Question
One of the valves in my drip sprinkler system serves two separate areas of my yard.  Recently the water pressure in one area has dropped dramatically while the other area (same valve/zone) remains good.  No apparent leaks noted. Could a bad valve cause this?  Any ideas would be appreciated.  thanks

Answer
Hey Mark, I hope this helps. If you're not seeing any visual leak on the weak side of the system, I would suspect some kind of restriction. My suggestion would be to start at a section that has good pressure(maybe check the 1/4" small tubing at a plant) and then go to the next plant and check it there. Try to isolate where the pressure seems to drop. Then follow one of the small tubings back to the main poly line. Once you have found the main poly line, expose it a little at a time, and see if you see a kink or restriction anywhere. This is a common occurance, especially if you have any big trees or plants (roots). Once you find the restriction, simply cut this piece out, and install a new section. Let me know if you have any more questions, thanks and have a great day.