Question
I have 3 sprinkler heads in 2 different areas of my yard that are always wet. They aren't leaking enough to show up on the water meter (it doesn't change any in an hour or so). Should I still be concerned about them and fix or have them repaired? What is the best place to look first to figure out what's leaking?
Thanks, George

Answer
Hi George

There are a couple of possibilities to consider.  If the heads that are always wet are located at the bottom of a slope, they may be subject to low head drainage.  This implies that when the zone finishes watering, the residual water remaining in the lateral line drains to the lowest point in the line.  Depending on the length of the line, it could be a little or a lot of water.  If it's a lot, it can take a while to trickle out of the low head(s).  The solution to low head drainage is to install a check valve at the base of each head in question.  Hunter & Rain Bird have these accessories available.  Make sure you get the appropriately sized valve - spray heads and mid range rotors use 1/2" and larger residential rotors use 3/4" thread. They are typically effective in holding back water on 10' slopes.

The other issue to consider is known as a "weeping valve"  This occurs when the diaphragm in the valve doesn't completely seal against the seat allowing just enough water to continually flow through the valve to your sprinklers.  Sometimes there's debris in the valve which can inhibit a good seal.  I would doubt this is the issue because this problem would make the dial on your meter move, albeit slowly.

Hope this helps.

Tony