very slow gas leak

 I have a very slow gas leak in my house that I simply can't find.

The gas is leaking at a rate of 1.7 cubic feet per day (0.071 cubic feet
per hour) as measured by the meter.

I don't smell gas anywhere, and I have looked at (sniffed actually)
every joint I could reach, and nothing.

My question is how sensitive of a detector would I need in order to find
this? I have seen detectors with ppm sensitivity ranging from 50 to
2000. Obviously price goes accordingly, how sensitive of a detector do I
need?

And realistically speaking, how bad of a leak is it? I know that any
leak at all sounds scary, but a leak so slow that you can't smell it is
not a fire hazard as far as I know, but it does waste gas.

    -Ariel

 

What gas appliances do  you have in the house?

 Pilbs wrote:

I have a water heater, stove (range), and furnace, but the valves to all
of them were off, plus the valves internal to the units were off as well
(just in case) when I tested this.

    -Ariel

 

===============
Just a remote possibility.................

Have you got a dripping hot tap somewhere on the water heater circuit? It's
possible that the water diaphragm has become weakened and is allowing the
gas valve to operate at a lower pressure than it should. I don't even know
if this is possible but it's worth a quick check around even though you said
the valves were turned off, just in case you missed something.

Cic.

 
Why worry about finding it yourself?   Call the gas company, and tell 'em "my
gas appliances are all off, but the meter is still running".   That should get
some folks who know what they're doing out in a jiffy -- the gas company just
hates the publicity when a house blows up.