# Beginning my DIY irrigation journey



## 7824 (Oct 23, 2019)

I do not want to take on this project, but it seems I have no choice. I need to irrigate roughly 15,000 sqft of my lawn. It is cut up into three sections. 7k, 4500k, and 3500k. That will allow me to water sections on different days. My well is 4gpm, 400ft deep. Good water pressure.

I had the two local irrigation installers come out. One quote was $6,300. He spent time walking, measuring, and marking with flags. He explained everything in detail. He didn't want to put more than 2 heads on a line due to my well specs. Lots of zones. He was very knowledgeable, detailed, and I was impressed. Unfortunately, it's way more than I can spend. The other company did not get back to me, even after I called and left a voicemail to follow-up after a month.

It seems the other irrigation companies are too far away to service my area. I'm prepared to spend $3500 for a professional install, but apparently that is unrealistic in my area. It's time for me to start researching DIY costs to see if this journey is worth it.


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## TSGarp007 (May 22, 2018)

Are you sure you only have 4 gpm?


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## 7824 (Oct 23, 2019)

I may be mistaken. Here is a screenshot of the test results. The recovery rate was determined to be 4.12 gpm. It looks like the output for the first hour was 8-9 gpm. After an hour, it drops off quickly and then holds steady in the 4 gpm range. When I did the 5 gallon bucket method, it took 45 seconds to reach the 5 gallon mark. That was using the hose-end after a 4 way splitter and 150ft of hose.


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## TSGarp007 (May 22, 2018)

Well I'm not a pump expert, but if the well company did the test then I guess we'll have to accept it. You have a lot of yard to cover with not much gpm. It will take you nearly all day to water the yard to 0.5" of water. You'll also need a lot of zones I think, because each zone will be small due to gpm limitations.

Did you just get the well installed?


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## 7824 (Oct 23, 2019)

I have the option to alternate days and sections, as it's divided up by the driveway, sidewalk, fencing, front, back, and side yards. I wouldn't need to water more than 7k sqft per morning. I have about 15k sqft total to keep irrigated. The back 10k sqft does not get supplemental irrigation.

The well was dug 9 years ago just before we bought the lot. The pump and everything else was installed brand new when we built the house last year.


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## hsvtoolfool (Jul 23, 2018)

With only 4 GPM, you'll need lots of zones with very few heads running together (as your local installer guy said).

The math is easy. Just look up the GPM requirement for a head type and sum the total. You want to remain below 4 GPM for any zone.

For example, if you use "rotor" heads at about a 30-ish foot radius (like the Hunter I-20 or the Rainbird 3500 series), each head requires about 1.4 to 1.5 GPM. So you'll be limited to perhaps 2 or 3 heads running per zone.

The other approach is to use more "rotator-y" spray heads at a 20-ish foot radius (like Hunter MP-2000 "Rotators", or Rainbird RN "Rotary Nozzles"). As an example, a rotary 360° nozzle requires about 1.5 GPM at 20 feet. So again you are limited to about 2 to 3 heads per zone.


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## 7824 (Oct 23, 2019)

I read the cost for a professional installer ranges from $500-$800 per zone, under typical conditions. What is the average cost per zone for a DIY install using high quality components? I know that can be broad, but still weighing the pros and cons.


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## g-man (Jun 15, 2017)

It is hard to come up a number since there are too many variables. Each zone needs a vavle. They go for around $20 each. Then the heads with nozzle or rotors are around $15. Add to this the ft of PVC or polypipe, fittings, one controller.

The irrigation pump analysis was spot on. He did it the right way. The 6k quote might not be too off. With 4gpm, you will have a zone/pipes for each head. Trenching/digging will be a challenge.


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## TSGarp007 (May 22, 2018)

I recommend just diving in and start by measuring and drawing your property with the areas that need irrigating. Then figuring out your sprinklers and positions to get head to head coverage, and from there start dividing it up into zones. I recommend trying to use the Hunter MP Rotators due to their gpm. You may end up with a LOT of zones, but if you have your mainline loop (or nearly loop) throughout your yard and have valve boxes in the field instead of one or two central locations, then you may be able to minimize excessive piping. Then you can make an actual estimate of the costs.

Maybe in the end you decide to only irrigate a portion, or save money for a deeper/more productive well, or get a separate irrigation meter from the city (if that's an option), etc. But this initial design will get you a lot closer.


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## hsvtoolfool (Jul 23, 2018)

TSGarp007 said:


> I recommend trying to use the Hunter MP Rotators due to their gpm.


I agree that's true for small, irregular areas at 20-foot head distances. But the OP has some rather large areas to cover with very little flow. Once you need throws around 30-feet or more, I think it's almost always better to use rotor heads. The single rotor stream is both more robust at longer distances and has a lower GPM. From my experience with MP Rotators, the real-world _effective_ radius is well shy of the catalog specs.

For example, the Hunter MP-3000 360° nozzle uses 3.6 GPM at 30-feet. The Hunter I-20 rotor has a 1.5 GPM nozzle that shoots 30 feet. Since the rotor shoots a single, revolving stream, it allows 2 heads to run together and covers more area per zone.


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## 7824 (Oct 23, 2019)

The installer that came out proposed using 26 rainbird 5004 heads and 7 rainbird 1804 heads.


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## TSGarp007 (May 22, 2018)

Very true @hsvtoolfool.

Good sign about the one installer recommending 33 sprinklers, could be worse. I don't suppose he left a layout of any kind? Really need a layout of the area before you can decide on what sprinklers.


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## hsvtoolfool (Jul 23, 2018)

@learningeveryday, so I'm guessing he spec'd about 16 valves/zones? If his estimate was $6,300, then it works out to about $400 per zone (which is not too bad). It's a difficult install due to your low flow rate.

I figure you have about $3K in bare DIY numbers...



Rainbird 5004 rotors = $13 each x 26 = $340


Rainbird 1804 with nozzle = $6 each x 7 = $45


16 valves at $20 each = $350


Well water means I'd install an easy to flush and clean, 60 and 100-mesh stainless in-line filters before the valve manifold at about $100 for a pair. You can just install a 100-mesh, but having a 60-mesh "pre-filter" saves the second one from clogging.


I don't know the requirements for running irrigation from a well, but I'd personally add a 1" Zurn Wilkins 1-375 Reverse Pressure Zone (RPZ) backflow preventer (after the filters) for around $220. There are cheaper backflow options, but none more effective than an RPZ. This design is very clever and quick and easy to winterize. Just shut off the cutoff valves and take the entire middle section indoors. Need a rebuild in 4 or 5 years? Just order a whole new middle section. Pretty cool.


16-zone "smart" controller = $250-ish. Search the forum for debates on what's "The Best". I love my Rain Machine HD-16; others swear by Rachio, Hunter, Rainbird, etc..


1" and 3/4" PVC pipe and fittings = $1,000 (_Wild A**ed Guess_: not enough data to estimate)


Rental trencher = $150 per day x 4 = $600. You've got a LOT of trenching, but the soil really determines how long this chore takes. If you have nice soil, you might finish trenching in a day. As a worst case, it took 2 days to trench my 3K SF front yard! We have hard clay soil in Rocket City, which means lots of chert bowling balls to jam trenchers. Rocks are a huge pain and really slow you down. 

Now factor in your time, possible injuries, and a difficult design causing things to go wrong later, and it may be worth paying someone to do the job and get a warranty. If $6.3K is tough to swallow in one big bite, just prioritize sections and do one area per year.


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## 7824 (Oct 23, 2019)

I haven't asked for a layout yet. I didn't want to waste too much of his time if I not 100% sure I will use a pro. I'm sure he has it drawn up. He's very busy, time is money, and I don't believe I should see it unless I decide to have a professional installation.

Thank you for that breakdown. That is extremely helpful. $3k in DIY sounds about right for a $6k pro install.

His quote included 15 rainbird remote DV100 valves, wireless rain sensor, one 4 station auto controller, two 6 station modules, pipes, fittings, etc.


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## hsvtoolfool (Jul 23, 2018)

My list includes items that some DIY folks would omit/substiture like the RPZ and the filters. You can look up the prices of your installer's recommended gear and come up with your own list. I rounded up so you can probably get the cost lower than my guesses.

If you're going to DIY, please read and absorb the entire Jess Stryker Irrigation Tutorials web site. It answers every possible question and is easy to read. Follow his rules, do the maths, and you won't go wrong.


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## Chungus (Jul 26, 2020)

$6300 for 15k square feet and 15 zones is a steal in my opinion.

As many have alluded to you are going to have to run your sprinkler nearly all day every day to get an 1" of water a week on that much area with such low flow. Say it is divided into five zones watered per day so three days to water it all. By day four the first zone you watered needs watered again. If $6,300 is out of your budget have you thought of the costs of your well running non stop seven days a week? It wouldn't surprise me if it added $100 a month to your electric bill.

I'm not sure if you have ever done any kind of project like this before but 15 zones over this much area is a lot of work. If you are doing it yourself with no help I wouldn't be surprised if it took you 10-15 days to do.


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## TSGarp007 (May 22, 2018)

My math could be off here, but...

If the pump uses 1,000 watts (1 kw) (1/2 hp)
Electricity costs $0.15 per kwh
15,000 square feet -> 2.16 million square inches
To water one inch that is 2.16 million cubic inches -> 9351 gallons
That will take 9351/6 = 1558.5 minutes ~= 26 hours
1.0 kw * 26 hours = 26 kwh
26 * $0.15 = $3.90
Do that every week of the year and it averages out to around $17 a month. Double that if it's 1 hp pump. Obviously cost of electricity could be different. Efficiency is an issue. But there'll be lots of months with no irrigating...


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## Chungus (Jul 26, 2020)

Your math looks good except he has 4 GPM not 6 so 39 hours to water everything. Definitely costs less than I estimated but to water everything in three days that is 13 hours a day of sprinkler time. With such low flow OP might have issues trying to do anything like take a shower, a load of laundry, etc while the sprinkler is running.


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## TSGarp007 (May 22, 2018)

Chungus said:


> Your math looks good except he has 4 GPM not 6 so 39 hours to water everything. Definitely costs less than I estimated but to water everything in three days that is 13 hours a day of sprinkler time. With such low flow OP might have issues trying to do anything like take a shower, a load of laundry, etc while the sprinkler is running.


Oh yeah, I think I was confusing topics or something. Not sure where I got the 6 gpm. Do we know it isn't a separate irrigation well? If that is shared with the house, it's a bit of an issue. I think each house is supposed to get 6 gpm min as a rule of thumb, right?


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