It's an affidavit a licensed plumber signs stating that gas piping at the meter passed a leakage test, with the test pressure, hours and date. Con Edison uses this form in New York. In the Phoenix area the same proof comes through a city permit, inspection and gas clearance before Southwest Gas turns gas on.
What the form is and who signs it
The best-known version comes from Con Edison, the utility for New York City and Westchester County. Its New York City affidavit begins: "This certifies that the gas meter piping installed between the service head valve and the meter connection" at the listed address "has successfully passed a leakage test for" a stated number of hours at a stated pressure in psig on a stated date. Con Edison's Westchester version reads almost the same, except it covers "the gas meter piping installed inside the building."
The fields on both are short:
- The address, lot, block and owner
- The test length in hours, the test pressure in psig, and the date
- The plumber's signature and license number, and the plumbing contractor
- A line where Con Edison signs, "Accepted for the Company By"
One detail matters. The New York City form carries a note at the top: "This Affidavit Does Not Replace A Blue Card." In other words, the plumber's sworn statement goes to the utility, and the city's own sign-off is still a separate step. That split between a plumber's test, the utility and the building department shows up in Arizona too, just with different paperwork.
How the same proof works in the Phoenix area
In Phoenix, the proof comes from the city. The City of Phoenix Planning & Development Department, Southwest Gas and the Arizona Corporation Commission "have developed a list of common repairs or alterations to an existing gas piping system in a residential or commercial application that require a City of Phoenix permit, inspection and a gas clearance." A few rows from that table:
| Work or condition | Permit | Inspection by | Clearance by |
|---|---|---|---|
| Any new gas piping installation | Yes | City | City |
| Alteration to an existing gas piping system, other than installing an appliance connector | Yes | City | City |
| Gas meter locked off by Southwest Gas for a leak on the customer side of the meter | Yes | City | City |
| Replacement in kind of any gas appliance with no gas piping alterations | No | Southwest Gas | Southwest Gas |
| Gas meter locked off by Southwest Gas for non-payment | No | Southwest Gas | Southwest Gas |
So for piping work, the plumber tests, the city inspector checks the work, and the city's gas clearance tells Southwest Gas the line is ready. Nothing in that table calls for a separate signed affidavit to the utility. If a utility, a lender or a building department ever asks you for a signed test form, ask them which form they want and who files it.
Southwest Gas has its own checks too. Its Arizona tariff says "The customer shall provide a leak tight system for receiving gas." It adds: "The Utility shall perform a leak check on the customer's piping system when the gas is turned on." The tariff defines that leak check as a pressure test of the customer piping system using natural gas at standard delivery pressure, or a higher pressure if the utility judges it necessary. And the tariff keeps a paper option open: "The Utility may also refuse service until a certificate executed by an authorized public official or licensed plumber is issued."
Other Valley cities run their own permit and clearance steps. Our page on getting gas turned on after inspection in each Valley city compares them.
What the pressure test itself has to show
Any form or clearance is only as good as the test behind it. Phoenix's residential code follows the 2024 International Residential Code. Section G2417.1 says that before gas is used, "all piping installations shall be visually inspected and pressure tested". The goal is to show the pipe and the work meet the code.
The numbers from the same section:
- Pressure. At least one and a half times the proposed maximum working pressure, and never less than 3 psig.
- Time. "The test duration shall be not less than 10 minutes."
- Test gas. "The test medium shall be air, nitrogen, carbon dioxide or an inert gas. Oxygen shall not be used as a test medium."
- Pass or fail. "Any reduction of test pressures as indicated by pressure gauges shall be deemed to indicate the presence of a leak unless such reduction can be readily attributed to some other cause."
Those are code floors, and some Valley cities set higher test pressures. See gas pressure test rules by city for the local numbers and how a gas line pressure test works for what happens on the gauge. Notice what a New York affidavit records: pressure, hours and date. Those are the same facts a city inspector looks at here.
When this comes up for a homeowner
Most people run into test paperwork at one of three moments:
- 1New gas service or a new line. A new meter or an added appliance line means new piping, so it's permit, test, inspection and clearance. Our guide to getting a gas line and meter to your house walks through the order.
- 2A red tag or locked meter. If Southwest Gas shut the meter for a leak on your side, Phoenix's table puts that repair under a city permit and clearance. See what a Southwest Gas red tag means.
- 3Buying or selling a home. Buyers sometimes ask for proof that gas work was permitted. The city or county permit record and the final inspection result are the documents to ask for. Our page on whether home inspectors check gas lines covers what an inspection does and doesn't look at.
Keep copies of the permit, the inspection result and the clearance with your house papers. They answer the same question a New York affidavit answers.
### Common mix-ups
A few terms get blurred together. Here's how they differ:
- Pressure test vs. leak check. The plumber's pressure test uses air or an inert gas at test pressure. Southwest Gas's leak check uses natural gas at delivery pressure when it turns the gas on. Both happen.
- Affidavit vs. clearance. An affidavit is the plumber's own signed word. A Phoenix gas clearance comes from the city after its inspector checks the work.
- Appliance swap vs. piping work. Replacing a water heater in kind with no pipe changes goes to Southwest Gas in Phoenix's table. Adding a line or changing pipe goes to the city.
- Red tag vs. lockoff for a bill. A leak lock on your side needs the permit path. A lockoff for non-payment goes back to Southwest Gas.
If you're unsure which path your job is on, the city permit desk can tell you.
Who should do the test
A licensed plumber, under a permit, with the city or county inspecting. Phoenix lets the owner-occupant of a single-family home pull their own permit, but the test gear and the stakes make this a job for a licensed plumber. Our page on who can install a gas line in Arizona covers the licensing rules.
HQ Plumbing & Air does gas line repair and installation under permit. You get a free estimate and an upfront price before any work, from a licensed and insured crew. If you smell gas at any point, Southwest Gas says: "If you smell rotten eggs, leave the area, then call us for help."