2021 IPC Chapter 1
Chapter 1 of the 2021 International Plumbing Code (IPC) does not size a single pipe. It tells you who enforces the code, when a permit is needed, what gets inspected and when, and what happens when work goes wrong. Read it first, because every later lesson assumes you know how a job moves from permit to approval. It also comes with a local warning: the code this course teaches is a model code, and the jurisdiction where you work decides which plumbing code, and which edition, actually applies.
Texas does not hand every city the same plumbing code. Under Texas Occupations Code Section 1301.255, the State Board of Plumbing Examiners adopts the Uniform Plumbing Code (UPC) and the International Plumbing Code by rule and can adopt later editions, while cities may amend the adopted code to fit local concerns, as long as they do not substantially depart from state rules. Texas Municipal League guidance (July 2021) explains that a city puts building codes into effect by ordinance and, for plumbing, chooses either the UPC or the IPC. The state board's own rule has named the 2018 editions; a proposal published in the Texas Register on August 14, 2026 would move it to the 2021 editions, so check the board's current rule.
Houston chose the UPC. As of early January 2024, Houston enforces the 2021 Uniform Plumbing Code with local amendments, replacing the 2015 edition; the city has used the Uniform codes since 1985 (Houston Permitting Center, IAPMO announcement of October 26, 2023, Green Builder Media, November 20, 2023). Many other Texas cities use the IPC. This course teaches the 2021 IPC as the model. The principles carry over to Houston (permits, staged inspections, pressure tests, traps, vents, slope), but section numbers, some numbers and some fixture counts do not. The field rule: find the project's jurisdiction, ask the local code department which code, edition and amendments apply, and do that before you price or review anything. This course does not teach UPC section numbers.
Section 101.2 applies the code to the installation, alteration, repair, relocation, replacement, addition, use and maintenance of plumbing systems. Two handoffs matter in the field. Fuel gas piping, gas-fired water heaters and their venting belong to the International Fuel Gas Code. And appendices apply only where the jurisdiction has specifically adopted them. Detached one- and two-family dwellings and townhouses up to three stories may follow the IPC or the International Residential Code.
Existing buildings get their own rules. A lawful existing system may keep operating in line with its original design if it creates no hazard (102.2). Additions, alterations and repairs meet the requirements for new work, but the whole existing system need not be brought up to the code, as long as the work does not make it unsafe, unsanitary or overloaded (102.4). A change of occupancy that triggers special provisions needs the code official's approval (102.5), a real issue when a retail shop becomes a restaurant. Structural or building work in an alteration follows the International Existing Building Code (102.2.1), and the plumbing code never cancels local, state or federal law (102.10).
Section 106.1 requires a permit before anyone constructs, alters, repairs, moves or demolishes a building, changes its occupancy, or installs, alters, repairs, removes, converts or replaces any plumbing system. The exemptions in 106.2 are narrow: stopping leaks in pipe, clearing stoppages, repairing leaks in pipes, valves or fixtures, and removing and reinstalling water closets, all provided no valves, pipes or fixtures are replaced or rearranged. Replacing a defective concealed pipe with new material is new work and needs a permit and an inspection. An exemption never authorizes a violation. A facility that regularly employs qualified tradespersons may get an annual permit for alterations to an approved system, keeping a detailed record (106.1.1). Starting before the permit is issued can bring an extra fee (109.3).
An application goes on the jurisdiction's form with the fee, describes the work and its location, states the proposed occupancy, and is signed by the owner or agent (106.3). Construction documents go in with it, drawn to scale and clear enough to show the location, nature and extent of the work (110.1). A registered design professional prepares them where state law requires, and on buildings more than two stories tall they show where pipes penetrate and how fire-resistance ratings, fireblocking and structural safety are kept. The code official may waive plans for simple work.
Approved plans are stamped and followed, and changes need the code official's authorization (106.5.1). A permit may be issued for part of a system before all plans are approved, but the holder proceeds at their own risk. One approved set stays on site, and the jurisdiction keeps one for at least 180 days after completion (110.2). The permit or a copy stays posted on site until the project is done (106.5.7). A permit can be revoked if it was issued in error or on incomplete information (106.5.5).
Three 180-day clocks run in Section 106. An application is treated as abandoned 180 days after filing unless pursued or a permit is issued (106.3.2). A permit is null and void if work does not start within 180 days of issue, or if started work stops for 180 days (106.5.3). Before work resumes, a new permit is needed, at one-half the fee if plans are unchanged and the lapse has not exceeded one year. An unexpired permit may get one extension of up to 180 days at one-half the fee (106.5.4).
Worked example: a permit for a community center restroom remodel is issued March 2 at a fee of $640. The crew starts March 20 and stops April 10 when funding runs out. Counting 180 days from April 10 gives October 7, when the permit is null and void. If the owner returns by April 10 of the next year with unchanged plans, the new permit costs half: $640 divided by 2 is $320. After a longer gap, or with changed plans, the full fee applies and the plans are reviewed again.
Work must stay visible and accessible until approved, and the permit applicant must keep it that way; the jurisdiction does not pay to open or replace material for inspection (108.1). The permit holder schedules the inspections and notifies the code official when work is ready (108.2, 108.2.2). The IPC names three. Underground comes after trenches are excavated and bedded and the pipe is installed, and before backfill. Rough-in comes after the roof, framing, fireblocking, firestopping, draftstopping and bracing are in place and all piping is roughed in, and before wall or ceiling membranes. Final comes after the building is complete, fixtures are set and connected, and the structure is ready for occupancy. Work does not go past an inspection point without approval, and a failed portion stays uncovered until the code official authorizes it (108.2.3). Alternative engineered designs also need periodic special inspections and a written report from the registered design professional (108.3).
In the field
A church fellowship hall renovation is described as "just swapping two lavatories," but the plans also move a floor sink 6 feet to a new kitchen wall. Check Section 106.2 before you accept the "no permit" label. Fixture removal and reinstallation is exempt only when no pipes, valves or fixtures are replaced or rearranged, and moving the sink means new drain and vent piping. It needs a permit, and the rough-in must be inspected before the wall is closed. If drywall goes up first, the inspector can require it opened, and under 108.1 that cost is the permit holder's.
Section 108.4 sends plumbing work to the tests in Section 312. The permit holder makes them, the code official observes, and the permit holder furnishes the equipment, material and labor (108.4.2). Testing is not required where the work adds, replaces, alters or relocates no water supply, drainage or vent piping (108.4.1), and failed work is corrected and resubmitted (108.4.3). After tests and inspections show compliance, the code official issues a notice of approval, and can revoke it in writing if it was issued in error (111.1, 111.1.1). No one connects a permitted building to a utility, water system or sewer until the code official authorizes it (112.1), though a temporary connection for testing can be authorized (112.2).
Where strict compliance is impractical, the code official may grant a modification if health, life and fire safety are not lessened (105.1). Alternative materials and methods are approved when not less than equivalent to the code, and a denial is answered in writing with reasons (105.2). A stop work order is written, goes to the owner, agent or person doing the work, and states the reason and conditions for resuming (113.2); emergencies need no prior written notice (113.3). A board of appeals hears claims that the code was misread, does not fully apply, or that an equivalent is proposed, but it cannot waive code requirements (114.2). Penalty amounts in Section 115 are blank in the model code, so the local ordinance sets them.
1. A GCHS estimator is pricing a new office building inside the City of Houston. As of early 2024, which plumbing code does Houston enforce, with local amendments?
2. Under Texas Occupations Code Section 1301.255, what may a city do with the plumbing code the state board has adopted?
3. Which set names the three inspections listed in IPC Section 108.2?
4. A plumber has laid a 6-inch sanitary drain in a trench for a small clinic, bedded it on sand, and wants to backfill. Under Section 108.2, what must happen first?
5. An inspector arrives to rough-in a fourth-floor restroom in a Group B building and finds drywall already covering a drain stack. Under Section 108.1, who bears the cost of opening the wall?
6. Which of these jobs needs a permit under Section 106.2 rather than being exempt?
7. A permit is issued for a commercial tenant finish, but no work starts for 190 days. What is the status of the permit under Section 106.5.3?
8. A permit fee was $900. Work starts, then stops for 200 days. The owner returns within a year with unchanged plans. What is the new-permit fee under Section 106.5.3?
9. A plumbing contractor digs and roughs in a small commercial job before the permit is issued. What can Section 109.3 add?
10. Under Sections 108.2 and 108.2.2, who is responsible for requesting and scheduling the required inspections?
11. Who makes the tests required by Section 312 and furnishes the equipment, material and labor, according to Sections 108.4 and 108.4.2?
12. At an appeal hearing, a contractor asks the board of appeals to waive a required vent size because it would save cost. What does Section 114.2 say about the board's authority?
13. A new restaurant is finished and passed its final inspection. Under Section 111.1, what does the code official issue once tests and inspections show compliance?
14. A contractor wants the utility to connect a new commercial building to the public sewer before the final inspection so a crew can flush lines. What does Section 112.1 require?