From tank to home — the path
Propane travels through five components in sequence:
- 1. Tank — stores liquid propane at ~120 psi (at 70°F)
- 2. First-stage regulator (on tank) — drops pressure to ~10 psi
- 3. Yard line / service line — buried polyethylene or copper, carries 10 psi from tank to house
- 4. Second-stage regulator (at house) — drops pressure to ~11 in WC for appliances
- 5. Home piping — distributes gas to each appliance at 11 in WC
Yard line / service line
The buried line from tank to house is typically polyethylene (PE) tubing for new installations, or copper for older systems. PE is preferred today: corrosion-resistant, flexible, easier to install. Standard depth: 18–24 inches below grade. Marked with locator tape or tracer wire above the line to prevent accidental excavation damage.
Two-stage regulation
Two-stage regulation (first stage at tank, second at house) is the US residential standard for tank-to-house distances over a few feet. It allows higher pressure in the yard line (smaller pipe diameter for the same flow) while delivering safe low pressure at the appliance.
Home piping
Inside the home, propane piping is typically black iron (steel) or CSST (corrugated stainless steel tubing). Each appliance branches off a manifold; each appliance has its own shut-off valve. Piping sizing follows NFPA 54 (National Fuel Gas Code) — too-small pipe causes pressure drops and appliance malfunction at peak demand.
FAQ
How long should the yard line be?
As short as practical, while respecting NFPA 58 tank setback rules. Typical residential installations: 20–100 ft from tank to house. Longer lines need larger diameter to avoid pressure drop at peak appliance demand.
Can I extend a propane service line myself?
No. Service line modifications require a licensed propane technician and permits in nearly every US state. Pressure testing and leak verification are mandatory after any modification.