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Add a Zone Irrigation
There are several reasons that you may be interested in adding another zone to sprinkler system.
You may have been working with a low budget when your sprinkler system was originally installed, so you only had irrigation installed in the front and side yards to save money. And now you have saved up more cash and don’t want to hand water your backyard with a hose anymore.
Or maybe you planted new vegetable or flower gardens in your backyard and you want to tap into your existing irrigation system to add sprinkler heads to water these new areas automatically.
You could have cleared some overgrown brush on the edge of your property and are planting new plants or grass where the brush was before you removed it.
Regardless of the reason you need to expand your sprinkler system, some considerations need to be made.
Adding a Sprinkler Zone
If you are going to add new sprinkler zone you will need to consider whether or not your existing sprinkler controller can handle the new stations.
Some irrigation controllers are fixed in terms of their total capacity, or possible number of zones. If your sprinkler controller capacity is fixed and you are already using all of the possible station slots, you will need to replace or upgrade your irrigation controller.
Many modern sprinkler controller models are modular. This means that the irrigation controller comes with a certain number of zones (usually three or four) included, and if more stations are needed, additional optional modules can be added, which will expand the capacity. So, if your controller is modular, you or your irrigation company can simply add a new module for your new zones, rather than needing to replace the entire sprinkler controller.
Another consideration is your sprinkler wire.
Did your irrigation system installer leave you with enough spare wires? If not, you will need to either run a new wire from your existing controller, or add a second controller in the new area. This could be a battery powered controller if you have no receptacles in the area, but battery controllers are very rarely the preferred solution.
Battery controllers are less reliable than a wired controller. Plus, you need to replace the batteries regularly. So for several reasons battery powered sprinkler controllers are more maintenance intensive than wired models.
Once you have determined that your irrigation controller can handle the additional zone(s) and the sprinkler system contractor that installed your irrigation system left you with sufficient wires to expand your sprinkler system, you are ready to get on with it.
Add Irrigation Zone
A new valve will need to be installed in an underground sprinkler valve box. The new sprinkler valve will connect to the irrigation mainline pipe with a tee pipe fitting and glue. The new irrigation valve will need to be wired into the sprinkler wire.
From there, a new pipe will be run.
If you are installing drip irrigation, you may need a pressure reducing valve. From there, the drip pipes can be run around the plants, and held in place with drip staples.
Make sure you are using the appropriate number of sprinkler heads. You do not want too many or too few sprinklers. So, the next step is to determine how many sprinkler heads will be needed. Or what length of drip lines, if you are opting for drip irrigation.
How many sprinklers can you run off of one zone?
The ideal sprinkler zone design maximizes the number of sprinkler heads that are able to be installed with the appropriate amount of water flow and pressure. If too many sprinkler heads are installed on a zone or station, the sprinkler heads will barely raise up and will just limply dribble water out without accomplishing anything.
And if too few sprinkler heads are installed, you will end up spending more money than is necessary to have more than one zone. So, installing either too few or too many sprinkler heads on a station or zone will cost you more money in the long term.
The following steps are likely not necessary if your irrigation contractors do great work. Assuming they know what they are doing, your new zone(s) should be well designed. But if you would like to make sure the appropriate number of sprinkler heads are being used, here are a couple of ways to find out.
To get a general idea of what the new sprinkler zones are capable of, you can look at how many sprinkler heads your existing zones are using, and install a similar number. But running pressure and flow tests will give you a better idea of what capability you have with the new zones.
In order to run a pressure test, you can get yourself a threaded pressure gauge.
And screw it onto one of your backflow preventer’s test cocks.
This will only be possible if you have an RPZ, PVB, double check, or other backflow preventer that has test cocks.
If you do not know what kind of backflow preventer you have, you can check out this article.
Once you have screwed your pressure gauge onto your backflow valve’s test cock, you would then turn the test cock valve 90° with a flathead screwdriver to get the water flowing into the pressure gauge.
After noting the pressure reading, you can close the test cock valve by using your flathead screwdriver to turn the test cock valve 90° to close it.
Then you can remove your pressure gauge.
If your backflow preventer does not have test cocks, you can likely use your sprinkler blow out point to take the pressure reading.
In order to use your blow out point, you will first need to turn off the sprinkler shut off valve.
If you are not familiar with how to accomplish this, you can check out this article for assistance.
You may need to get some threaded pipe fittings called reducer bushings if the pressure gauge’s threading is not the same size as the backflow preventer test cock or the blow out point.
Most sprinkler blow out points are either 1” or ¾”. And a pressure gauge’s threaded fittings are likely to be smaller than that.
Once you have turned off your sprinkler shut off valve, you would unscrew your sprinkler blow out point cap using Channel Locks if the cap is threaded on more than hand tight.
Next, you would thread the reducer bushings and the pressure gauge onto the sprinkler blow out point.
And then the water would be turned back on.
After noting the pressure reading, the sprinkler shut off valve needs to be turned back off.
Then, you can remove the pressure gauge, reducer bushings, and thread the cap back onto the sprinkler blow out point cap.
Once the sprinkler blow out point cap is securely back on, the water can be turned back on.
So, now you hopefully have your sprinkler system’s pressure. Next, is the water flow. The easiest way to get your home’s water flow is often to get yourself a five gallon bucket.
You then open the stopwatch app on your smart phone.
Next, you turn the hose bib on full blast and start the stopwatch to see how long it takes for the 5 gallon bucket to be filled.
If it takes one minute to fill the five gallon bucket, that would mean that you are working with roughly five gallons per minute of water flow.
If it takes 30 seconds to fill up the five gallon bucket, then you know you are dealing with roughly 10 gallons per minute of water flow.
Unless you are on a well that does not have a very powerful pump, you likely have closer to ten gallons per minute or more.
If you have about ten gallons per minute of water flow, that would mean that (depending on what size nozzles you are using) you could install about five rotary sprinkler heads, or about ten fixed spray sprinkler heads; as standard rotary sprinkler heads use roughly two gallons per minute and standard fixed spray sprinkler heads use around one gallon per minute.
Adding Zones to Irrigation System
If you are hiring a skilled irrigation company to perform the sprinkler system expansion, they will likely design the new zones properly, but now you have some options if you would like to make sure they are designing the new zones appropriately.
Once the correct number of possible sprinkler heads have been determined, it will be time for your sprinkler company to get to work.
Add New Zone to Sprinkler System
Before they begin the work they will likely mark the locations of the new sprinkler heads so that you can visualize where they will go. Some companies may offer drawings with the location of the new sprinkler heads and valve, but they may charge more for this, as drawings should not be necessary to complete the work.
Once the new sprinkler heads or drip lines have been installed, your sprinkler system contractor should perform a walkthrough where they turn on the new station and demonstrate that everything is functioning properly.
Add Sprinkler Zone Cost
The cost to add a sprinkler zone can vary tremendously, depending on a number of factors, including:
- The cost of living where you live. Do you live in Manhattan or Beverly Hills? Or do you live in Oklahoma City or Harlingen, Texas? Because in high cost of living cities everything costs significantly more than in lower cost of living areas.
- The quality of the irrigation company that you are hiring. If you are hiring a reputable company that is licensed and bonded, and has skilled and experienced technicians, adding a zone can cost significantly more than if you are just hiring a random, inexperienced person with a truck who is learning as they go.
- The quality of the parts that you are using. Cheap parts and less skilled labor cost less up front, but will likely cost you more in the long run for maintenance when the sprinkler system components start to break down and cause problems prematurely.
- The distance away from the closest needed irrigation components. If you are trying to add a sprinkler zone 50 or 100 yards away from the closest zone, it is going to cost considerably more than if the nearest valve box is a few feet away. This is because in order to add a zone, the nearest valve box or mainline needs to be dug up and tapped into. The further away it is, the more work it will take to do the trenching, and the more parts (wire and pipe) will need to be used.
- Whether or not your irrigation system has spare wire. If your sprinkler system does not have any functioning spare wires, adding a new sprinkler zone will cost more because you will need to run a new wire from your sprinkler controller to the area where the new zone valve will be installed. You can add a battery controller instead of running a new wire, but as previously mentioned, battery controllers are not the most ideal option. Among other issues, this is because you need to program an additional controller and replace batteries fairly often.
- Does your controller have spare slots for an additional zone? If not, you will need to replace your controller with a larger model that has more capacity. Obviously, this will add to the cost.
As a result of all of these issues, there is going to be considerable variability in the pricing. That said, adding a sprinkler zone may cost anywhere from $500-$1,500. It is possible that it could cost more or less depending on the factors listed above, but this is a general idea of price.
So, now you have some additional details about how to add a zone to sprinkler system. You can now decide if you would like to pursue this option. The next step is to get in touch with a quality, experienced irrigation company and ask them to take a look and see what options you have for your specific sprinkler system.