A Not-So-Difficult Irrigation Audit Guide

One of the most important factors that go into taking care of your lawn is water. Whether you use a sprinkler, rely on rainfall, or use some other form of irrigation system, the amount of water your lawn receives is something to keep a close eye on. Perhaps one area of your lawn is receiving more water than others, or maybe you don’t really know how to measure the amount water your lawn actually receives. This week on Sod U, we discuss the practice of performing an irrigation audit, how to achieve desirable results for your lawn, and adjustments you may need to make to help deliver the right amount of water to your lawn.

The Audit

Determining the amount of water your irrigation heads are delivering is your first step. The way to do this is to set out cups that will capture the amount of water delivered to each zone during a single irrigation cycle. These cups are not fancy or expensive. They can be anything from an empty tuna can, to the bottom half of a plastic water bottle or soft drink can. Check with your local IFAS station, as they have plastic cups they will give you upon request. It is important to use the same type of cups for your testing to keep your testing practices consistent. Make sure you have enough cups to place in various places within the range of each sprinkler in every irrigation zone of your lawn. Once your cups are in place, turn on your sprinkler system and let it run for its typical amount of time. After the zone has finished running, measure the amount of water captured in the various cups to see if they are roughly the same. Record the information in that zone and move to the next zone until you have measured the results of your entire lawn.

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The Results

Your target is to end up with a half inch of water in your cups consistently in each zone. One inch of water within the week is enough for your lawn, so half an inch delivered twice a week will give you the inch of water needed. A typical home lawn uses two types of irrigation heads: rotors and sprays. Rotor heads rotate in a circle as they deliver water whereas spray heads remain stationary and are typically used in smaller areas. These heads differ in gpm (gallons per minute) of water they deliver, so they must be set accordingly as to the amount of time they run. Check each of your zones to ensure the heads are all the same, as spray heads and rotor heads and rotor heads should never be used together in one zone.

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Adjustments

Now you are ready to make the adjustments necessary to achieve delivering the proper amount of water to each irrigation zone. If more water is needed, here are two ways to make that happen: invest in larger nozzles, or increase the time the zone runs. If you can add more time to the zone and not upset any kind of HOA watering requirements, then do so. This is the easiest way to increase the water needed and does not cost anything. If increasing the time is an issue, you will need to change out the existing nozzles to larger ones. Obviously, if you catch more water than 0.5 inch and need to reduce the water delivered, decrease the time the zone runs or use a smaller nozzle.

Helpful Tip

Over-watering is a huge problem and can lead to disease pressures. If you suspect a disease or fungus in your lawn, read our Lawn Disease Control blog for useful tips. Consider turning off your irrigation clock during the rainy season and then again in the winter. During this time, let your grass tell you when it is thirsty. Look for grass leaves to fold inward. This indicates your grass is needing water and you can turn your system on for a week.

As previously mentioned, an irrigation audit can be performed with anything from an empty tuna can, to the bottom half of a plastic water bottle or soft drink can. However, there are a few products you can use that may help you accurately measure the exact amount of water being delivered into one place. See some of our recommended products below:

To read more about irrigation, when and how often to water, or to learn more about useful tools that might help you measure your lawn’s water holding capacity, check out our Lawn Irrigation Guide. If you’re interested in reading more about setting up an irrigation system or want to learn more about the different types of systems, click here: All Things Irrigation.