How to Choose a Gas Piping Contractor
If you smell gas right now, stop reading. Leave the building immediately. Do not switch lights on or off, use a landline phone, start a car, or do anything else that could create a spark. Once you are outside and clear, call Puget Sound Energy at 1-888-225-5773 or 911. Do not go back in until someone tells you it is safe.
Gas work is the one area of residential plumbing where getting it wrong has consequences beyond cost. Undersized lines starve appliances. Bad joints leak. Improper venting puts combustion products into living space. None of these announce themselves clearly, which is exactly why who does the work matters more than what it costs.
By Ramin Shahbaziasl, Owner, Eastside Repipe & Plumbing · Last updated October 02, 2025
This guide covers what to check before hiring, what the work involves, and what the code actually requires in Washington.
What to Do About a Suspected Leak
Worth knowing before you need it.
Signs of a gas leak:
The rotten egg odor utilities add to natural gas
A hissing or whistling sound near a line or appliance
Dead or dying vegetation near a buried line
Dust or bubbles blowing from the ground
Physical symptoms such as headache, dizziness, or nausea that improve when you leave
What to do:
Leave immediately. Take everyone with you, including pets
Create no ignition source. No light switches, no phones inside, no appliances, no vehicle ignition, no garage door opener
Call from outside. PSE at 1-888-225-5773, or 911
Do not go back in until the utility or fire service clears it
The utility comes first, not a contractor. PSE responds to gas emergencies, and they also provide free safety checks on gas appliances if you have a non-urgent concern. Once the situation is made safe, a licensed contractor handles the repair.
On detectors: carbon monoxide detectors are essential, but they do not detect a natural gas leak. CO is produced by incomplete combustion; a gas leak is unburned gas. Different hazard, different device. Have both.
Check the Licence First
Washington requires plumbing and gas piping work to be performed by certified tradespeople employed by a licensed contractor. This is not paperwork. It determines whether the work can be permitted and inspected, whether your insurance treats a resulting claim as valid, and whether you have any recourse.
Verify it yourself through the state Department of Labor and Industries. It is free and takes about a minute. Check the license is active, the bond is in place, and insurance has not lapsed.
Anyone reluctant to give you a license number has told you what you need to know.
What the Code Actually Requires Here
Gas piping in Washington is governed by the Washington State Fuel Gas Code, which adopts the International Fuel Gas Code with state amendments under WAC 51-52. Local jurisdictions add their own amendments on top, so requirements vary somewhat between cities in the same county.
Practically, this means:
Permits are required for new gas lines, extensions, and most alterations
Inspection is required before the system is put into service
Pressure testing is mandatory, not optional
Material and sizing are prescribed, including load calculations for total appliance demand
A contractor who treats permits as discretionary is proposing that you carry the risk. Unpermitted gas work also tends to surface during a home sale, which is an expensive time to find out.
When You Need a Contractor
Adding or moving an appliance. A gas range, dryer, fireplace, outdoor grill, or heater all need a properly sized connection. Adding load to an existing system may mean the line feeding it is now undersized.
Upgrading an older system. Older homes on the Eastside frequently have gas lines sized for the appliances of their era. Adding a modern high-BTU range or a tankless water heater often exceeds what the existing pipe can deliver. Our tankless water heater guide covers why this catches people out.
Suspected damage. Corrosion, physical damage from landscaping or excavation, or a line that has been disturbed by settling.
Routine inspection. Annual for older systems, and worth doing before you add load.
Questions to Ask Before Hiring
Are you licensed, bonded, and insured? Then verify independently
Will you pull the permit, and is it in the quote?
How are you calculating pipe size? A real answer references total connected load, pipe length, and pressure drop
What material are you using, and why? Black steel, CSST, and copper all have applications and constraints
How will you test the system? Pressure testing should be a given
What is your workmanship warranty, in writing?
Who inspects it, and when?
A quote well below the others usually excludes the permit, the testing, or both. Get three quotes and compare scope rather than the headline number.
What Installation Involves
Load calculation and design. Total demand across all appliances determines pipe sizing. This is the step that gets skipped and causes problems later
Permit application to the local jurisdiction
Material selection. Black steel for most runs, CSST where flexibility is needed, copper where permitted locally
Installation. Cut, thread, join, support, and label per code
Pressure test. The system is pressurised and held to confirm integrity before gas is introduced
Inspection. Signed off by the jurisdiction
Appliance connection and commissioning
Signs Your Gas Piping Needs Attention
Visible rust or corrosion on exposed pipe
An unexplained increase in your gas bill
Appliances that underperform, particularly when several run at once, which often indicates undersizing
Yellow rather than blue burner flames, which can indicate incomplete combustion
Soot marks around an appliance
Any gas odor, however faint
The last one is an emergency. The rest warrant a scheduled inspection.
Warning Signs in a Contractor
No licence number offered, or reluctance to provide one
Any suggestion that a permit is unnecessary
A quote given without inspecting the existing system
No mention of pressure testing
No written workmanship warranty
Pressure to decide immediately
Cash only, or a large deposit before work begins
Maintenance
Annual inspection, and before adding any appliance load
Keep buried lines clear of deep-rooted planting and note their location before any digging
Watch your gas bill. A climb with no change in usage warrants a look
Keep the area around gas appliances clear, particularly venting
Test CO detectors monthly and replace them per manufacturer schedule
A whole home plumbing inspection covers gas appliance connections alongside the rest of the system.
Frequently Asked Questions
What should I do if I smell gas?
Leave immediately, create no ignition source, and call PSE at 1-888-225-5773 or 911 from outside. Do not attempt to locate the leak yourself and do not go back in until it has been cleared.
Do I need a permit for gas piping work?
For new lines, extensions, and most alterations, yes. Permitting and inspection are part of the Washington State Fuel Gas Code, and requirements vary slightly by jurisdiction.
Can I install a gas line myself?
No. It is permitted work requiring certified tradespeople, prescribed materials and sizing, pressure testing, and inspection. The failure modes are fire, explosion, and carbon monoxide.
Will a carbon monoxide detector alert me to a gas leak?
No. CO detectors sense carbon monoxide from incomplete combustion, not unburned natural gas. You need both a CO detector and, ideally, a natural gas detector.
How often should gas piping be inspected?
Annually for older systems, and any time you add or replace a gas appliance. A new appliance can push an existing line beyond its capacity.
Why do my gas appliances underperform when several run at once?
Usually undersized piping. The line delivers enough for one appliance but not for the combined load. A load calculation establishes whether the pipe needs upsizing.
Book a Gas Piping Assessment
If you are adding an appliance, upgrading an older system, or you have noticed corrosion or an unexplained bill increase, an inspection is the sensible starting point. We will assess the existing system, calculate what it can actually carry, and quote the work in writing, including permits and testing.
Book an assessment or call 425-331-2011. See our specialized plumbing services for the full scope of gas line work we handle.
We serve Bellevue, Kirkland, Redmond, Seattle, and the wider Eastside service area.
For gas emergencies, call PSE at 1-888-225-5773 or 911, not us. Get the leak made safe first.
