Drip legs

Is there a spot in which a main drip leg might exist so that each appliance (water heater, furnace, etc…) wouldn’t need it’s own? Is a drip leg only needed if the pipe is above the appliance? I’ve seen a couple of furnances without drip legs but the gas pipe ran underneath the furnace and connected to the flex gas line which ran upwards to connect to it. Just trying to understand a little better when i don’t see them why that is. thanks

This help?



I no longer call out their absence because the code enforcement people here don’t think it’s a big deal. It’s not enforced at all by our local AHJ unless it’s an industrial installation. The local gas company has no problem with their absence in houses. For me, it was a pain in the rear.

The line runs under the furnace…
at the point where the line runs up to the furnace a drip leg should be installed, replacing the elbow–**IF **a drip leg is required by the local utility company.

A drip leg may or may not be required in your area,but they do serve a purpose.The drip leg can catch any loose pipe filings, pipe dope,cutting oil ,moisture and anything else that could get into the gas valve.I always recommend they install one.Matt.

Drip legs are generally required by the gas appliance manufacturer.

Absence of drip legs are noted on every report where applicable.

I note drip legs as a safety issue, a cheap one at that, to protect the appliance.

Drip legs are only required where the presence of ‘wet gas’ exists. The presence of ‘wet gas’ is determined by the utility company alone.