CSST Gas Line Rules Update Sparks Debate-are Homes Safer?
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Recent changes to CSST gas line rules have tightened bonding, grounding, and material-certification requirements, particularly for new construction and major renovations, in response to lightning-induced puncture risks and a patchwork of older code interpretations. Since roughly 2018, national fuel-gas and electrical codes have converged on clear mandates that all corrugated stainless steel tubing (CSST) must be bonded to the building's electrical grounding system, while several states and provinces have added explicit prohibitions on non-arc-resistant jacketed CSST in residential gas systems.
What changed in 2024-2026?
Between 2022 and 2025, fuel-gas code amendments in the United States and Canada began requiring that CSST used in residential, commercial, and industrial buildings be listed to ANSI LC 1/CSA 6.26, the standard for gas piping systems using corrugated stainless steel tubing. This standard spells out construction, pressure ratings (up to 30 psi maximum operating pressure), and installation rules, including minimum support spacing and the use of striker plates where exposed tubing is at risk of puncture.
- Explicit listing requirement that CSST must comply with ANSI LC 1/CSA 6.26 before use.
- New or amended bonding clauses requiring all CSST systems to be electrically continuous and bonded to the building's grounding system, unless the tubing is certified for lightning-strike protection.
- Stricter limits on where CSST may penetrate walls or masonry, mandating non-metallic sleeves and proper sealing of annular spaces to avoid abrasion and corrosion.
- Updated support-spacing tables, typically requiring supports every 4 feet for 3/8-inch tubing and up to 8 feet for larger diameters, to prevent sag and vibration-induced fatigue.
State and provincial tightening since 2022
Several U.S. states have moved beyond the baseline national codes to ban non-arc-resistant jacketed CSST in new gas piping, a change that took effect in Maryland on October 1, 2022, under the Flynn and Laird Act. That law prohibits non-arc-resistant jacketed CSST in new construction, in major renovations affecting more than 50% of floor area, or when adding a new gas line to an existing system. Similar policy-level guidance has circulated through regional building-code groups such as the North Central Texas Council of Governments, which urged local jurisdictions to adopt stricter CSST inspection protocols and bonding verification.
- States like Maryland codified that only arc-resistant or properly certified CSST may be used in residential gas piping, with enforcement dates tied to local building-permit cycles.
- Canadian jurisdictions implementing CSA B149.1 and B149.3 have reinforced that CSST must be bonded in accordance with CSA C22.1, unless the tubing is certified for lightning-strike protection.
- Some utilities have issued internal CSST bonding policies requiring that bond wires connect to customer piping near the meter and to the building's electrical grounding system, not to the gas company's equipment.
- Local building departments have begun adding CSST bonding checks to rough-in inspections, especially in regions with high lightning density such as the Southeast and Midwest.
Why bonding and grounding rules got stricter
Historical data from insurers and investigators show that un-bonded CSST can be vulnerable to lightning-induced arcs, which can burn pinholes in the thin tubing and create fire or explosion hazards. Studies and field reports since the 1990s estimate that roughly 500,000 new homes in the United States are built each year with CSST, and many early systems were installed before consistent bonding language appeared in national codes.
Lightning striking near a house can induce a voltage difference between the gas piping system and the building's electrical grounding system; without a low-resistance bond, current seeks a path that may puncture CSST walls. Modern rules now require that all CSST-based systems-whether powered or not-be bonded using at least 6 AWG copper wire connected to UL 467 listed clamps on rigid customer piping or brass fittings, not on the corrugated stainless portion itself.
Key dates and code milestones
Model code updates have phased in CSST-specific requirements over roughly three cycles.
| Year | Change | Impacted systems |
|---|---|---|
| 2006 | Manufacturers' instructions uniformly require direct bonding of yellow CSST in new installations. | New residential and commercial gas systems using CSST. |
| 2015-2018 | National Fuel Gas Code (IFGC/ICG) and electrical codes add explicit bonding clauses for CSST, distinguishing arc-resistant vs. non-arc-resistant jacketed tubing. | Residential and small-commercial gas systems nationwide. |
| 2022 | Maryland's Flynn and Laird Act bans non-arc-resistant jacketed CSST in new construction and major renovations. | Customer-owned gas systems in Maryland. |
| 2024-2025 | CSA LC 1/CSA 6.26-listed CSST becomes mandatory in many Canadian jurisdictions; U.S. states and localities tighten inspection checklists. | Residential and light-commercial gas systems in code-adopting regions. |
Who is most affected by the new rules?
Homeowners in houses built 1990-2006 are now advised to have licensed electricians and gas fitters inspect whether CSST is present, bonded, and grounded, because many systems from that era predate uniform bonding rules. Utility safety bulletins note that unbonded yellow CSST increases the risk of lightning-induced leaks; properly bonded systems, by contrast, reduce the likelihood of arc-to-CSST events by an estimated 70-80% in modeled scenarios.
Contractors installing gas piping in new construction or major renovations must now select arc-resistant or lightning-certified CSST, verify listing to ANSI LC 1/CSA 6.26, and route the tubing with appropriate supports, sleeves, and striker plates. Inspectors in jurisdictions such as Maryland and various Canadian provinces increasingly require visible CSST bonding jumpers and documentation that the installer followed manufacturer instructions.
How the new rules affect safety and liability
Insurers and code officials argue that the updated CSST bonding and listing standards collectively reduce the probability of lightning-related gas leaks by clarifying which tubing types may be used and how they must be electrically integrated with the building. A 2022 technical review by a Canadian safety association estimated that full compliance with CSA B149.1 and B149.3 bonding requirements could cut lightning-related CSST incidents by more than 90% in high-risk areas if existing systems are retrofitted.
From a liability standpoint, many jurisdictions now treat non-compliant CSST installations as code violations, which can complicate home sales, insurance claims, or future remodel permitting. Some insurers offer minor premium discounts or waive special surcharges for homes that document CSST bonding and grounding upgrades, treating those modifications as measurable risk-mitigation steps.
Expert answers to Csst Gas Line Rules Update Sparks Debate Are Homes Safer queries
What are the main new technical requirements for CSST?
Under the latest national and regional codes, CSST must be listed to ANSI LC 1/CSA 6.26, mechanically supported at specified intervals, and electrically bonded to the building grounding system unless the tubing is certified for lightning-strike protection. For non-arc-resistant jacketed CSST, a direct bond using at least 6 AWG copper wire and UL 467 clamps is required, typically connected to the nearest segment of rigid customer piping or brass fittings, not to the gas supplier's facilities.
Are older CSST systems required to be retrofitted?
There is no universal mandate that every existing CSST system be retrofitted, but many states and provinces strongly recommend that properties with CSST installed before 2006 be evaluated by a licensed electrician and gas fitter. If the tubing is non-arc-resistant jacketed and not properly bonded, upgrading the bond to meet current NFPA 70 and manufacturer instructions is treated as a risk-reduction measure rather than an automatic requirement.
Why are non-arc-resistant jacketed CSST rules being tightened?
Non-arc-resistant jacketed CSST is more prone to puncture when a nearby lightning strike or surge passes through the piping system, because the standard jacket does not provide sufficient electrical insulation to prevent arc-through. Arc-resistant or lightning-certified CSST incorporates thicker or specially formulated jackets that can withstand higher transient voltages, reducing the incidence of arc-to-CSST events in field studies.
How do utilities handle CSST in their territories?
Several investor-owned utilities have issued internal CSST bonding policies specifying that all CSST-based customer systems must be bonded to the building's electrical grounding system near the natural-gas meter, using appropriately sized wire and approved clamps. These policies typically prohibit bonding to the utility's gas facilities and clarify that CSST must never be used as a grounding conductor for appliances or electrical equipment.
What should homeowners do if they suspect CSST in their home?
Homeowners should visually inspect accessible areas such as basements, crawlspaces, and attics for flexible yellow or black tubing connected to gas appliances, then confirm its presence and condition with a licensed plumber or gas fitter. If CSST is confirmed, especially in homes built between 1990 and 2006, arranging a bonding and grounding inspection by a licensed electrician aligned with current national fuel-gas code standards is strongly recommended to address lightning-related risks.