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New Member

Posts: 2

Location: USA


Sunday, June 26th 2005, 11:03am

Need QA on my new design


I wanted an irrigation system installed at my house and decided to DIY after a very expensive quote. I was told $6500 for an 8 zone design, no way. Rainbird helped with their design service which got me headed in the right direction. So now that I have purchased most of the components I would like some review before I cannot return or exchange anything.

I have city service with about 60psi at 14gpm delivered with a 1" galvanized line. I am having a landscaping company tap into the water main and provide me with a 1" SCH40 PVC connection after the backflow preventor. Including all the "in yard" trenching, the cost is $650. Good price? I think it is ok, but I don't have a comparison.

My design uses 15 zones, most of which are for my extensive flower beds and side yards. Rainbird designed 16 zones, but I feel 15 works well and maybe even 14 if I can regulate my flow rates. Average water usage per zone is 12gpm, working at about 40psi at the furthest head. Using the 100DVF valves in four manifolds, 3x4 valves and 1x3 valves. Rainbird suggested two 8 zone controllers, but I went with the 16 station ESP-LXi. I am not planning on drains considering I am north of Seattle and we rarely ever get below freezing. Should I have a Tee installed to blow out the lines?

I am using Rainbird 1800 spray heads for the beds and side yards. For the front and back yard I am using R-50 rotors. There are some tall bushes I have and I was thinking inside the bush using a 12" pop 1800 which is suspended about 20" out of the ground. This way the head retreats back into the bush when done, instead of a little nozzle poking out of the bushes every 8 feet or so. Plus, this would accommodate further growth and pruning.

Each zone is limited to no more than 13 gpm, given throw distances this did necessitate the 15 zones (14 if I work it). The lot is 16,000 square feet with about 4,500 of that being residence and 5,500 being beds. One of my questions is line size. Looking at the prices for SCH40 1" and 3/4" PVC there is about a $0.80/10' difference. Given I need 1600' of pipe would it be alright to drop to 1" main line and 3/4" service or "zone" line. This would save me about $400 in fittings and pipe. With that, what is the benefit of going from SCH40 to Class 200 PVC? In that there is another $0.40/10' savings. Maybe I shouldn't be looking for cost cutting routes if I want a good system, but money is money and I don't have tons of it. Already I am looking at about $1800 for the whole deal, which is better than the $6500 for contractors.

At first glance what do ya think? I usually research the piss out of everything that I do. I consider myself a very capable person, usually opting to DIY everything unless I have potential to really mess up (e.g. tapping into the mainline). Thanks for any input, it will be appreciated!



Supreme Member

Posts: 314

Location: USA


Sunday, June 26th 2005, 6:14pm

Sounds like you've got a pretty decent start so far on your homework for the system. I will try to answer all of your questions, and there are other professionals here that will throw in some advice as well.

First of all, if the $650.00 includes the tap, and running the line outside, and installing the backflow, and includes materials, then yes, I would say that is a good price. You say you don't have anything to compare it to though, I think it is always a good idea that homeowners get at least three quotes on everything they do. Not only to compare prices, but also to get a feel for other contractors, there may be one out there that you feel is more professional, and that you trust more. Just a suggestion.

Good choice in going with the 16 station controller, I wouldn't suggest two controllers, and I am not sure why they did, that is just a problem waiting to happen.

Not having automatic drains is fine, you don't need them, and really, by draining your lines after each use, you are just wasting water by having to re-fill your lines at each use.

I would have a tee installed so that in the event of a freeze, if it happens, you have a way to blow out your system. It is cheaper to have it installed now, then when it is 20 degrees outside, and at the last minute.

For the amount of PSI and gallons per minute, I wouldn't be using 3/4" pipe just to save money, the friction is going to reduce PSI, and compromise the operation of your system. I would use a minimum of 1".

PVC pipe is rated by two different systems, the first is the "class" system (Cl) the other is the "schedule" system (SCH). One type is not always better than the other. Schedule pipe is rated by the pipe's wall thickness, while class pipe is rated by the pipe's operating pressure.

Your non-mainline pipes should be CL 200 PVC and buried at least 10" deep (12" deep is the industry standard for commercial irrigation systems). Many homeowners use the CL 125 PVC pipe because it is cheap, but it breaks easily and they often regret using it later. If you can't find CL 200 PVC then use SCH 40.

If you think about it, $1800 for an irrigation system of that magnitude, installed yourself, is a heck of a deal. On a DIY job where you can save some serious money on labor, I wouldn't risk cutting corners on materials. Good Luck.
Tony Posey
Ridge Run Landscapes


Supreme Member

Posts: 372

Location: USA


Tuesday, June 28th 2005, 7:34am

Good summary by Tony. just want to add that I 100 percent agree on using 1 inch. Pushing 12 gpm through 3/4 inch is not smart from a standpoint of velocity also.



New Member

Posts: 2

Location: USA


Thursday, June 30th 2005, 6:59am

Thanks for the input so far!

I have the landscaping guy comming in a few minutes to talk over the mainline tap and where to trench. I cannot wait for hm to complain about my design considering he is losing $6000 of business because of it. They are a good company though so it shouldn't be so bad.

I have come around about the PVC issue. It makes sense to me now. There is no reason to skimp on it and I can afford it, I just usually try to penny pinch like crazy. I will be using SCH 40 for the mainline and then Class 200 for the servicing lines. Anybody know of a cheap place on the internet to get fittings? I found a place called LASCO which seems to be a crazy deal, but I think you have to be a retailer though . . . darn.

Thanks again and I will be frequenting the forum for awhile.



Supreme Member

Posts: 5,292

Location: Metro NYC


Thursday, June 30th 2005, 10:15am

Lasco is one of the manufacturers of PVC fittings. For your quantities, though, the home improvement stores might be as good as plumbing suppliers or irrigation suppliers. Everyone's mileage will vary.

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