High water bill, part of lawn stays soggy wet.

[Randyj]

I'm by far not an irrigation expert. Though I've read a lot and have been to classes on irrigation there's a LOT that I don't know about lawn irrigation systems. So, will appreciate any knowledge I can gain from you guys.
Here's the deal. I do a lot of maintenance work for this guy at his vacation home. He bought this house 2 years ago and has had nothing but problems out of the irrigation system. He thinks his water bill is outrageously high. I have no clue if it is or not.
Kind of wild guessing I'd say his system covers about 4,000 to 5,000 square feet (not measured). He has 8 zones on a Rainbird system that covers his lawn, 4 flower beds and probably 4 beds that are mostly shrubs. (I'll get more info today... maybe). The tests I run show there is no leak in the water supply line between backflow preventer (check valve) and the solenoid type valves (zone valves)... (holds 90 psi air for more than 15 minutes). Main supply from meter is 1" PVC with 70 psi pressure.
With valves to his garage, house, and irrigation system turned off the main supply line (about 1,000 feet from meter) shows 31 gallons of water per day are going through the meter. His water bill reflects that he paid for about 24,500 gallons of water last month. His controller is set to run the system 10 to 20 minutes (various times) for one cycle per day. This works out to somewhere around 942 gallons of water per day when irrigating.

There is a slight valley along a hillside between his lot and his neighbor. This valley stays soggy wet when sprinkler system is running. No other obviously wet areas.
The lot is roughly 100' x 150' with a house and garage that has a footprint of roughly 3,000 sq. ft.
This is the type of controller/timer he has. http://www.rainbird.com/documents/tu...ESPModular.pdf

My question is... (1)Does this sound like a reasonable amount of water for a relatively small yard.
(2) What suggestions do you have for looking for a leak in one zone? (I'm thinking he may have one zone gushing water out of a broken pipe after a valve in the wet area). (3) what range of volume of water output can be expected from a typical "pop up" lawn sprinkler of the rainbird type? (where can I find info for estimating output for designing a system?... estimating water output).

[Gary Swart]

I had a similar problem recently. Thought I had a broken pipe, and since I don't dig anymore, I call my lawn service. Turned out the problem was the pop ups were all very old and were leaking big time every time the zone watered. New pop ups and the problem was solved. Try turning the zone on and watching the pop ups very closely. I'll bet you see water pouring out from around the caps. You don't have to really excavate a big hole to replace the pop up, just a shovel deep cut around the head and lift that much out. This will expose enough of the pop up to allow its removal and for a new one to be screwed on. If I had realized this, I could have save some $$ on the service call.

[Randyj]

Thanks Gary. For a relatively modest size yard... does over 900 gallons of water sound like the volume it should be getting in one cycle for 8 zones with a few sprinkler heads? I figure it's coming out to an average of over 3 gallons per minute per head.... so, kind of betting on some free flowing water some where.

[Gary Swart]

Sounds like a lot of water to me. A little added info to my previous post. The newer Rainbird popups have a white ring around the top and the seal at the bottom when the pressure is off. The old models like the ones I had were solid black and not seals. Easy to tell the difference. It may be you are watering too much as well. The technical information you want should be available at a decent irrigation supply. I would not rely on accurate information for Big Box Stores. Chances are pretty good the person you would talk to there won't have a clue. Again, to check the heads for leaks, just turn the zone on and look. If they are bad, there will be water running out in addition to the spray. As a side note regarding pipes. I installed my system in 1984. (That's not a typo) In those days, PVC pipe was thin wall and would break quite readily if hit with a shovel. In all the years this has been installed, I have had one broken pipe. That was the main pipe from my back flow preventer and it broke because the control box the BFP was set in had settled and the box lid was setting on top of the BFP. I stepped on the lid while mowing, and that broke the 1-1/2" pipe. Never have had a 3/4" pipe break, but all sprinkler heads are connected with Funny Pipe so the will take the shock of being stepped on. If your head are connected with solid pipe, then it is possible there could be a break. If your popups are not leaking from the tops, then let the ground dry up, and then turn the zone on and patrol the area and watch for wet spots to appear.

[Randyj]

Thanks Gary... good info and tells me what to look for. Even with the system off for a couple of days I've never been there and not found the soggy area wet. I'm wondering if the neighbor doesn't contribute to that problem. It may be tomorrow before I get a chance to get back over there to check flow on each zone.