What are the most common plumbing code violations?

• Not enough slope. The checklist says to "Maintain a minimum ¼" slope per foot of run for pipe sizes 2" and smaller" and an eighth of an inch per foot for pipe sized 3" to 6". The plumbing code's Table 704.1 sets the same figures: 1/4 inch per foot for pipe 2 1/2 inches or less and 1/8 inch per foot for 3 to 6 inches. Flat drains hold solids, so this one causes slow drains years later. See drain pipe slope under code.
• Cleanouts missing or buried. It calls for a "Cleanout for each 100' and direction changes >45 degrees," and at final to "Install all cleanout plugs and caps" and "Extend sewer pipe cleanouts to finish grade." Section 708.1.4 of the code puts a cleanout at any change of horizontal direction greater than 45 degrees. A cleanout under the dirt isn't a cleanout. More in cleanout code requirements.
• No backwater valve where one is needed. "Use a backwater valve when flood level of fixture is below the upper manhole rim."
• No tracer wire. The sewer piping from the cleanout at the building drain and building sewer connection "shall have a tracer wire (#18 gauge minimum) run with the piping to the sewer tap."
• No leak test. "Do a minimum 5' high water column pressure test on the drain/waste/vent system and leave on for the inspection." Showers get a liner test and the top-out stage a 10-foot water test.

• Vent too close to a cooler. "Terminate vent pipes at least 6" through the roof and at least 10' from air intakes, such as evaporative coolers." Evaporative coolers are everywhere on Phoenix roofs, which makes this a local favorite. Section 903.5 of the code adds that an open vent terminal can't sit directly beneath any door, openable window or other air intake opening, or within 10 feet horizontally of one unless it is 3 feet or more above the top of that opening.
• Unvented trap arms. "Each trap arm must be vented," and the allowable trap arm length can't be exceeded.
• S-traps. "S-traps are prohibited." The trap weir, the high point of the water seal, can't sit higher than the top of the opening at the vent. See how a P-trap connects to a vertical drain.
• Oversized wet vents. "Only 1 and 2 fixture unit fixtures may drain into the vent of another fixture."

• Piping strained or unprotected. "Piping shall not be subjected to undue stress," and it must be protected from nail damage in studs, rafters and joists and from corrosion where it passes through concrete and masonry. "Keep dissimilar metals from touching."
• Joints under the slab. The checklist says "No joints allowed under the slab" for water piping, and penetrations through the slab must be wrapped or sleeved.
• No full-way valve at the water heater. "Fullway valve required at inlet to water heater and to the dwelling unit." The code also expects shutoffs on fixtures, which the plumbing safety devices page covers.
• Repairs made in place. "Repairs to defective parts or connections must be made by replacing the part."

• Hose bibs without vacuum breakers. The checklist's final list says "Vacuum breakers on hose bibs." See hose bib vacuum breakers.
• Toilet clearance. "Minimum side clearance to center of toilet is 15"." Front clearance is covered in toilet clearance code.
• Sink outlets. "GFCI protect garage, outside, and sink receptacles" is on the same list. See GFCI protection near sinks.
• Water meter location. The meter "must be installed and not in driveway."

1. 1Read the checklist for your permit type before the work starts, not after the failure.
2. 2Leave every test (the water column, the top-out test) running when the inspector arrives. What a top-out inspection involves and the final inspection walk through each stage.
3. 3Don't cover anything that hasn't been inspected.

If you're remodeling and want a permitted job done right the first time, HQ is licensed and insured, with free estimates and upfront pricing, for residential plumbing. The Phoenix Planning and Development Department decides how the code applies to a specific job.