Using the wrong materials for plumbing connections can be dangerous and lead to gas leaks or water damage. Flexible gas line, sometimes called a gas connector, is designed specifically for use with gas appliances. While it may seem convenient, it is not safe to use flexible gas line for a water heater.
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Why You Should Not Use Flexible Gas Line for Water Heaters
Flexible gas lines are designed for gas appliances only. They are not rated to withstand the high temperatures and pressures of a water heating system. Here are some specific reasons why flexible gas line is unsuitable for water heaters:
- Not watertight – Flexible gas lines are designed with small perforations to prevent gas buildup. These openings would leak water.
- Not temperature rated – Gas line can degrade from exposure to hot water over 120°F. Water heaters operate up to 180°F.
- Not pressure rated – Standard gas line is only rated up to 1/2 psi. Water line pressure is typically 40-80 psi.
- Corrosion – Brass and copper materials will corrode from prolonged water exposure.
- Cracking – Plastic connectors can become brittle and crack over time when exposed to hot water.
Using gas line for a water heater almost guarantees it will eventually leak or rupture. This could lead to lack of hot water, water damage to your home, or even a dangerous gas leak.
Proper Materials for Water Heater Plumbing
When installing or replacing a water heater, it is important to use the proper materials made specifically for potable water:
- Copper – Copper pipe is the preferred material for water lines. It resists corrosion and can withstand high temperatures and pressure.
- CPVC – Chlorinated polyvinyl chloride plastic is rated for hot water. It is easier to install than copper but not as durable.
- Stainless Steel – Corrosion-resistant but more expensive. Usually used for connectors and valves.
- PEX – Crosslinked polyethylene is flexible tubing safe for hot water lines. Must be shielded from UV light.
Any connectors or valves should also be rated for potable water service. Do not transition from gas line to water line—run new water line to the water heater inlet and outlet.
Installing a New Water Heater Line
When replacing a water heater, take the opportunity to upgrade old plumbing. Follow these best practices:
- Use copper, CPVC, or PEX line only
- 3/4 inch diameter pipe minimum
- Ball valve shutoffs for isolating water heater
- Avoid using elbows and limit length for best flow
- Insulate hot water lines
- Install dielectric unions at connections to water heater to prevent corrosion
- Mount lines securely along joists or studs as needed
Hire a professional plumber if you are uncomfortable doing the work yourself. Using the proper materials and following code requirements will ensure safe operation and longevity of your new water heater.
Conclusion
Flexible gas line does not have the correct fittings, temperature tolerance, or pressure rating to safely withstand connection to a water heater. Always use rigid pipe or tubing specifically designed for potable hot water, such as copper, CPVC, or PEX. Taking the time to install proper new water lines will prevent leaks, damage, and potential hazards. If in doubt, hire a professional plumber for installation and repairs involving your water heater.