment.
4. 4Show the materials on the plans when the job needs a permit, and apply through the City's Permits and Applications page.

For a commercial building in Surprise, HQ's commercial plumbing team works on supply lines, backflow assemblies and rooftop water lines. Our Surprise plumber page covers the City's water systems and other local rules.

### Does PEX plumbing need to be insulated?

On a building under 605.25, wrapping or insulating exposed PEX does not make it legal outside; the exposed run has to be metal. On a house, a sleeve, insulation or a cover that keeps the sun off an exposed run is good practice, because sunlight is what ages plastic pipe.

### Can you bury PEX water lines in the yard?

Buried pipe is not exposed, so the rule does not reach it. Cross-linked polyethylene is one of the materials the code's water service table lists, so PEX can run underground to a building when it is installed to the code and the maker's instructions.

### Can PEX pipe be connected to a water heater?

PEX can connect to a water heater in many installs, but the heater's instructions and the code limit how close plastic may come to the tank. Our FAQ on water heater connectors and PEX covers the details.

### Will PEX freeze?

Hard freezes are rare in Surprise, and summer sun and heat are the bigger risk to exposed pipe here. PEX also tends to stretch rather than split when water in it freezes, which rigid plastic and copper do not.

• "This is the national code." Section 605.25 is a Surprise addition, as it is in Phoenix and Tempe. Mesa has no such rule.
• "It applies to my house." Not under Surprise's house code amendments, which add no outdoor plastic pipe rule.
• "Only the pipe has to be metal." The text names pipe, fittings and valves.
• "Painted or wrapped plastic is fine outside." The amendment gives no exception for paint or wraps. Exposed outdoor parts are metal only.

The amendments document linked above holds both sections, IPC 605.25 and IMC 307.2.2. This page explains them, and the official text governs.