Month: May 2013

How to Connect Main Line, Backflow Prevention and Pipe

Garden Enforcer Full View

Last week we discussed the different types of pipe used commonly used in sprinkler systems.  We discussed how to lay out the pipes for your system and how to dig the trenches.  Finally we discussed timers and their placement.  This week we’re going to go further in the process by connecting to the municipal water source, installing any necessary backflow prevention and putting pipes in the ground.

Connect Water to Main

Where your water comes from will determine how you connect into it.  For most people, the water source is a municipal water line buried in the ground.  If you connect through a well (which requires a pump) then the hookup to the main line is the same, however we won’t be discussing installation of the pump this week.  Either way, the irrigation mainline will take water from the source to the valves.

Irrigation mainline is a high quality of pipe.  It must hold up under constant pressure.  It should have a higher pressure rating assigned to it.  To avoid any breaks the pressure rating of the pipe should be about double the actual water pressure.  Perhaps this appears to be too much, but to account for any pressure surges in the system, this higher pipe rating is recommended.

Main-lines come in many materials and sizes, just as we learned about the irrigation piping from last week.  There is PVC, Polyethylene (Poly for short), Galvanized metal pipe, or Copper metal pipe.

Now that we know what and where our water connection is, the first step is to dig to expose the water service line, or to expose the existing tap, faucet, etc.  Once you shut off the main water supply (which is probably near your meter), open a faucet to release any existing pressure, to avoid accidents.

Water to your property comes from one place (the meter) and runs into your house. To have water for your sprinkler system you’ll need to branch off this line and run it to the valve box.  Do this by connecting a ‘slip tee’ fitting, which will simplify the repair/installation process.   These fittings allow for water to continue to pass from your meter to your house, and also to be used for irrigation needs.

To install a Slip Compression Tee follow these four steps:

  • Clean off the water service pipe
  • Cut out a section of the pipe-half the length of the tee

  • Install nuts and washers on each side of the pipe

  • Insert the slip tee and tighten the nuts with a wrench.

Next, we connect pipe running to the valve box, is to install a shutoff valve.  You should still have your main-line shut off valve coming off the water service line that will then go into your house, but, don’t forget to have one as well for the irrigation mainline.  To properly install a shut-off valve follow these steps:

  • Use fittings to install a Gate or Ball valve on the tee

  • Turn on water to flush the line of debris

  • Cover with an Orbit valve box

In the above example, notice how the water line runs from the meter into the house (in black) and we break off of that for the sprinkler main line (in red).  Just after branching off we recommend installing the Gate or Ball valve.  This lets us easily shut off water to the sprinklers without also shutting off water to the house.

Backflow Prevention

Local codes may require you to install backflow or anti-siphon prevention.  Even if they aren’t required, we suggest installing one or the other.  

The valve featured to the right is a 1 In. Double Check Valve Assembly.   This valve prevents harmful contaminants from siphoning back into the water supply.  It also  functions as a main shut-off valve.

The photo to the right features another type of backflow prevention device called an anti-siphon valve.  The valves should be positioned such that water drains away from the house.  These particular valves need to be installed a minimum of six inches above the highest sprinkler head.  There must be no back pressure on the valve, and no valve on the downstream side of the anti-siphon.  As you can tell, these devices are very important to have on your line to keep the water safe.  Check with local code/authorities what type of device is required, how it needs to be installed, and who is authorized to install it.

Connecting Manifolds

In our previous blogs we covered placement of the valve box.  It is now time to discuss how to install the valve box.  Dig down 8 to 14 inches, depending on the box, and place about two inches of crushed gravel.  This will allow excess water and condensation to drain without sinking the surrounding area.  Next, place Orbit’s valve box base on the gravel.  Watch this short movie on the benefits of using Orbit Valve Box Base.

Before connecting the manifold to the mainline, open the main shut-off valve to flush dirt from the main sprinkler line.  Next, install your manifold.  The easiest way to install a manifold is with an Orbit Pre-Assembled manifold.  These manifolds install in minutes, works with Poly-Pipe and PVC  systems, and expandable for future sprinkler systems.  Watch this short movie to learn more about Orbit’s Pre-Assembled Sprinkler Valve Manifold.

Last week we also talked about the wiring necessary for the timers.  It’s a good idea to make these connections now.  Follow the instructions for connection.

Working with Pipe

The different types of pipe have been discussed previously.  Upon choosing your pipe type, remember that each has different assembly requirements.

PVC is harder to work with, as it doesn’t have much give to it and isn’t flexible, but it is stronger.  Fittings can be tricky though.  It’s need two compounds (primer and cement).  First, apply the primer, which works to slightly ‘melt’ the pipe and fitting, making just enough room for them to slip together.  The cement then forms a permanent, watertight seal.

If you decide to use traditional fittings, remember to follow the instructions precisely as stated, allowing the cement to dry completely (usually 1-2 hours) before running any water through pipes.  Failure to do so may cause incorrect setting of the glue, leaving leaks for water to escape or debris to enter.  Once the pipe and fitting are joined they cannot be separated or moved, so make sure to set them correctly within the first 10-20 seconds of joining.  If a mistake is made the fitting must be cut from the pipe (and discarded, it is now useless) and a new fitting joined.  The pipe can be reused assuming it is long enough.

In this picture the PVC fitting is attached using the primer and cement to seal the fitting onto the pipe.  As is common, a poly riser is attached at the sprinkler head.

PVC with PVC-Lock™ fittings

Orbit has created new fittings that work with PVC pipe that eliminate the need for primer and cement (and long drying times).  PVC-Lock™ fittings seal tightly by using rubber o-rings and stainless steel gripping teeth.  All you have to do is push and turn and the pipe is ready to go.  Check out this link to view the difference PVC-Lock will make on your install.  If a fitting was put on incorrectly, in can be removed and used again.  To free the fitting, simply slide the Orbit PVC-Lock Release Tool around the fitting connection and pull the fitting and pipe apart.  PVC-Lock fittings can swivel on the pipe to ensure accurate installation connections.

Poly Pipe

As depicted PVC pipe is inserted into the PVC-Lock™ fitting easily for a secure watertight seal.

Poly pipe can be equally frustrating as correct installation requires the use of screw-clamps to secure all fittings.  These steel clamps hold the fitting tightly, allowing great amounts of pressure to easily through.  It is recommended to not use Poly pipe for the main line to the manifold.  There is some advantages though, as Poly is usually less expensive and it’s flexibility means less fittings.


Similar to Poly pipe, yet functional with poly and PVC fittings, Eco-Lock® is the best of both worlds.  Using the Eco-Lock®  fittings (similar to the PVC-Lock™ fittings) you simply push and turn to have an instant seal proof connection.  Eco-Lock® fittings can swivel on the pipe to provide 360-degree directional adjustment as well.  The ability to use these fittings to retrofit any system with existing PVC or Poly fittings is a must have.

With all these pipes you’ll need some tools.  A pipe cutter, measuring tape.

Join us next week as we will detail how to install the mainline, install manifolds, and connect zones.

How to Diagram and Install Pipes, Trenches & Timers

Last week we covered how to select and place heads, as well as how to create zones and place manifolds. This week we’ll be moving further along in the design process and even get into some installation.

Picking up where we left off, we are now going to diagram our pipe layout. First, you will choose where to cut your mainline to add a tee fitting. This tee fitting will make it possible for you to maintain water flow to your home, while still having water flowing to your sprinkler lines. The line connecting your sprinkler line and main water line will need a shut-off valve. Including the tee fitting and shut-off valve, draw a line from your mainline to your sprinkler valve box. From the valve box, draw header lines out to each zone. Look for opportunities for piping to share trench space. Once you get your header lines out to the zones, draw lateral lines. From these lateral lines you will attach a riser that a sprinkler head will connect to. Please continue reading for more detailed explanations and diagrams.

What Type of Sprinkler Pipe Should I Use?

There are two types of piping used in residential sprinkler systems: PVC and Poly pipe. Though there are other types of pipe, these the are the two that you’re likely to encounter. We’ll discuss both briefly here, plus Orbit’s contribution, Eco-Lock Sprinkler Pipe.


PVC is generally considered the stronger material used in residential irrigation, but recent developments have made us re-evaluate that view. PVC is a hard, white plastic pipe. It has very little give to it, and is thicker than poly. PVC pipe does not bend too much (or at least shouldn’t), and if it does it will snap. While PVC can withstand higher pressures, both

PVC and poly ratings far exceed that which will ever occ

ur in a residential system.

There are some drawbacks to PVC. The way PVC is made includes the use of significant amounts of chemicals that are damaging to the environment and has led to talk from environmental and green building groups about abandoning PVC. Also, the fittings used to connect PVC pipe require the use of special PVC primer and cement.


Poly Pipe

Poly pipe is more flexible and not as thick as PVC, and its malleable properties give it added protection in freezing areas. Because it can be bent to match the contours of trenches, it is easier to work with, requiring fewer fittings, thus reducing necessary parts and installation time.  It is also more affordable than PVC. Fittings used to connect poly pipe require the use of steel clamps.

The type of pipe you choose for your system will really be a personal preference as both have their pros and cons. PVC is a bit stronger and this should be a consideration if you’ll be doing minor digging, as it will be able to withstand a certain amount of impact more than Poly Pipe (though, neither of them will withstand very much impact).  However, when it comes to repairs, the poly is certainly easier to work with.


You may have noticed that Orbit offers its own poly pipe, known as Eco-Lock Sprinkler Pipe. This green-colored poly pipe can be used with traditional fittings and our exclusive Eco-Lock fittings. PVC, as we mentioned before, is tougher to work with because it requires primer and cement in addition to its stiffness. Take it from a lot of professional experience, this is a hassle to work with. The primer and cement are messy and can’t be removed from clothes. Fittings need anywhere from 1-2 hours of dry time before you can run a system test. But Orbit’s locking fittings (both Eco-Lock and PVC-Lock) make installation faster and easier. They both operate by sealing fitting connections with rubber O-rings and stainless steel gripping teeth that are able to withstand over 1200 PSI. PVC-Lock and Eco-Lock fittings can swivel on the pipe to provide 360-degree directional adjustment.

 How do I Diagram Pipe Layout?

 Once your pipe has been chosen, you’re ready to diagram the layout. The water from the mainline enters your manifold contained in the valve box. Water is then released by individual valves to header lines. Header lines are usually no smaller than 1 inch and no sprinklers are attached. Rather, lateral lines branch off header lines within a single zone. Risers are attached to these lateral lines and sprinkler heads are attached to the risers. Lateral sprinkler  lines are generally ¾ inch and risers are generally ½ inch pipe. The reason we don’t attach any sprinklers to the header line is because it will decrease pressure along the way, resulting in lower pressure at the end of the line. Thus, header lines are used to keep consistent water pressure. In the example below we have header line in black and lateral lines in red.

Remember, the shortest distance is a straight line, so try to make the lateral lines branch out perpendicular to the header lines.

If you’d like some graph paper to start drawing your diagram to scale, click here to download our sprinkler system preparation guide and use the graph paper for free.

Diagram the runs for future reference.

One of the unique advantages to Orbit’s Online Sprinkler System Design tool is that it maps out everything, even your pipe runs. This is useful when you put in the system, but also for future reference whenever digging is required to make repairs or add more heads. It’s nice to know where everything is years later. If you don’t use the tool, we still recommend doing this. Yards change and irrigation needs should change with it.

How do I Dig Trenches for My Sprinkler System?

Congrats! You’ve made it this far and now you’re ready to start the actual installation of your new irrigation system. First step: dig the trenches. You can dig these by hand or use a trenching machine. If you’re putting in an entire system, the trenching machine is really the way to go. If you are brave, you can rent the machine and do it yourself, otherwise, you can pay a contractor to dig the trenches for you. Although it does cost money, using the trenching machine is easier than digging by hand and you can usually dig all your trenches in a matter of hours.

[stextbox id=”warning” caption=”WARNING!”]WARNING!  Whenever digging trenches in your yard it is imperative you take proper safety precautions, starting with having your local utility lines marked. If digging by hand, make sure to maintain correct posture, and take breaks as necessary. If you do it the wrong way you’ll hurt your back. Trust us on this one. If using a trencher, follow the instructions exactly. These are very powerful machines and even experienced operators have trouble with them sometimes. We also recommend wearing safety glasses and gloves.[/stextbox]

Okay, now that we’ve covered trenches, next, mark the lines. You’ve already drawn them on the diagram of your yard, so get some sprinkler flags and mark where each head will go. Next, get some spray paint used for ground marking and paint the lines on the ground. Once this is done, you’re ready to dig. If you already have grass in, you may consider putting a tarp down to throw loose dirt on as you dig your trenches. Cleanup will be much faster this way.

The trickiest part when trenching can be getting under the driveways, sidewalks, walkways, and other rocky or concrete features. The Orbit Walkway Tunnel Kit simplifies this process. This tool attaches to a hose end and uses water pressure to tunnel under these obstacles. To use the Orbit tunneling kit, dig a trench on both sides of the walkway or driveway. Attach a garden hose to the tunneling pipe. Next, turn on the faucet and work the pipe back and forth, allowing the water to spray and form a tunnel.

Now, besides digging a trench for each sprinkler line, you’ll need to dig for the main line (which municipal code may require to be a certain depth, depending on frost line conditions in your area), for the manifold boxes and a trench for the sprinkler wire leading from the manifold boxes to where your timer will be placed.

Speaking of timers…

What Control Timer Should I Select?  Where Should I Install It?

 Timer Selection

Your timer is the brain of your underground sprinkler system. It controls when and how long you irrigate your yard. Orbit timers are known for their reliability, ease of installation, programming simplicity, and their 6 year warranty.

To help you narrow down your options, select a timer that will accommodate the number of zones your sprinkler system will need. Timers can usually control 4, 6, 9, or 12 zones. If you have more zones than this it will be necessary to purchase additional timers. Orbit offers a large selection of timers to fit your needs. They are all simple to use and easy to install. Pick the timer that suits your system’s needs and personal preference.

Timer Placement

Where you put your timer is largely a matter of preference. Timers can be placed indoors or outdoors (with the use of weather resistant housings). Indoors tends to be more convenient (if an indoor space is close) and protects the timer from the elements. If your manifolds are some distance away from the manifold boxes we recommend some of our timers with remote controls that allow you to activate the different zones from a distance, which is extremely helpful when performing maintenance.

Remember to place your timer near a power source where you can access it easily. Also, consider running sprinkler wire through underground conduit to make any future expansions or repairs easier.

Next week join us again as we continue the installation. We’ll connect the system to the mainline, install necessary back-flow prevention devices, and lay the pipe.

How to Install an Underground Irrigation System

Why should I install an underground irrigation system?

Increase Home Value and Cost Savings

Underground irrigation systems offer a host of benefits. For starters, the upfront effort and cost pay for themselves after just a few watering seasons. You will see a decrease in your monthly water bill almost immediately. An underground irrigation system can also enhance your home’s curb appeal, which increases marketability and home value.

When properly installed, maintained and operated, an in-ground sprinkler system can easily save hundreds (and in some cases thousands) of dollars in annual water costs. Sprinkler systems allow you to more efficiently regulate water to different parts of the yard, rather than a one-size-fits-all approach.

Time Savings

In-ground systems are also great at saving time. Many homeowners know the frustration associated with dragging hoses around their yards, remembering timing schedules, and trying to spot-correct problem areas. Underground sprinkler systems operate on the “fire and forget” principle: set the system properly and let it run (with only minor tweaks along the way). Ideally, you should set your sprinklers to run early in the morning, between 4:00 a.m. and 8:00 a.m. Watering early in the morning frees up the yard for outdoor activities and allows the turf adequate time to absorb the water before evaporation.

 Sprinklers running

How do I get started installing my underground irrigation system?

An in-ground irrigation system is no small project. It’s one you want to get right because mistakes can be costly and time consuming to fix. But a well installed system will yield results almost immediately and require little maintenance over the years. The following paragraphs explain how to begin the process.

Determine Local Codes

Before digging a trench or installing pipe, check with your local municipality about code requirements for underground irrigation systems, backflow prevention, and anti-siphon valves. Backflow prevention with anti-siphon valves is important to consider because it prevents possibly contaminated water for being drawn back into the main water supply lines when water pressure decreases.

Ask if a permit is required to install a system or if a licensed plumber is necessary to connect your main line. If you live in a freezing area, pipes need to be buried 8-12 inches deep. You may also ask for recommendations on pipe size.

Your municipality may offer the option to use reclaimed water. Reclaimed water is sewage and wastewater that has been treated at a facility. Though the water isn’t suitable for human consumption, it is a great resource for watering yards. Besides being greener (it’s basically recycled water), reclaimed water can be significantly less expensive than regular water. However, certain precautions need to be taken when using reclaimed water, which the municipality will explain further.

Determine Water Flow

Determining available water pressure is an important step. Water pressure affects every aspect of the system including: how many zones will be needed to water evenly, the type and amount of sprinklers to add to the line, and length of watering intervals.


String Test Method

To determine the available water pressure, attach an Orbit pressure gauge (part #53020 or #91130) to an unregulated outside faucet. Unregulated means a line without a pressure regulator. Open the faucet and record the reading. No other water should be running during the test. We recommend you perform this test as close to the time of day when the sprinkler system will be operating. Pressure will generally be higher in the mornings. To be most accurate, take several readings at different times, even different days, and record the lowest one.

pressure gauge

Next determine whether your main water line is copper, galvanized, or PVC. If you are unsure of your pipe material or size, your municipality can tell you. Then, determine your pipe size. You can do this by performing a simple string test. To do this, wrap a piece of string around your main water service line then measure the length of the string. Use the table to convert the string length to pipe size diameter.

string test

Knowing the amount of available water pressure and the size of your main line will allow you to calculate water flow. Water flow is measured in Gallons per Minute (GPM). Use the following chart below to complete the calculation. Water pressure (measured in PSI) is along the top of the graph. Locate the box that coincides with your pressure reading. The vertical boxes along the left side of the chart show different sizes of mainline pipe. Locate the size that corresponds to the string test you performed. You will find your GPM where your PSI rating and your main line measurement intersect.


Bucket Test Method

Water pressure can also be found by performing a bucket test. Simply time how long it takes the unregulated outside faucet to fill the bucket. Then, multiply the size of the bucket used by 60. The result will be your water flow in Gallons per Minute or GPM. For example, if you filled a 5 gallon bucket up in 30 seconds you would take 5 gal. / 30 sec. *60 = 10 GPM. This would equate a 10 Gallon per Minute water flow.

Measure and Draw Your Property

house imageThe final step is to measure and draw your property. You can draw your property by hand, but this process is often tedious and time consuming. To solve this, Orbit has created an online tool to make the process a breeze. Simply visit our Sprinkler System Design Tool at where you can import an overhead photo of your property from Google Maps and then trace over the features of your yard. The system will even let you distinguish various areas of your yard, such as lawn, flowerbeds and garden areas, and then you can specify the type of sprinklers you want in these areas.

designerAfter you have entered all the necessary information, the Orbit Sprinkler System Design tool will automatically draw an efficient sprinkler system for your yard.

While the above steps may seem like a lot of work, we can’t emphasize enough how important it is to design your system right. Any errors in this planning phase will affect the design and function of your system.

Used correctly, the Orbit Sprinkler System Designer allows you to plan and design a system that runs optimally with little maintenance.

Check back next week for part two of our series.