Water in patio gas grill buried gas line.

J. Rogers

I am using natural gas to fire my outdoor grill. The builder left a 1/2 in. nipple stubbed out about 9 inches above ground. I attached a valve, then ran black pipe down 14 inches underground, then elbowed horizonally and used a transition fitting to yellow polyethylene pipe for fifteen feet to the edge of the patio. I converted back to black pipe, and at the surface I added another valve and a quick disconnect fitting.

All worked well for many years, but now I find I have water in the line and had to remove the disconnect fitting, turn on the gas and blow some of the water out before my new grill would burn properly. I don't believe I have any gas leaks after excavating both ends of the line. So, I am doubtful that water is somehow entering the line from the ground, as suggested by a gas company employee.

I understand there is often a small amount of water in the gas line as it is delivered to the customer. This fact I believe suggests the wisdom of installing a drip leg or sediment trap. I note this line is clearly the lowest point of my gas line piping and currently has no trap.

Question: Where do you think the water is coming from and what should I do about it? If I built a sediment trap below the nipple, coming out of the exterior wall, would it be a good idea to put a valve at the bottom of the trap, so that the water could be occasionally drained from the line?

Thanks for you help. J. Rogers

VIPlumber

Sounds to me like the nat gas being delivered does have a bit of water in it.

Yes, the best solution would be to have a drip leg installed at the lowest point, in fact it's now a code requirement. The drip leg should consist of the Tee, nipple (~3"), ball valve, another nipple, and then a cap. The reason for the cap is in case the the ball valve inadvertently gets knocked open, thus stopping the outflow of gas.