The project
In this example, the owners of a large Villa Park lot are adding a gas fire pit near the back patio, well away from the meter. A licensed plumber sizes the line for the fire pit plus the existing house appliances, pulls a permit, calls 811 to mark utilities, and lays pipe approved for burial in a trench with a tracer wire. A riser brings the line up beside the fire pit, ending at a new shutoff valve.
Before anything is connected, the plumber caps the line and sets up a test gauge. The trench is still open.
The test
Illustrative example. Not a real job or customer.
The line is pressurized to the test pressure the plumber and inspector expect. Partway through the test period, the gauge needle has dropped.
- The plumber does not restore gas or connect the fire pit.
- Leak solution is applied to every accessible joint: the tie-in at the house, the transition fitting and the riser.
- Bubbles form at the threaded joint on the riser where it meets the new valve.
- The joint is taken apart, cleaned, resealed with approved thread sealant and reassembled.
- The full test is repeated from the beginning, and this time the gauge holds steady for the whole period.
The line passes, the inspector signs off with the trench open, and only then is gas introduced and the fire pit lit.
Why the failed test was good news
Caught during testing
- Leak found with the trench open and joints exposed
- Fixed with no gas in the line
- No hazard to the household
If the test had been skipped
- Gas would have leaked at the riser in use
- Leak might go unnoticed outdoors
- Finding it later could mean reopening finished work
What to expect on your own project
- The plumber tests before connecting appliances
- A failed test means more work, not a failed project
- The repeated test starts over from the beginning
- Trenches and walls stay open until testing and inspection are done
Questions to ask about testing
- Will you show me the gauge at the start and end of the test?
- Which joints are most likely to leak on this kind of run?
- Will the inspector see the test with the trench open?
Common questions
Did this happen at a real home?
No. It is a made-up example to illustrate pressure testing.
Does a failed test mean the plumber did poor work?
Not necessarily. Tests exist to find leaks before gas flows; what matters is that it is fixed and retested.
Can the fire pit be lit before the inspection?
Where a permit applies, gas should not be put into service until the work passes inspection.
General information for Villa Park, not a quote or professional advice. In an emergency, call 911.