Water Heater gas line

Does code allow the supply gas line going into a gas water heater be flexible? or must it be black pipe?

I can't speak for all areas, but in my area, you use black pipe to within a couple of feet or so from the appliance, then a shutoff valve followed by flex line. I can imagine how something like a kitchen stove that was recessed between cabinets could be plumbed otherwise, and without flexibility, it seems to me any appliance would be very difficult to install.

This is a local code question. There are places that require hard pipe all the way, and here in California, flex connectors are mandatory.

In KY it must be black iron to the valve. 1/4 turn gas shutoff, drip leg and union ground joint. Not many earthquakes in this area.

Flex gas lines are only permissable where the appliance (gas stove or dryer) conceals the gas line from damage/possible break from situations around it.

codes vary

the safest way to run a gas line to any
applliance is with a flexible SS supply line...from the gas stop.
especially to the water heater.....


and they are fantastic time savers if you put in a lot of
water heaters

everyone is running wardflex and other SS gas systems
throughout the whole home, and running a flexible
gas ine directly do the water heaters everywhere in the
new home construction.

so its really just a matter of where you live....

I had a lady one time pull into her garage and just about drove
the water heaterinto the living room....

the water ines were flex, and the gas lines was a flex line so
nothing bad happenned except she had to buy another heater.