3.4 System Testing & Inspection Requirements

3.4 System Testing & Inspection Requirements

Core Principle: The TSBPE examination review course lists "required types and methods of testing and inspection of the plumbing system" as one of the subjects to master in the General Regulations chapter. Testing is also where the Plumbing License Law bites hardest: Board Rule 367.5(c)(1) makes the Responsible Master Plumber personally responsible for ensuring inspections are requested, and covering work before it is inspected is a violation whether or not the pipe leaks.

---

1. The General Rule

New, altered, extended, or repaired piping must be tested to disclose leaks and defects, and the test is conducted by the permit holder in the presence of the code official. Piping stays exposed — not backfilled, not covered, not concealed in framing — until the test is complete and accepted. Equipment, material, and labor for the test are furnished by the permit holder.

---

2. Drainage and Vent System Tests

How the water test is actually run. Plug the building drain at the base and fill the system with water to the highest opening. On a tall building the whole system may be tested at once or in sections, but where sections are tested, at least the upper 10 feet of the preceding section is included so that no joint is ever proved at less than a 10-foot head. Ten feet of head is only 4.33 psi — but that head, applied at the bottom of a five-story stack, is many times higher, which is why the base plug is the failure point (see the thrust-force calculations in Chapter 11).

[!NOTE] Air test caution. Never substitute oxygen, and never assume an air test is interchangeable with the water test where the AHJ has specified water. A 5 psi air test finds a leak but does not verify that the piping will hold a real hydraulic column.

---

3. Building Sewer Tests

---

4. Water Supply and Distribution Tests

Upon completion of a section or of the entire hot and cold water supply system, the piping is tested and proved tight under a water pressure not less than the working pressure of the system. Where water is impractical, air at 50 psi is the accepted substitute. The system must hold without leakage — the common practical standard is 15 minutes with no measurable drop.

Remember the distinction that trips candidates up:

• DWV = gravity system, tested with a head of water (10 ft) or 5 psi air.
• Water distribution = pressure system, tested at working pressure or 50 psi air.
• Fuel gas = tested at not less than 1.5 times the maximum working pressure but never less than 3 psig (covered in Chapter 9). Three different numbers, three different systems.

---

5. Component and Assembly Tests

---

6. The Texas Inspection Sequence

+---------------------------------------------------------------------------+
|   1. UNDERGROUND / GROUNDWORKS  -- under-slab DWV and water service        |
|      inspected and tested BEFORE any backfill or concrete pour.            |
|                              |                                            |
|                              v                                            |
|   2. ROUGH-IN / TOP-OUT      -- DWV, vent, water, and gas piping in the    |
|      framing, on test, BEFORE insulation or drywall.                       |
|                              |                                            |
|                              v                                            |
|   3. FINAL                   -- fixtures set, traps filled, final DWV air  |
|      test at 1 in w.c., water heater and gas appliances connected,         |
|      backflow assemblies tested and reported.                              |
+---------------------------------------------------------------------------+

Who does what in Texas:

• The RMP of record must ensure permits are obtained and inspections are requested in accordance with all applicable plumbing codes (Board Rule 367.5(c)(1)). Delegating the call does not shift the responsibility.
• Plumbing installed under an adopted code must be inspected by a licensed Plumbing Inspector, and the political subdivision may contract that inspection out only to a business that uses a licensed inspector, paid directly by the subdivision (Texas Occupations Code 1301.255(e), Board Rule 367.4(c)).
• Each plumbing inspector shall enforce the chapter (Section 1301.503). The inspector's license number goes on every green tag or correction notice.
• Municipalities of more than 5,000 inhabitants must regulate plumbing material, construction, alteration, and inspection by ordinance and require permits, though repairing leaks and replacing faucets, ballcocks, garbage disposals, and water closets are exempted from the permit requirement by statute.

---

7. Field Practices That Prevent a Failed Test

1. Cap every opening before filling. A missed test cap on a second-floor lavatory arm turns a water test into a drywall claim.
2. Let solvent-cemented joints cure. Below 40°F cure times lengthen dramatically; pressurizing green PVC is the most common self-inflicted failure.
3. Use the right gauge. A 0-to-200 psi gauge cannot resolve a 3 psi gas test or a 5 psi air test. Match gauge range and increment to the test pressure.
4. Watch the temperature. Air trapped in a system on a hot afternoon rises in pressure; a gauge that climbs and then falls as the sun moves is temperature, not a leak — but the inspector still needs a steady reading.
5. Never conceal before sign-off. Backfilled or covered work that has not been inspected can be ordered uncovered at the contractor's expense and is a documented code violation under Section 1301.452(7).