Do you suffer from an over-active sprinkler? You’re not alone. Over watering of lawns and landscapes is the most common cause of water waste. It not only runs up utility bills, but can cause other problems including:
- Plant diseases such as root rot.
- Run-off from your yard, which may contribute to the pollution of streams and lakes.
- More frequent mowing & pruning from rapid plant growth.
- Excessive “green waste,” which has become a costly waste disposal problem for cities and counties.
This section provides advice on how to water your yard to optimize plant health and minimize waste.
There are two basic ways to water: manually with hoses and sprinklers, or automatically with clock-driven in-ground irrigation.
Households with automatic systems on average use twice as much water outdoors as households that water manually. The reasons for this are discussed further below, but here are some common tips for making both manual watering and automatic irrigation more efficient:
- Never water if the soil is wet. This is the first basic rule of irrigation. If the soil is dry to a depth of one inch, it’s okay to water.
- Water infrequently but deeply. When your landscape is dry, water it well, soaking the soil to a depth of 4-6 inches. This will promote deep root growth, making your lawn and other plants more drought tolerant.
- Water based on weather conditions. During hot, dry, and windy conditions, plants use up water more rapidly and will require additional water. In the cooler fall, winter and spring months your landscape may not need any irrigation.
- Know your plants. Get to know their water needs and the signs of moisture stress. Wilting can be a good indicator for high or medium water using plants. Turf grass will take on a grayish-green color and the blades may fold. But plants will also wilt if their roots die from over watering. Any number of other diseases and even insect damage can also cause wilting. Some drought tolerant plants fold their leaves on hot afternoons to conserve water, which can be mistaken for wilting. It’s best to check soil moisture before watering.
- Water areas in the shade about 30 percent less than sunny areas. Shade creates a “microclimate” of cooler temperatures and lower evaporation, so plants need less water.
- Water in early morning or after the sun has gone down to reduce evaporation losses.
- “Cycle” your sprinklers. Sprinklers usually apply water at a faster rate than soil can absorb it. Run your sprinklers for 2 or 3 short cycles instead of one long cycle on the days that you water to ensure that the water soaks into the ground, rather than running off your yard. This is especially important if you have dense or clayey soils that absorb water slowly.
- Don’t use sprinklers on windy days. This results in uneven watering and overspray onto sidewalks and pavement. If you live in a windy climate, consider installing drip irrigation for plantings and low angle sprinkler heads for lawn, which keep water throw near the ground where it resists blowing away.
- Apply a three inch layer of mulch or compost around plants to reduce evaporation, promote plant growth, and reduce weeds. Keep mulch a few inches away from tree trunks to prevent rot.
There are some additional things you can do to make manual watering easier and more efficient:
- Always use a spray nozzle with a shut off valve when hand watering. A watering wand with a shut-off in the handle is a good choice.
- Use soaker hoses and drip irrigation to water flower beds, vegetable gardens, shrubs and trees. Both of these irrigation methods efficiently deliver water to the root zones of plants and can be connected to an ordinary hose.
- Attach a timer valve to your outdoor faucet. This will allow you to run your sprinklers or soaker hoses for a pre-set amount of time and they will automatically shut off.
How much water should I use to irrigate my yard?
You can get an estimate of the monthly water needs of your yard by using Weather ET Data. The Calculator estimates a “water budget” for your yard based on your climate, time of year and the size of your lawn and landscaped areas. Compare the water budget to your actual water bill to see if you could be saving water and money.
Automatic sprinkler systems on average account for 50% of home water use. If you’re looking for a way to save water it makes sense to focus on the big uses, and it doesn’t get any bigger than the sprinkler system. The typical home irrigation system is only about 40-50% efficient, meaning half of the water applied to the landscape is wasted, not benefiting the plants.
Obviously, there is room for improvement! Many water utilities offer free irrigation system audits as a service to their customers. It’s a great way to learn how to water your landscape more efficiently.
The keys to efficient automatic irrigation are 1) scheduling your irrigation controller to apply the right amount of water in the right way and 2) proper maintenance of your irrigation system. Helpful advice on irrigation scheduling and system maintenance is provided below:
The Irrigation Controller (a.k.a. Irrigation Timer or Clock)
The controller is the heart of your irrigation system. It works by turning on and off the different valves for the various irrigation zones in your yard. Each zone can be scheduled to irrigate for a specific amount of time according to the water needs of the plants in that zone.
For example, the irrigation zone for a sunny lawn area should be set to water more than a zone for shady lawn or for drought tolerant shrubs. If your landscape and irrigation system are designed properly, your plants should be arranged into groups based on their water needs (called “hydrozones”) and your irrigation system will have separate irrigation zones for each of these plant groupings.
Modern home irrigation controllers are capable of handling 6-12 irrigation zones. Each can be programmed to water on its own schedule.
Remember, you are the brains behind your controller because you set the irrigation schedule for each zone. Properly setting irrigation run times is one of the most important things you can do for landscape health and water savings. The basic concept is simple: each irrigation zone should be set according to the water needs of the plant grouping.
Evaluate the water needs of each irrigation zone
Irrigation scheduling begins with an examination of the plants to be watered, sun exposure, and the soil type. Some general guidelines are presented below (ask your local university cooperative extension office or library for a regional plant guide for more specific information):
- Turf grasses, annual flowers and vegetables are usually high water using plants. Turf grass is shallow rooted and fast growing and requires more frequent irrigation. Cool season grasses such as Kentucky blue grass need considerably more water than warm season grass varieties such as centipede, bermuda or buffalo grass.
- Ornamental shrubs and ground covers may use 40% to 60% less water than turf or annual flower beds.
- Regionally adapted plants are often low water using plants, and may use 60-90% less water than high water use plants.
- Drought resistant plants, including many regionally adapted and native plants, may thrive on minimal or no supplemental water. Many of these plants can survive strictly on seasonal rainfall once they are established.
- Newly planted plants need to be watered more frequently until their root systems are established, usually 2 to 3 years, after which irrigation should be scaled back.
- Potted or container plants dry out more quickly than those in the ground and therefore require more frequent watering.
- Plants in full sun areas of your yard often require about 30% more water than shady areas.
- Plants in sandy soils require shorter more frequent irrigation than clay or loam soils because of the lower water holding capacity of sandy soil.
In the example above the Water Budget Calculator was used to estimate the monthly water requirements for two yards of the same size in St Louis, Missouri. The graph illustrates the seasonal rise and fall in plant water demands, but also shows the importance of plant types in your landscape.
The Traditional Landscape is composed of 2/3 turf & 1/3 shrub areas. The Water Wise Landscape is 1/3 turf & 2/3 locally adapted trees, shrubs and groundcovers, and saves 28,000 gallons of water over one irrigation season.
Water deeply and infrequently
Once you have evaluated the water needs of each irrigation zone in your yard, how should you schedule the controller to apply the water? Everyday? Once a week? The answer is to water deeply and infrequently, allowing the soil to dry in between irrigations. This will promote deep root growth and healthy plants.
On days you water, cycle your sprinklers on and off so that the water has time to soak into the ground.
Sprinklers usually apply water at a rate faster than the soil can absorb it. This causes wasteful runoff and is a particular problem when irrigating on slopes or irrigating heavy clay soils. Fortunately, solving this problem is easy. Most modern irrigation controllers offer the option of 2 or 3 irrigation start times per day.
Here’s an example: Instead of scheduling your system to water once for 15 minutes, use the multiple start time feature and set up three start times of 5 minutes each. The rest between start times will allow the water to absorb deeply into the root zone and should eliminate run-off.
Note: multiple start times are not recommended for drip irrigation systems because drip systems use very low volume emitters. A hypothetical watering schedule using multiple start times is shown below.
|Irrigation Zone||Plant Water Use||Sprinkler Type||# of Starts||Minutes Per Start||Days Per Week||Total Minutes Per Week|
|1 Lawn – full sun||High||Spray||3||6||MWF||54|
|2 Lawn – partial shade||Medium||Spray||3||4||MWF||36|
|5 Annual Flower Bed||High||Drip||1||15||MWF||45|
Adjust Irrigation According to the Weather and Seasons
Plants require considerably more water in hot dry months and may require little or no irrigation in the cooler months. Cut back on irrigation during cooler months and turn off your system in the winter. Newer sprinkler controllers have a percent increase/decrease feature.
This feature enables you to reduce or increase watering across your entire system by a fixed percentage. This feature makes it much easier to adjust your clock for seasonal changes.
The weather can change on a daily basis. Don’t forget to turn off your irrigation system if it’s expected to rain and keep it off for several days until the soil dries out. Some sprinkler controllers have a convenient rain pause button that enables you to postpone irrigation for a day or more.
Relatively inexpensive rain or soil moisture shut-off devices may be added to irrigation controllers which automatically turn off your irrigation system if it is either raining or the soil is wet.
Major advances in controller technology have occurred in recent years. New “Smart Controllers,” also known as Weather Based or ET Irrigation Controllers, schedule irrigation according to actual water needs of plants by using information such as weather, climate, plant type and the soil type of your landscape.
Smart controllers take much of the guess work out of programming a traditional controller and have been shown to save about 20% on irrigation water use. Smart controllers and rain shutoff devices are discussed further under New Irrigation Technology below.
During a severe drought your water supplier may ask you to cut back on watering your landscape. For advice on cutting back in times of drought while preserving landscape health, see Drought Response.
Irrigation System Maintenance
We have all seen misaligned sprinklers watering the pavement and broken sprinkler heads spouting in the air like geysers. Regular system maintenance is critical to efficient irrigation and a healthy landscape. Observe your system in operation frequently during the irrigation season.
Turn on each irrigation zone individually and see whether water is reaching all the areas it’s supposed to and not unintended surfaces such as driveways. Tips for fixing common problems and routine maintenance are presented below (see Types of Irrigation Systems for a description of the various irrigation system parts).
Misaligned Heads and Emitters
While the system is running, twist the nozzle to change the direction of coverage. Some pop-up heads have a radius adjustment screw or the nozzle can be twisted to change the radius of the spray pattern. For drip irrigation, check to see that the emitters are applying water to the root zone of the plants.
Low Flow or Misting Heads
Most pop-up spray heads have an adjustment screw on the top of the sprinkler nozzle to adjust flow. Rotary sprinkler heads have a diffuser screw to adjust the distance of the throw. Turn clockwise to decrease flow and counterclockwise to increase flow.
If the flow is still not adequate, your water pressure may be too low or the head may be clogged. Open the control valve fully for that irrigation zone to increase pressure. If heads are misting, the water pressure is too high and the control valve should be turned down until a proper spray pattern is achieved.
Alternatively, a pressure regulator can be installed to reduce pressure. If pressure is too low, your system may have been designed improperly and there are too many sprinkler heads or emitters on the irrigation zone, or you may have a system leak.
Heads and nozzles are relatively inexpensive. If they’re clogged, broken, or stuck, you can replace them quite easily. Sprinkler heads are usually threaded and screw into a connection buried in the ground as part of the pipe network. To replace a broken head, first dig out all the dirt around it.
Firmly hold the riser pipe under the sprinkler head with one hand while unscrewing the sprinkler head with your other hand. Avoid getting dirt into the riser. Take the broken head with you when you buy a new one to make sure you get one that matches with the same spray pattern and application rate.
Clogged Heads and Emitters
Debris in the pipes can clog sprinkler heads resulting in uneven coverage. To prevent this you should flush your system once a year. Remove the nozzles and filters from all the sprinkler heads and turn on the water for a few minutes to flush the system.
Rinse the filter and clean the nozzles. Use an old tooth brush, tooth pick or wire to remove any stuck debris. Calcium buildup can be removed using one of the many calcium remover products available for kitchen use.
If after flushing the system you still have some nozzles that aren’t working properly it’s best to replace them. On some sprinklers the nozzles can’t be removed so you have to remove the entire sprinkler head body and replace it with a temporary riser to flush the system.
See Head Replacement instructions above for removing the head, then screw in a temporary riser for the flushing procedure. For routine annual flushing, you may wish to do this only on the last sprinkler head in the circuit since it requires additional effort.
For drip irrigation remove the end closure from the poly-pipe supply line(s) and flush the line until the water runs clean. Clean or flush the drip system filter frequently during the irrigation season.
Clean or replace clogged drip emitters and micro sprayers. If your emitters are working up to a point in your system and then stop, you may have a pinch or a kink in the poly-pipe supply line. Simply locate the pinch or kink and straightening the line.
Sometimes pop-up sprinkler heads will stick in the up position. If you already use spring loaded pop-ups the problem is most likely caused by sand or debris stuck in the wiper seal.
Unscrew the spray head cover to clean whatever is stuck in the wiper seal. If this doesn’t correct the problem buy a new head with the same application rate and pattern. Choose a pop-up heads with a height of at least 4″ to clear the grass.
Growing grass or shrubs can block the spray pattern of sprinkler heads resulting in poor coverage. Keep lawn mowed and shrubs pruned to prevent this. As your garden grows, this may no longer work, in which case you can install taller risers for the sprinkler heads, or replace short pop-up heads with 4 or 6 inch pop-up heads.
New adjustable-extendable risers are available that make it easy to twist or pull a head into an optimal irrigation position (see Head Replacement instructions above for installing a new riser). If you are using sprinkler heads to irrigate shrubs and beds strongly consider changing to more efficient Drip Irrigation.
Leak Detection and Repair
System pipes and joints may develop leaks or an automatic control valve may fail to shut completely. Indications of leakage include an unexplained rise in your water bill, poor system performance, dry spots, soggy areas in your yard, overgrown areas of turf, erosion and/or subsidence.
For drip irrigation the supply poly-pipe may be damaged by foot traffic or by gnawing and chewing animals. Leaks in drip irrigation systems are easy to detect if the supply lines are only covered with mulch. Visually inspect the drip lines while the system is running. Tighten clamps at leaking joints. Small line leaks can be repaired with plugs.
Tracking down a leak in your sprinkler system is a bit more involved. (The Meter is usually located in the front yard in a ground box near the street or in a basement).
If the meter is moving, you’ve got a leak. To check for a slow leak, write down the meter reading and wait twenty minutes or so to see if there is any movement on the meter. (You can also use your water meter to measure the amount of water applied to your landscape and to track water use.)
If you have a leak, it’s probably in one of the control valves. To test for leaks beyond the control valves in the actual system piping you will have to cap off the sprinkler heads, then run each irrigation zone one at a time, checking your water meter for movement.
If the meter is indicating a leak, look for water appearing at the surface to locate the leak. Repeat for each irrigation zone. Locating a slow leak may require the services of a professional.
To repair a leak in the sprinkler supply line, cut out the damaged section of PVC pipe and replacing it with a new section of pipe or use a repair coupling. Leaking joints should be cut out and completely replaced.
You can try fixing leaky Control Valves by opening and closing them rapidly with the water running to dislodge any debris. If that doesn’t work you may have to take the valve apart and clean it. Cracked or damaged control valves should be replaced.
Winter Shut-Down Procedures
In places where the temperature drops below 32° F, winterization of your irrigation system is a must to avoid cracked pipes and broken heads and other system damage. Fortunately winterizing your irrigation system is simple:
- Turn off the water to the irrigation system at main valve.
- Set the automatic irrigation controller to the “rain” setting.
- Turn on each of the valves to release pressure in the pipes.
- Drain all of the water out of any irrigation components that might freeze (you may have to pump air into the pipes to remove all the water).
These procedures will vary depending upon the climate. Click here (link to Jess Stryker’s Irrigation Tutorials) for a detailed explanation of these tasks.
Spring Start-Up Procedures
Always flush out and tune up your system at the start of the irrigation season. During the winter many small critters take up residence in your sprinklers, emitters, tubes, and pipes.
See Clogged Heads and Emitters above for instructions on flushing and cleaning the system. After flushing, run the system and look for clogged emitters or nozzles. Clean or replace them with new ones of the same kind. Adjust misaligned or obstructed heads.
Check for leaking valves. Often the flexible seals dry out over the winter and leak when the water is turned back on. Bring the old o-rings to the store when you buy new ones to be sure that you are purchasing the correct size.
Finally, check the controller for proper run times for each station. If it has a back-up battery, replace it with a fresh ALKALINE battery. The battery on some controllers is located behind a face plate where you can’t see it, so if you don’t see a battery, remove the wiring compartment cover.
Most new controllers now come with non-volatile program memory and don’t need batteries.
New Irrigation Technologies
New irrigation devices and technologies are being developed all the time to deliver water more efficiently. Depending on the age and condition of your system you may wish to upgrade with the following technologies.
New Irrigation Technologies
Existing systems can be upgraded with new technologies that can significantly improve efficiency and save water.
- Install a “smart” irrigation controller, which automatically adjusts irrigation according to climate and plant water needs.
- Use drip irrigation to water trees, shrubs and garden beds. Drip applies water directly to the root zone at a much lower rate than overhead sprinklers.
- Install an automatic rain shutoff device or soil moisture sensor to stop irrigation when it is not required (not needed if you install a weather-based irrigation controller).
- Replace spray heads with new rotary sprinklers. New rotary heads can improve efficiently by 30%.
- Consider rain harvesting and grey water irrigation as an alternative source of water. Rain Harvesting & Grey Water Pages
These technologies are discussed in greater detail below.
Smart Irrigation Controllers
Imagine your sprinkler system could automatically adjust its program in response to changes in the weather to deliver the right amount of water to each plant zone. During hot and dry periods, your system would water more frequently and for longer periods of time. After a heavy rain, your system would not resume irrigation until needed.
Well now you don’t have to imagine! Several companies now manufacture irrigation controllers that apply water based on the evapotranspiration (ET) rate. ET is a measure of the amount of water required to maximize plant growth given the prevailing temperature, precipitation, cloud cover, etc.
Smart controllers have been shown to reduce water use by more than 20%, while maintaining or improving landscape health. Smart controllers are now becoming standard equipment for new irrigation systems and may be cost-effective for retrofitting existing systems depending on landscape size and water use.
Smart controllers use a variety of technologies to schedule irrigation. Some rely on a network of weather stations that transmit daily data (via the web or a pager) to the controller to adjust the irrigation schedule.
Another type has a built in “ET chip” that contains a detailed 20-year history of ET for your region and irrigate based on historical patterns combined with a small temperature sensor. Other smart controllers use on-site rain sensors and/or several soil moisture sensors. The computer schedules the irrigation everyday based on the amount of moisture present in the soil.
Currently, smart controllers cost upwards of $400, but the price is coming down as the technology becomes more widespread. They are relatively easy for the homeowner to install, and some water utilities are offering financial incentives for customers to convert to smart controllers (Check with your water utility). A less expensive retrofit module is now available for some common brands of controllers.
The retrofit module plugs into the existing controller making it a smart controller. Contact your controller manufacturer to see if a retro-fit module is available.
Rain/Moisture Shutoff Devices
Rain and soil moisture shutoff devices automatically turn off your irrigation system if it is either raining or the soil is wet. They do not adjust scheduling like a smart controller, but at least you won’t be irrigating in the rain.
Rain shutoff devices and soil moisture sensors are inexpensive ($25 – $100) and easy to install on just about any sprinkler controller. These products have been proven to save water and money. Some cities and states now require one of these devices to be installed on all new sprinkler systems.
Check with your local water supplier to find out more about requirements in your area. A rain shutoff device works well in conjunction with conscientious irrigation management. See Rain/Moisture Shutoff Devices for additional information.
Drip irrigation (sometimes called micro or low flow irrigation) has undergone many improvements in recent years and is now widely accessible to homeowners. If you are still irrigating shrubs and planting beds with overhead spray heads, it’s time to convert to drip.
Drip irrigation applies water to the root zone of the plant at low pressure and low volume, making efficient use of water. Water is delivered just where plants need it.
Because it is applied slowly on or near the ground, no water should be lost to runoff or evaporation. The amount of water delivered can be controlled by varying the length of time the system runs or the type of emitters.
- Drip irrigation can take the form of emitters, microsprays, or soaker hoses.
- Drip is the preferred method of irrigating trees, shrubs, and vegetable gardens, but it is generally not recommended for continuously rooting ground covers.
- Subsurface drip can be used to irrigate lawn areas. Emitter lines are buried 4 to 8 inches below the lawn or soil surface and are usually spaced 12 to 18 inches apart. Water from the emitter line spreads slowly through the soil to irrigate the lawn or plants.
- Overhead irrigation systems can be converted to drip with retrofit heads (see below).
- Drip systems can be connected to a hose end and manually operated, or be permanently connected to your main water source and operated by an automatic controller.
- Plan enough capacity (emitters) for when your landscape matures. Use the product’s emitter selection chart to determine the flow rate and number of emitters per plant.
- Polyethylene (“poly”) tubing on the surface in areas of heavy foot traffic or children’s play areas can easily be broken, disconnected, or vandalized.
- Dogs, raccoons, gophers, and other animals can chew tubing and emitters. If this is a problem, use rigid pipe (polyvinylchloride or PVC) and protection for emitters.
- Drip irrigation needs to be regularly maintained to check for leaks and clogged heads. Keep your system as simple as possible to lower maintenance. Half inch diameter drip line with the emitters built into the line is highly recommended to minimize maintenance.
Drip irrigation is easy to install, inexpensive compared to overhead sprinkler systems, and can reduce disease problems associated with high levels of moisture on some plants.
Most home improvement stores carry some drip kits, but go to an irrigation supply store for advice and a full line of drip irrigation components.
Converting an Overhead Sprinkler System to Drip Irrigation
You may have an existing overhead sprinkler system irrigating planting beds or shrubs. It is fairly easily to convert an overhead system to an efficient drip system. Drip adapter heads that screw into a traditional overhead sprinkler head are now available.
For it to work correctly, you must convert an entire irrigation zone (i.e. valve circuit). A mixed overhead and drip valve circuit will not irrigate properly because drip operates at a much lower pressure and delivers water at a slower rate. Conversion is relatively easy:
Replace one of the existing pop-up sprinkler heads with a drip adapter.
- Cap off the remainder of the old system.
- Run the new drip line from the drip adapter through the planting beds, making sure the drip emitters are next to the plants to be irrigated.
- Put a cap on the end of the main drip line so you can flush the system once a year or as needed.
Bury the drip line, if you like, or just run it under a layer of mulch. We recommend using a half inch diameter main drip line with the emitters built into the line instead of running secondary emitter Â¼ inch lines off the main line. This will lower maintenance and the cost of the system.
Replace spray heads with new rotary sprinklers
Lawn areas can be irrigated more efficiently with new multi-stream rotary sprinklers. These sprinklers have multiple rotating streams which improves the uniformity of coverage (efficiency) by 30% over conventional spray heads.
If you decide to replace existing spray heads with rotary ones you will have to replace all the heads in that irrigation zone because they have a lower water application rate. Some models allow you to change out just the nozzle in your existing spray head body. Choose nozzles with the appropriate “throw” range and pattern so you get head to head coverage.
Rainwater Harvesting and Greywater Irrigation
Rainwater harvesting gathers rain water that would ordinarily run off your roof or paved surfaces and stores it for later irrigation. Greywater irrigation collects water from sinks, showers and washing machines for use in subsurface irrigation via a separate plumbing system.
See Rainwater Harvesting and Greywater Irrigation for more information.