DIY Guide to Underground/In Ground Sprinklers

[younghandyman]

The next project I want to tackle is underground sprinklers at my place. After doing some research, I'm not able to find any DIY guides.

What I need to know is with my water pressure (which I don't know how to measure) and flow rate, how many sprinklers can I put?

How deep do I need to dig the trenches for the sprinklers, is the minimum depth just below the frost line?

How do I empty out the lines before winter comes around? I've been told that you need to blow compressed air through the lines. But if the pipes are below the frost line, why is this step necessary?

Other than that, I believe it's just connecting pipe together, is there a special kind of pipe I need?

Can I run it from a water spigot in the backyard or do I need to tap into my main water line?

Thanks,


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[larry4406]

No expert but I watched them install it at one of our model homes. Municipal water supply.

They tee’d into the main water line downstream of the main shutoff yet upstream of the pressure regulator to get full county pressure. This was in the basement. They put in a shutoff valve. After the shutoff valve they installed a large back flow preventer. This has ports for draining and admitting air for winterizing. The back flow prevents contamination.

They ran the pipe thru the wall and down to the ground. From there it was shallow 6-8” down. They had multiple zones and ran control wires along the pipe. Various green hand hole type boxes in yard at the zone valves. Controller in basement. Rain sensor outside.

I think RainBird has a website to help with sizing.

Good luck.

 

[rcktsled]

Lots of stuff on Youtube:

Check the websites for sprinlekr makers like toro.com and rainbird.com. Find your local supplier that sells to golf courses. They usually have free brochures and instruction sheets.

 

[ddawg16]

Don't worry about water pressure. Typical white PVC pipe has plenty of strength.

Break it up into zones.....figure 8-10 sprinklers per zone. You can put more, but the flow will be less....which means you water a little longer.

Do flower beds in a sep zone. Flowers and grass don't share the same water schedule.

Use 3/4" PVC for the control valves. 3/4" main to the zone area then branch off using 1/2". One of the biggest mistakes people make is not getting the pipe deep enough. To figure out the depth....figure out what type of spray head you want to use. The taller the body, the higher the head will pop out. Figure a 2" riser pipe below that....that is how deep the trench should be.

Make sure you use threaded 90's at each head. One neighbor glued everything. F'ing idiot.

On the flower beds...pipe can be shallow...use tall fixed risers. I like the little fixed heads that put out a star pattern. I had a riser about every 6'. By being able to see the riser, less chance of digging into the pipe.

Try to avoid daisy chained sprinklers. Do a main branch and tee off it. That will give you the most even pressure and flow.

Feel free to sketch up something and post it.....we love offering free unqualified advice

 

[younghandyman]

No expert but I watched them install it at one of our model homes. Municipal water supply.

They tee’d into the main water line downstream of the main shutoff yet upstream of the pressure regulator to get full county pressure. This was in the basement. They put in a shutoff valve. After the shutoff valve they installed a large back flow preventer. This has ports for draining and admitting air for winterizing. The back flow prevents contamination.

They ran the pipe thru the wall and down to the ground. From there it was shallow 6-8” down. They had multiple zones and ran control wires along the pipe. Various green hand hole type boxes in yard at the zone valves. Controller in basement. Rain sensor outside.

I think RainBird has a website to help with sizing.

Good luck.

Thanks for the information. I'm going to have a plumber do the cutting into the main and installing shutoff after that. I can do everything after that.

Do you know if I have to use PVC pipe outside or can I use pex pipe? I have no idea what I can or can't use, just noticed the builder used pex pipe instead of copper in our basement so I'm asking.


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[younghandyman]

Don't worry about water pressure. Typical white PVC pipe has plenty of strength.

Break it up into zones.....figure 8-10 sprinklers per zone. You can put more, but the flow will be less....which means you water a little longer.

Do flower beds in a sep zone. Flowers and grass don't share the same water schedule.

Use 3/4" PVC for the control valves. 3/4" main to the zone area then branch off using 1/2". One of the biggest mistakes people make is not getting the pipe deep enough. To figure out the depth....figure out what type of spray head you want to use. The taller the body, the higher the head will pop out. Figure a 2" riser pipe below that....that is how deep the trench should be.

Make sure you use threaded 90's at each head. One neighbor glued everything. F'ing idiot.

On the flower beds...pipe can be shallow...use tall fixed risers. I like the little fixed heads that put out a star pattern. I had a riser about every 6'. By being able to see the riser, less chance of digging into the pipe.

Try to avoid daisy chained sprinklers. Do a main branch and tee off it. That will give you the most even pressure and flow.

Feel free to sketch up something and post it.....we love offering free unqualified advice

Thanks for the tips.

Given the size of our backyard, we'll probably need only 8-10 sprinklers, and I also want to run the pipe to our front yard.

Do I have to use PVC, can I use pex pipe?

I will definitely posting my drawing once made.


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[velocipede]

In my area of Virginia the sewer $$rates are tied to water meter readings,i.e. use more water, pay more for your sewer. Here, you can install a separate irrigation water meter and use it to have your sewer fee adjusted. Check your locality to see if this is a concern for you.

 

[yeldogt]

Find a local rainbird or hunter supplier -- many will sell to homeowners. They also have the info -- but you can download it.

Years ago -- they were deeper with drain valves. Today with the number of "installers" around you can get a system blown out for $80 -- so the pipes are installed close to the surface. You need a low pressure high flow compressor to do it correctly -- that's why you see them pulling the large compressors when they blow them out.

You want to use quality heads. Go to both hunter and rainbird on the web and start reading. Buy a few head types after you have done some layouts.

Personally -- I do all of mine in 1" pipe. 1" valves. Regular S40 up to the valves and thin wall after. Makes it easy ... have one pipe and fittings to buy. The price difference is small and it's a better layout. I make up swing fitting for each head vs going "funny" pipe. Drop some sand in the hole ... makes adjustment easy in the future.

They have fitting to make up the manifolds -- easy that way. My last job I used rainbird valves and hunter heads ..

drip is great for planting beds -- have to be seperate zone .. and the zone valve needs to be for drip (low flow)

I also typically have a spot where a yard hydrant (for a hose) is nice .... drop an extra pipe in when I'm doing the trench .... they make fittings that pop in and out and you don't see them in the lawn.

Again -- get the information. You measure your water pressure and follow basic guide. When not sure .. make another zone.

Stay out of big box stores

 

[argulator]

Everything and more than you want to know-https://www.irrigationtutorials.com/

 

[jdsac]

Rainbird offers a free design service with a materials list-

https://www.rainbird.com/homeowners/free-sprinkler-design-services

 

[CraigStu]

Lowes in N Va sells Rainbird components. Nice to have a place you can walk into and grab what you need. Do more rather than less zones. For instance our property was half yard and half tall trees. A couple of the zones covered from the tree line to maybe 80 feet away so all that area got the same amount of water. I know this could have been worked out by using different rated sprinkler heads, but I always wished the first 40 feet nearest the trees was a separate zone from the other 40 feet so I could have adjusted the time different to put less water in the area w/ more shade. BTW the system needs to be blown out because no matter how deep you put the connecting pipe/tube, the sprinkler heads are right at the surface. SO that means put the pipe only needs to be as deep as ddawg described. BTW, down the road keep one of each style sprinkler assembly on hand. they say you can take them apart to clean out the filter and sometimes that works. But at about $12 each, when one isn't spraying, just dig a little around it a little w/ a hand shovel, unscrew it and screw in a new one.

 

[Super Mech]

I did mine about 22+ years ago. Went to a Rainbird dealer with a sketch of my property with measurements. All materials cost me about 650 back then that’s including the timer and valves with the valve box. Mine are about 8” deep on average. I blow them out myself at the end of the season. Never broke a pipe due to freezing and I still have a fair amount of original sprinkler heads. A few have been broken by my gardener but I replaced them. My cousin and I did the installation in two weekends.

 

[SGKent]

Rainbird has information online that gives you all the answers you need. You will need to know what kind of pressure your system will have. A simple gauge that screws onto the hose bib is available at any Lowes, Ace, or Home Depot. Once you do that, turn on the shower or something with ample flow and see what the pressure is. If you have a pressure regulator be sure you are on the side of the regulator that the sprinklers will come off. The Rainbird site will tell you how much water each size pipe will handle, and how much each valve will handle at pressure. Then pick out the style sprinklers you will use. From that you can figure how many can go on each valve. You try to build the design so that they aren't all in a line or the last one will get a lot less water pressure. Then you figure overlap and where to put them.

If this is a lawn, most cold season grasses grow best at 2" - 3" height so you will want probably 4" popups. Add three to four inches for a riser and that gives you a depth of about 8" for the pipe - or deeper depending on the depth of where things heave in your area. Where I am the ground does not freeze.

Keep in mind on your overlap that depending on the sprinkler you need up to 50% overlap or there will be completely dry spots.

In fact Rainbird will even design a system for you if you send them the correct information. https://www.rainbird.com/homeowners/free-sprinkler-design-services

 

[Red 17]

Funny pipe, just rubber hose, installs easily, allows less fiddling with the main line, and IF SOMEONE STEPS ON YOUR SPRINKLER IT DOESN'T BREAK THE MAIN LINE.

 

[Git]

As others have mentioned, Rain Bird has a free service that will design a system for you. You do need to know your water pressure and gallons per minute beforehand, so they can figure out how many sprinklers per circuit.

A couple of notes - I would look into a 'smart' controller like a Rachio. It makes it a lot easier setting up each zone (circuit) by looking at things like type of plant, root depth, how much shade, flat or sloped ground, etc. For people like me in California, it saves water/money by automatically cutting back on the water needed based on the weather.

Definitely go with the 'funny pipe' fittings. It really makes getting the sprinkler set at the right height and position a heck of a lot easier. They call it a 'flex pipe swing joint' and has a threaded 90 degree fitting on each end - one screws into your branch line and the other into the sprinkler body. If you ever need to move a sprinkler over a couple of feet, you can buy a roll of the flex pipe and pull of the 6" piece and replace it. You can buy them already made up or just the pieces and make your own

SprinklerWarehouse.com has some great prices and tutorials

 

[niget2002]

This is the tutorial I used to design mine

https://www.irrigationtutorials.com/landscape-sprinkler-system-design-tutorial/

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[yeldogt]

Funny pipe, just rubber hose, installs easily, allows less fiddling with the main line, and IF SOMEONE STEPS ON YOUR SPRINKLER IT DOESN'T BREAK THE MAIN LINE.

Except -- it has a habit of coming off ... don't like the stuff. That's why I said to the OP not to use in my post.

The rainbird preassembled things above are decent ... although I just buy the parts and have the ******* is a couple sizes. The made up swing joints hold the head in place ... easier IMO. too high ..push down. Too low...pull up.

If someone steps on it == it just goes down.

 

[sqznby]

My system's lines are all PVC. It has two different size pipes, the main line is a bit larger cant remember what size but T-ing off into each head is 1" Sch40 PVC pipe.
All the flower beds have drip or mist attachments and the driveway has smaller twisting heads.

Our system is set up to run 3 heads per zone. Not sure who has 8 to 10 running at once but, they must have an amazing pump to supply the water haha.

Depending on your water supply system, heads and angles chosen you may not need so many heads.

Our system is fed from a well specifically for irrigation.

 

[Jinks]

The next project I want to tackle is underground sprinklers at my place. After doing some research, I'm not able to find any DIY guides.

What I need to know is with my water pressure (which I don't know how to measure) and flow rate, how many sprinklers can I put?

How deep do I need to dig the trenches for the sprinklers, is the minimum depth just below the frost line?

How do I empty out the lines before winter comes around? I've been told that you need to blow compressed air through the lines. But if the pipes are below the frost line, why is this step necessary?

Other than that, I believe it's just connecting pipe together, is there a special kind of pipe I need?

Can I run it from a water spigot in the backyard or do I need to tap into my main water line?

Thanks,

Sent from my iPhone using The Garage Journal mobile app

Once again, if we knew where you are we could tailor our answers to better help.

Without that, here are my experiences. You can go to any irrigation provider for guides on sprinkler systems. Or, pick up a DIY book at any big box store. A shallow well will cost less than city water. Here, if you must use city water, it's better to put in a separate meter so you aren't charged sewage for the water used.

For pressure put a pressure gauge on whatever outlet you plan to use. It'll tell you your pressure. For flow open the outlet fully then catch as much as you can in a bucket for 30 seconds or 1 minute. Do the math for the gal. per minute flow.

Know the distance you will pipe the water from pump, outlet, whatever. 1" pipe is good for some distance, but any real length requires better flow. I use 1 1/4" pipe to feed a zone, & 3/4" to feed each head. I also use flex pipe between feed pipe & head.

Hunter makes the best gear drive heads. For impulse or pop up heads RainBird is fine.

 

[Innovate1]

Several people have mentioned PVC. Many are put in with black poly pipe - mine is. Some seem to think PVC is better and others think poly is better. My risers for the RPZ and valve manifolds are PVC. The rest is poly. Poly can be plowed in which means less digging and tearing up the yard but probably hard to find the machine for rent.

Several have mentioned good sites like irrigationtutorials.

For a small system you can blow it out yourself with a small compressor. I have a 1 hp compressor with about a 15 gal tank. I blow out a zone and then wait for it to recharge a couple minutes before the next one. I have a large system but also have a controller that I can program for delays between zones so I just set it up and it cycles through the zones. I was able to snag a bigger tank, about 30 gal, that was going to scrap so I have been using both but just the smaller one worked.

What is required for backflow varies by location. It may also require a plumber to put it in and/or annual testing.

 

[SGKent]

I use six to eight on each circuit. City water and a pressure regulator set to 57 PSI. Drops to about 45 with the sprinklers on. Use the micro spray sprinklers because they use less water. The problem here in Sacramento is the soil, mostly clay. Takes forever to dry and 10X as long to wet. If one lets the top dry it just runs off. Adding amendments is near impossible, they just burn out. That said, 30 years of doing it has improved the top 4" to 5" of soil.

When you dig your trenches, unless you have really fertile soil keep the top soil separate because it will take years before the soil on top is as fertile as what was there. I ended up with trench lines for a couple years before grass would grow on them due to the poor soil. Compact it a little if you can or you will get trenches every year when it rains.

 

[Red 17]

I've had over a dozen on swing joints for 10 years. None come off. But we don't get a freeze here either....

 

[Innovate1]

That's the beauty of a pipe plow. just leaves a small line in the soil that quickly closes up and leaves the grass. Won't work in soil with much or big rock though.

 

[Git]

I have never had a 'swing joint' come off either (S Cal)

SGKent - sounds like you need a good 'smart' controller that uses 'cycle and soak'. If your grass need 30 minutes of watering for example, but everything is running off after 10 minutes, you can set it up so it waters for 10 minutes, goes into a 'soak' cycle (stops watering and waits for the water to soak in) and then repeats until it can get the 30 minutes of watering in

 

[SGKent]

I have never had a 'swing joint' come off either (S Cal)

SGKent - sounds like you need a good 'smart' controller that uses 'cycle and soak'. If your grass need 30 minutes of watering for example, but everything is running off after 10 minutes, you can set it up so it waters for 10 minutes, goes into a 'soak' cycle (stops watering and waits for the water to soak in) and then repeats until it can get the 30 minutes of watering in

The timer waters twice about two hours apart. That allows the soak. The sprinklers used to be sprayers but now they are this mini rotor style which also helps. They go off in the early morning but even if windy they don't mist and blow away.

 

[sqznby]

SG,

What model heads are they? I like that pattern, seems to cover a decent area.

 

[Git]

That looks like a Rainbird Rotary
https://www.sprinklerwarehouse.com/products/lawn-irrigation/sprinkler-heads/rotary-nozzle-sprinklers

Check with your water company and see if the have any kind or program for sprinklers. For example, in my area, here is a list of high-efficiency sprinklers they will give you a rebate for

http://socalwatersmart.com/files/pdfs/qualifying_list_nozzles.pdf

 

[engineer2]

Had a system in my previous house. A few thoughts:

You can get a simple pressure gauge to check your water pressure. If you are on municipal water, and have at least a 3/4" line coming to your house, it will probably be OK. Tap into your main water line for best flow/pressure. Water flow limits how many zones you can run at once.

If your town has even/odd day watering restrictions, you may want a sprinkler timer with that provision.

My sprinkler lines were only a foot deep at most. Frost heaving in our area tends to push everything up over time. You want to be deeper than a rototiller can reach. Ask me how I know that, LOL.

You should try to slope everything towards the control box, but this may be impractical. Compressed air to the rescue! Install a hookup for compressed air between the system shutoff valve and the control valve box. You do not want to backflow compressed air into your water system and you need to blow out the control valves too.
I would do it in the fall and manually cycle through each zone, maybe 10 minutes, then do it again to make sure I got everything.

Sprinkler heads get destroyed occasionally, usually from lawn mowing. Keep a few spares. Not hard to replace.
I remember spending time re-aiming sprinkler heads too.

 

[ford33]

Without a location for the OP it is difficult to help.

I use my small 20 gallon air compressor to blow out water from the lines at the end of the season. I connect it to each zone one at a time and blow out the water with several cycles of high pressure releases into the pipe. I have a small system so it doesn't take much air. You may need someone with a larger air tank.

 

[rayra]

PVC is ridiculously easy to use, assemble, repair, and it's pretty sturdy. And it's INEXPENSIVE.

Seconding zones. Learn how to assemble a proper manifold arrangement of your valves, one that will readily allow replacement of valves years later.

There's nothing hard about sprinkler installation. If you find yourself having a hard time, you are probably doing something wrong.

 

[sqznby]

That looks like a Rainbird Rotary
https://www.sprinklerwarehouse.com/products/lawn-irrigation/sprinkler-heads/rotary-nozzle-sprinklers

Check with your water company and see if the have any kind or program for sprinklers. For example, in my area, here is a list of high-efficiency sprinklers they will give you a rebate for

http://socalwatersmart.com/files/pdfs/qualifying_list_nozzles.pdf

Cool, thanks for the info, I appreciate it.

Not sure if that's directed towards me but, my irrigation system is on its own separate well. Which happens to be collapsing, so a new one is in the very near future haha.

 

[rick carpenter]

My home watering system is redneck cheap. I use pop-up Toro heads with each having a series of pipe and elbows up to the surface. Threaded pvc fittings are glued to them (laying flat) then male qc adapters are screwed in. They are buried in holes in the ground and locked into place with pea gravel. I have female qc connectors on the end of several black Craftsman 5/8" water hoses. During watering season, I leave the hoses laying in the yard connected to the heads. I cut my grass high and the hoses don't show from the street. I have to roll them up each time I mow and all winter, but the heads stay below mower cut height.

 

[Falcon67]

Still, as easy as it all is, sometime after you've done your install - maybe years - you'll still like it but refer to it as your "irritation" system. Heads clog, valves leak, rotators break, replacements run the wrong way or backwards so you buy three different price levels to find one you like, one rotator moves nice and slow, the next one spins like a turn table, valve lids pop off under the mower and get chewed to hell and so on.

 

[sqznby]

Still, as easy as it all is, sometime after you've done your install - maybe years - you'll still like it but refer to it as your "irritation" system. Heads clog, valves leak, rotators break, replacements run the wrong way or backwards so you buy three different price levels to find one you like, one rotator moves nice and slow, the next one spins like a turn table, valve lids pop off under the mower and get chewed to hell and so on.

Don't forget collapsing wells That's if you're depending on one for your irrigation system. We are

I like it "irritation" and I can definitely relate. My first summer in the new house and never dealing with an irrigation system, I replaced 4 heads and just as many solenoids. Never mind hiring someone to find a hidden valve covered by the thickest centipede grass. Now, my well has started to collapse so my irrigation system is out of commission and my entire system is contaminated with silt throughout. I cant run any type of sprinkler and the only hose attachment I can use is one of the big firetruck nozzles which I have to keep adjusting so the silt will go through. Yay