Large Scale Central

Drip Irrigation

Hey all you gardeners.

I am getting ready to start running the plumbing to my layout. Wish i would have done that during construction but I have brain damage so its okay. But I was smart years ago when I ran my new service line from my meter to my house to put in a Tee and a stop and waste valve in the ground with a stub of pipe for a future underground sprinkler system. This is in a very convenient location to run my layout drip system from. Now I am a water guy buy profession but not really and landscape irrigation guy. I know enough to get myself in trouble. The line feeding it will be 3/4" at about 65 psi static pressure. More than enough to run a drip system on one station on my small layout. I will be also adding a hose bib faucet to run a hose in our front yard more conveniently than of the house. Still should have more than enough water even if I did run them at the same time.

Here is my plan/thoughts so far. I can come off my stub with a Tee to the faucet and then to a station valve. From the valve to a AVB (atmospheric vacuum breaker) for backflow protection (required) all of this being 3/4" then after the AVB Tee that to two runs of the 1/2(?) drip feeder line, the kind you stab the laterals into, one for each of the two sides of my layout. Then the various laterals to the various plants I have/will have as needed. All of this run off a single timer located in my yard cabinet which has power to it.

Does anyone see in inherent problems with this simple design. And suggestions/improvements I am not thinking of. I know little to nothing about drip systems. And when I say drip I am including the little sprayer nozzles possibly also. But mainly just the little soaker/drip type stuff.

I have one tree back there that I planted to give shade. It is supposed to be a deep rooting kind so it won’t lift my layout. I worked with an arborist to find the right tree for this location. And she said to give it long deep soaks. Should I run a second valve/AVB combo to the tree so that It can be run longer than the other plants? Seems I might over water everything else if I do the same long soak for the tree. She recommended watering it with a soaker loop for two to three hours at a time once to twice a week. Seems to me this will be a very different watering schedule than small plants.

This is what I used. Lowe’s had them and they’re pretty cheap. Comes with just about everything you need.

Easy to hook up and comes with different size emitter heads, couplings, and small hose for the emitters to provide as much water as you need.

Course with all the rain we’ve had in the last year, I haven’t had to use it…(

I have used the micro sprayers, the tubing with slits, the tubing with the “drippers” inside every 6 inches and inside every 12 inches and the separate drippers.

I have about 12 different watering circuits (which includes 2 lawns).

What I have learned:

  • drip hose with slits is garbage, but pretty much no longer sold.
  • drip hose with the internal drippers every so many inches is pretty nice, make a circle at the perimeter you want, more water, get closer spacing or 2 loops or both. good stuff lasts 10 years
  • micro sprayers make a mess and clog, but might be good in cases where you have roots evenly spread, but mostly like grass
  • the single drippers (about diameter of a quarter) come in all sizes of gallons per hour, and are very flexible in “tuning” the water needed.

The more “tuning” of the “drippers” the fewer independent watering circuits you need.

I would have at least 2 circuits if not 3 (the tree is way more water and like you say a completely different type of watering)


Get a starter kit, they usually come with the correct back flow preventer and pressure regulator. This is the one I started with: Drip Irrigation Which ever kit you get, make sure they have add on pieces available, and don’t forget to put a filter on your head end.


I figured on one of those types of kits. Although mine will not be ran from a hose. It will be a dedicated system with its own connection to the service line. But the other pieces and parts would be usable.

Greg thanks for the low down on the various types of attachments. While I have the sprayers in the back of my mind, like you said I have heard they like to clog, and honestly with only one exception I don’t have any spot that would need broad cast watering. Most everything will be individual plants. I am sure at least two stations will be required at a minimum because of the tree. That will have entirely different requirements than everything else. So with that said how many dripper things whether solo or loops would reasonable be able to be run of a single station? This is not going to be a terrifically plant intensive layout. With half of it being elevated bench like Ken has there will only be potted plants here and there. And the other side is pretty skinny and narrow beds. Remember my whole layout is only ten feet wide with a walk through the center of it.

Here is a thought. As I already mention I plan to have one leg of the system run down the bench work side and another leg run down the raised bed side. I pretty much had planned to have that run off one station valve with a Tee right at the valve for each leg. I could always install it with one valve and add another should it not be sufficient. Or I just suck it up and two a total of three from the get go and be done with it. The amount of cost between two stations and three really wouldn’t be all that much difference, an extra valve and an extra AVB.

For those that don’t understand and might care when you install permanent irrigation systems many water purveyors have rules on backflow prevention. Part of my duties at my water utility is I am the certified Cross-Connection Control Specialist. This is a fancy title that says I went to an 8 hour class and passed a test on recognizing potential cross contamination hazards and knowing the proper devices to prevent backflow events from happening. A cross connection is any connection to a potable water system to a system out of the control of the water utility, this generally excludes interior plumbing (but not always). A garden hose is a cross connection. Now my job is to determine if that cross connection poses a risk to the public water system should backflow occur. Backflow happens either with back pressure, where the cross connection can produce a higher pressure than system pressure, or when water can be sucked back into the system by siphonage due to a loss of system pressure. Not all cross connections are considered a risk. In general regular plumbing in a house is not a serious risk. Unless you are doing something weird in your house most houses have internal backflow protection primarily an air gap where the discharge is higher than the receiving vessel (your kitchen faucet and sink). or it has a vacuum breaker such as on hose bibs at least in newer homes. So we are not normally concerned wit them. 99% of the time we are most concerned at a residential level with back siphonage. What can be attached to a hose or pipe that if the system loses pressure that can get sucked back into the system. Hot tub connections, Swimming pool fillers, hose chemical sprayers, horse watering troughs underground sprinkler systems where the dog poops on the sprinkler head. I could go on and on about all the possibilities. But I will save you the details.

Now I have a mixed attitude toward this whole thing. Like most things when the gubberment gets involved they go way overboard in creating a policy that is way more stringent than is really necessary. As a general rule I have very little concern about the average household contaminating my system. But here is my PSA part of this discussion. Backflow prevention is far more serious to you the home owner than it is me the public system. By the time your contamination hits my system it will be highly diluted. But what scares me is what you can do to yourself and your loved ones. This is a real issue and one htat I think people should take serious at least on its basics. If you use chemical sprayers on the end of your hoses, please please please install a very cheap vacuum breaker on the threads of your hose bib if you do not already have hose bibs with them built in. These will break the suction should the public system or your own house lose pressure. Same goes if you have pond fillers, hot tub fillers, swimming pool fillers, horse trough fillers etc that fill their containers with a direct connection that is below the flood rim of the vessel. So the filler pipe should have a gap twice the distance as the diameter of the pipe between the rim of the vessel and the pipe. both of these will prevent water you don’t want being sucked back into your house. What can and has happened is the public system loses pressure because of a broken pipe or through a venture effect from a sudden high demand like a fire where fire hydrants are being used. when this happens it will suck this nastiness into your water system where it is not diluted so much and when the pressure comes back on it pushes it to all points of your plumbing including the faucet your drink from. There are documented cases of people getting sick and/or dying from their own contamination entering their house. The fixes are cheap and can save your life.

I say all this in case people are wondering about the AVB I keep mentioning. That’s what they do and I wont have a system without some sort of protection. There are all sorts of devices depending on the conditions and the hazards that are faced. If you take this to heart and are concern, as I hope you are, then contact your purveyor and ask them for guidelines on what they not only require but recommend. While most everyone uses the same standards they do very some from jurisdiction to jurisdiction. If you want my suggestion beyond what they tell you or if you are on a well with no governing authority I will gladly walk you through it. I used to be passe about it but I have heard of to many cases where bad things have either potentially happened or actually happened.

You are over thinking it Devon. Drip systems have been around for years using the simple back flow preventer. I’ll give you time to find the cases where that has caused a health issue in anyone.

The BFP is safeguard enough because unlike a sewer or water service line there is no pressure pushing back against it. Once you turn the water off, and it dribbles out and runs to the low end of the line, what issues are you going to have? I most cases, the head end parts, (regulator, BFP and filter) are up higher than the system. If you are that worried, put a downward slope in your main line away from your head end.

Sprayers will clog over time. They are CHEAP, not a lot to worry about.

It’s not rocket science. It comes with a pressure regulator that reduces the flow into the drip system. Mine hooks up to the garden hose. Turn the faucet on to water, turn the faucet off to stop. Pretty simple. No back flow problems.

Chris Kieffer said:

You are over thinking it Devon. Drip systems have been around for years using the simple back flow preventer. I’ll give you time to find the cases where that has caused a health issue in anyone.

The BFP is safeguard enough because unlike a sewer or water service line there is no pressure pushing back against it. Once you turn the water off, and it dribbles out and runs to the low end of the line, what issues are you going to have? I most cases, the head end parts, (regulator, BFP and filter) are up higher than the system. If you are that worried, put a downward slope in your main line away from your head end.

Sprayers will clog over time. They are CHEAP, not a lot to worry about.

Sorry Chris,

I kinda strayed with my last post. I didn’t mean to give the impression that a drip system was a risk. They aren’t. My water purveyor requires a minimum protection of an AVB on all directly connected irrigation systems. My PSA was more to explain why I would install a AVB which is the most minimal protection shy of an inline check valve. But more than that to raise awareness of OTHER potential hazards around the home. so to be clear I am not the least bit worried about a drip system causing a problem. My water system and the one I work for has set a minimum protection level for directly connected irrigation systems based solely on what can happen if someone is stupid. Remember in my job I am tasked with keeping the system as safe as I can form general stupidity. I am not worried about the people who know what they are doing, I am worried about the one who comes later who doesn’t know what they are doing and attaches an injection pressurized fertilizer system to their sprinkler system (yes I have personally disconnected one in the field where this happened).


while the hose is connected to the system disconnect it from the faucet and suck on it. Can you suck water back through the hose? If so back flow can and will happen. You are thinking only back pressure, not back siphonage which is actually the most common type of back flow event. There are all sorts of reason back siphonage can occur and I have personally watched it happen. We had a broken water main that was still draining water into a muddy hole and then all of a sudden it looked like a toilet and all the mud was sucked into our water main. WTF? Well a guy down the small incline, not knowing the water was off, opened his two inch irrigation pipe which was lower than our muddy hole. Now thank God we were able to flush it easy enough, take a bacteriological sample and it came back clean and we were able to restore service. But as a precation we required a boil order for the people on that chunk of mainline until we could confirm it was clean. Point is it can happen.

Again on a drip system we are talking a very low risk. One I wouldn’t worry about. even a simple single check valve would be more than enough. My system requires an AVB and for the 10 bucks they cost I won’t fight it. On your system if its a relatively newer house chances are you already have one, most newer hose bibs have them. If not for a few dollars they have one that screws on the threads and then you scre your hose onto that. Why not have a that very simple and cheap piece of mind. hose bib vacuum breaker 7 bucks seems pretty cheap

and if your hose bib looks like this one your covered anyway

Now if you all still think I am crazy then please carry on. Will you get sick or die, probably not. Its just an issue that is cheaply prevented.

Devon, the amount of drippers that run on a line is related of course to the total gallons per hour you are using, and also consider the water pressure.

Some people are adamant about pressure regulators, some say why? Some people regulate to 30 psi (amazing), and of course the number of drippers on a run will go down.

I’d guess somewhere out there the GPH of 1/2 line vs pressure is written down.

See if that link helps… it does quote capacity of 1/2" feeder line.


Understand why you need the AVB. Never put it past the government to make things more complicated than they need to be. But I agree that at minimum you should have a back flow preventer.

Back to your original question. My water source is in the center of my garden, so I have a tee right away and 2 legs running off. No problems with that, but my runs are only about 30’ each. If it was me, I would definitely run a dedicate line to the tree. Better yet, get a dual timer and put the tree on it’s own schedule.

I have a pressure regulator installed because the manufacturer requires it, max pressure of 25psi on my system. My system is not long enough to do without it.

Will be interesting to see how this works for you. I want to install drip on my elevated RR like Ken did for future planting.

Guys, please take notice of what Devon is talking about with backflow events. They are not as rare as one may think. As Devon stated, most all water providers, including the one I manage, require backflow preventers at the meter to protect the public system, but that does not protect the home itself. AVB’s are cheap insurance against this type of event. Now, I agree that a drip irrigation system is not a high hazard connection and the likelihood that it could cause a problem is near zero, but what’s the harm in adding a device, cheap one at that, to make sure it is absolutely zero. My 2 cents, YMMV (

Damn water guys sticking together. Lol.


I agree and the more I dwell on it at a very minimum the tree will need it’s own station and time schedule. I will need to research sprinkler timers as I know they will do multiple stations but not sure if they allow individual stations to be timed differently. I assumed so, but really have no clue. While I know everything about cross connection ( know little to nothing about landscape irrigation. And even above that I think I would rather over engineer it and run three stations, one for each side of the layout and one for the tree. Maybe way way more than needed but then it’s all installed at once and I doubt I will ever say “darn it I wish I would have done two instead of three”.

Pressure regulation should be a real breeze. Maybe I can talk to my old surgeon and get my old shunt valve back. (

Here you go buddy: 2 zone timer

Pick an irrigation system, they will have a pressure regulator available already set to their system. Don’t use your shunt, it didn’t work.

Chris Kieffer

Don’t use your shunt, it didn’t work.

Good point. Lol.

That timer is for hose connections which would work. But I was thinking more like the type used for underground sprinkler systems. If I didnt over think it, over design it, spend too much money on it, and make it harder than it needs to be then it just wouldn’t be me. Other than that I was just thinking that’s how it should be. But after seeing the kits you guys are suggesting I could do the hose bib timer and hose connections, still have my beloved AVBs and make it work a whole lot simpler than what I was thinking.

See that’s why I ask. I know you guys will take care of me and protect me from myself. . . Most of the time.

If you want field faucets, then run 3/4" PVC to solenoid valves that interface the PVC and the irrigation pipe and drippers. That system remains under pressure and can feed your faucets.

You’ll want on/off valves and unions in line for repairs, in each feed line.

Chris Kieffer said:

Here you go buddy: 2 zone timer

Pick an irrigation system, they will have a pressure regulator available already set to their system. Don’t use your shunt, it didn’t work.

I use a similar timer. It has a really stupid computer, but it can be programmed to water once to several times a day, for one to 99 minutes, but they are not flexible. What you get in the morning is what you get for the rest of the day. The two can be programmed separately, and for once or several times a week, or once a day, or several times a day. It helps.

DO NOT USE THE WATER PRESSURE DESIGNED TO RUN LAWN SPRINKLERS!!! Unless you like watching those little drip heads launch into orbit.