The one home inspection item that consistently causes home buyers to ‘freak out’ more than anything else is a gas leak. Gas explosions like the ones that recently happened in Edina and Saint Paul are probably the main causes of all the paranoia about natural gas.  Believe it or not, small gas leaks are actually quite common at old houses, and they’re usually simple for a plumber to fix.  Today I’ll share the most common locations for gas leaks, and I’ll share my home inspection techniques for finding gas leaks in old Minneapolis and Saint Paul homes.

The most common place for me to find gas leaks is at gas valves.  Older style gas valves that aren’t allowed any more today are often referred to as lube valves or plug valves.

These valves are easily identified by a nut or spring on the valve, across from the handle; newer gas valves don’t have these.  I would estimate that I find leaks at about one out of every five of these valves.  Gate valves, which should only be used for water, are also common offenders.

The repair is always simple – replace the the valve.  In Minneapolis, if the appliance being served by an improper valve is replaced, the valve must be replaced at the same time.

The second most common location for gas leaks is at unions.  A gas union is a fitting that provides a disconnection point for a gas appliance.  If the union doesn’t get tightened enough, it will definitely leak.  Notice the bubbles in the union below?  That’s a small gas leak.

Flare fittings are the last common offender.  Here in Minnesota, soft copper gas tubing is allowed just about anywhere, but it takes a little more skill to properly install soft copper than other types of gas piping.  For a flare fitting, copper tubing gets flared out at the end and connected with a flare nut.  If this connection gets bent or isn’t tight enough, it will leak.

To find these gas leaks, I mostly rely on my nose.  If there’s a gas leak, I can almost always smell it.  To pinpoint the location of a gas leak, I use a combustible gas detector.  If I see any suspicious work or I run across old or improper gas valves, I just go right to my gas detector, and I quickly check the fittings.

I truly believe that my nose is just as accurate as my gas detector, but I look a little silly running my nose along gas pipes to find leaks.  That’s why I use a tool.  If I find a leak with my combustible gas detector, I confirm the leak by using a gas leak detection solution; it’s just an expensive blue liquid that does about the same thing that dish soap would – it bubbles if there’s a leak.  To make it easier for the repair person coming in behind me, I also mark the location of the leak with orange electrical tape, and I write “Gas Leak” on the tape, along with an arrow showing exactly where the leak is.

I’ve heard stories about appliance connectors leaking, but I’ve never found one that leaked. Next week I’ll talk about defects with appliance connector installations.

RELATED POST: Natural Gas Leaks

Reuben Saltzman, Structure Tech Home Inspections - Email - Home Inspector Twin Cities