This type of audit you don’t need to be afraid of, even if you do get soaked. A lawn sprinkler audit done annually is one of the best home improvement investments you can make so your lawn stays lush and your water bills stay low.
“Nationwide,” according to the U.S. Environmental Protection Agency, “landscape irrigation is estimated to account for nearly one-third of all residential water use, totaling nearly 9 billion gallons per day.”
And as much as 50 percent of that irrigation may be going to waste, due to inefficient or improper watering, the EPA says.
When to audit
Auditing your irrigation system to make sure it’s working well can be done anytime weather permits, but early spring is an especially good time since it comes before your lawn’s growing season. As far as what part of the day, early morning is the best time to test your sprinkler system. The sun isn’t yet at its peak, so you won’t lose much water to evaporation, and water pressures are high.
Big-picture considerations for a sprinkler system
There is more to a lawn irrigation audit than checking hoses and sprinkler heads for leaks. First, experts advise, take a step back and figure out what you have and what you need.
Your lawn’s size in square feet and shape will heavily influence your watering decisions. If the area is compact and rectangular, a simple hose-end oscillating sprinkler may be all that is needed.
There are three main types of soil, each with different watering requirements:
- Clay soils: Require less watering because they hold the most water. Because water seeps slowly into clay soils, water at low rates over a longer period.
- Sandy soils: Water passes through sandy soils quickly., so water more frequently but for shorter periods of time.
- Loam soils: These lie in-between sandy and clay soils in their moisture retention, so take a medium course — moderate watering over a moderate period.
Grass types influence watering needs
Grasses vary greatly in their drought tolerance. The more tolerant they are, the less water they will need
|Drought tolerance of common types of grass|
|Warm-season grasses||Cool-season grasses|
|Good||Bermudagrass, Zoysia japonica, Seashore paspalum||Tall fescue|
|Fair||St. Augustinegrass, Centipedegrass, Bahiagrass||Kentucky bluegrass|
|Poor||Zoysia matrella||Bentgrass, rough bluegrass, perennial ryegrass|
|Sources: Texas A&M University Extension Service, Cornell University Sports Field Management|
Conducting your lawn sprinkler audit
The goal is to achieve lawn irrigation to a depth of six inches. Here is how you figure out how much to water, and how to adjust your sprinkler system to achieve that six-inch depth.
- Place cups or cans at various spots around your lawn. There are specialized “catch cans” designed for the job that you can purchase online, from some county extension service offices or water utilities. Shallow-sided cans, such as tuna or cat food cans, or even milk cartons with their tops cut off, do best for this test.
- Evaluate your spray patterns and adjust and replace your sprinkler heads and relocate other sprinkler devices until the cans are catching a relatively even amount of water. Fix any cracked or clogged sprinkler heads.
- Water for a half hour.
- Measure the water in each watering can, and average them.
- Take soil probe or a spade and note how deeply the lawn was watered.
From the two figures — the average amount of water and the depth of saturation — you should be able to figure out your desired watering time.
For example, if a half hour of watering filled your cans to an average of 0.5 inches, and moistened the soil to 3 inches, you know you’ll need to water for an hour to get the water to soak 6 inches down.
If you also have a drip irrigation system, check it as well. There may be some wear and tear that calls for the replacement of parts. This would be a good time to flush out the system, as the No. 1 problem with drip irrigation systems is an accumulation of dirt that causes clogs.
Typical homeowner water sprinklers and irrigation systems
A simple and economical water sprinkler installed at the hose end. The pattern of spray is determined by the pattern of holes, the volume is controlled at the faucet. To change the area of coverage, you drag it around the lawn.
Gear drive sprinkler
This type of heavy-duty sprinkler is often found on golf courses or other large areas of grass where both large volume and precision in watering is needed. Their gear-driven motion usually has multiple flow controls that let you adjust the distance the water is sprayed, and the angle and force of the spray.
Hose-end spray nozzles
These simple devices are a best seller. Inexpensive and versatile, they can be made of plastic or brass, and are often controlled by a handle that turns the water on and off. The volume and pattern of spray is controlled by either twisting the nozzle or via a dial attached to the nozzle.
With an impact (sometimes called impulse or pulsating) sprinkler, the spraying nozzle is rotated by the pressure of the water from the hose. Made in both plastic and brass; the brass impact sprinkler is more expensive but more durable. Some models are attached to the ground via a spike, others are elevated to become a tripod sprinkler. Control collars limit the travel of the head, and a rocking arm repeatedly inserts itself into the stream of water to both drive the head and create an additional spray stream. The pulsating sprinkler was invented in 1933 and marketed under the Rain Bird brand name.
In-ground water sprinkler
In-ground water and garden sprinkler systems use a series of sprinkler heads installed at fixed locations in the yard. When properly maintained, in-ground systems give complete and efficient coverage. Many feature pop-up sprinkler heads. Ideally, your in-ground sprinkler system should be designed with “hydrozone separation” in mind. That is the concept of grouping plants together that have the same water consumption habits. Your grass would be on one zone, your thirsty ornamental plants on a second and drought-resistant plants on a third. That way you can adjust your spray time and pattern so that all the plants in the zone are happy.
At its simplest, the oscillating sprinkler has a metal or plastic bar with holes drilled in it. Water comes out the holes as the bar rocks back and forth and sprinkles the lawn with a gentle spray. You control the size of the area at the source, by adjusting the water volume at the faucet. Great for relatively small, rectangular yards. More-advanced models such as the turbo oscillating sprinkler allow greater control of the watering pattern and spray volume.
As its name implies, traveling sprinklers have wheels that let them move through the yard, dragging the hose behind them. Excellent for irregularly shaped lawns.
Other irrigation equipment to consider
Flow control meter
This device is installed between the faucet and your hose, and monitor the amount of water that goes through. Some feature an automatic shutoff control that prevents wasteful overwatering.
An automatic timer shuts off the water at a designated time. Some models are hose-end, others are built into in-ground sprinkler systems to control the timing of each section of the irrigation system.
Smart irrigation controller
Your phone is now smart, and watches, thermostats and doors, too. So it’s no surprise that sprinkler controllers have climbed onto the smart bandwagon. Instead of relying on a fixed timer, they use either Wifi or GSM cellular connectivity to pick up plant data and weather forecasts. If rain is forecast or the soil is still damp, they will forgo a scheduled watering.
Some water utilities offer free sprinkler audits
Your water utility has an interest in preserving water, so much so that many public and private services offer sprinkler evaluations at no or low cost.
Free programs are offered in many cities and counties across the United States, including
In Colorado: A consortium of 30 water districts, including those serving Denver, Boulder and Fort Collins.
In Utah: Counties around and including Salt Lake.