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How to Save Water with your Irrigation System
Here are detailed instructions for things you can do that will reduce the amount of water your irrigation system uses, with a few extra landscape related tricks for saving water, and a warning regarding water savings and snake oil thrown in at the end of the article.
Water Saving Tips & Ideas for Irrigation Systems
Have your irrigation system audited. Some water providers will conduct an irrigation audit for you either free or at minimal cost. Check with your water provider. If not, your local water provider can likely provide a list of irrigation auditors in your area. You can also look for a Certified Landscape Irrigation Auditor using the An irrigation audit is the first step for those of you who are not "do-it-yourselfers", especially if you get it from an independent auditor who is not also a irrigation contractor or maintenance provider. Regardless of who does the audit, the auditor should carefully examine and test your irrigation system. They should then create a report for you detailing the condition of the system, including a list of recommendations for repairs and improvements. Some auditors also will provide you with an irrigation schedule showing how often and how long you should water during each month of the year. For a full list of things that are usually done in a standard irrigation audit, see the Recommended Audit Guidelines produced by the Irrigation Association. After you have your audit in hand, you can then get quotes from landscapers for performing the repairs and improvements you want done. When hiring an auditor be sure to ask what tests they will perform. Some auditors do not follow the standards set by the Irrigation Association.
Adjust your irrigation controller (timer) run time for seasonal changes in weather once a month. Simply making a monthly change to the irrigation operation times can save more water and money than any other thing you can do. It costs nothing but a few minutes of your time each month. Most controllers even have a % key that makes changing the time quick and reasonably painless. Put a reminder on your calendar so you are reminded each month. Even greater savings come with weekly time adjustments, but monthly will provide the most return in water savings for your time invested. To learn more on the topic, see the Irrigation Scheduling Tutorial.
Run your irrigation system during the morning hours, especially if you use sprinklers. Less water is lost to evaporation when the temperature is cooler, plus in most areas the wind doesn't blow as hard in the mornings. Watering in the evenings can lead to turf and plant disease problems because the water sits on the plants all night, especially in humid climates.
If you irrigate with automatic sprinklers, program your irrigation timer so that it waters in 2-3 short cycles rather than a single long period of time. Allow the water to soak in to the ground between the cycles. Almost all professional irrigation managers water their turf in cycles. For example, if you normally water for 15 minutes, try this; water for 4 minutes, wait 30 minutes or more for it to soak in, then water another 4 minutes, then wait again, then water another 4 minutes. Now you have watered a total of 12 minutes rather than 15. Even with the reduced total watering time, chances are you will see a significant improvement in how good your lawn looks. The reason cycling works so well is that almost all brands and types of sprinklers apply water much faster than it can actually soak into the ground. So after about 5 minutes of running, most of the water begins to build up on top of the soil and then it just runs off into the gutter or to a low spot in the yard. Cycling the irrigation gives the water time to soak into the ground and reduces water run-off, it also will help reduce the wet spots in the lawn where lawn diseases get started.
Give your sprinkler system a tune up. This is another reasonably inexpensive step that gives a good return on your investment. See the Sprinkler System Tune-Up FAQ for instructions on tuning up your sprinkler system.
Make sure tall grass, groundcovers, or shrubs are not blocking or deflecting the water spraying out of the sprinklers. The water from sprinklers heads that pop-up less than 3 inches high is often deflected by tall grass around the sprinkler head. When the water pattern is deflected by tall grass or leaves it results in uneven watering and water waste. With tall grass it may appear that the water spray is forcing it's way through the grass without being deflected, but this is an illusion. You can only see the large, heavier drops of water that are not easily deflected. The smaller droplets that you can't see are being blocked, and that creates uneven watering patterns. The industry standard for lawns is to use sprinkler heads with a pop-up height of 4 inches or more. Turn on the sprinklers right before the next time the lawn is scheduled to be mowed and see if the grass around the heads is blocking the spray. If it is, consider replacing the sprinkler heads with a model that pops up higher. (See the next item down this list, about relocating sprinklers, for tips on flexible risers that allow you to more easily move or replace a sprinkler.)
Shrubs and groundcover that have grown since the sprinkler system was installed may also block the spray of sprinklers. If you don't want to replace or raise the sprinkler heads, trim the shrubs around the heads so that the spray is not blocked. In shrub areas it is not always necessary for the spray to go over the top of the shrubs. In many cases it is OK for the water to spray into the side of the shrubs, especially if the shrubs are 6 feet (2m) or more away from the sprinkler. Shrub roots will often grow out to where the water is. If the shrubs are not wilting and are healthy, then there is no need to change the sprinklers. If you want to really save a lot of water consider changing the sprinklers in shrub areas to a drip system, which will use even less water. More information on drip systems is found farther down in this article.
Relocate sprinklers so that they are between 4 and 6 inches (10-15cm) from the edge of sidewalks, curbs, patios, etc. in lawn areas. In shrub areas they can often be 12 inches (30cm) from the edge, especially with a mature landscape. This will reduce the amount of spray onto the paved surface and will not create a dry area along the edge of the lawn. It will also reduce the amount of damage that trimmers cause to the sprinkler heads. Almost all stores that sell irrigation equipment will have flexible riser pipes made for relocating sprinklers. Using the flexible riser pipe makes relocating the sprinklers much easier, and the flexible pipe allows the sprinklers to move if a car or heavy lawn mower hits them without breaking a pipe or the sprinkler.
Fix leaking valves. Look for water running onto sidewalks or over curbs after the sprinkler system is turned off. If water flows constantly when the sprinkler system is off (often there will be mold or algae growing on the cement or ground) that indicates that a valve is not fully closing. A valve that doesn't close usually is caused by a small grain of sand stuck inside the valve. Clean, or simply replace, the valve. See the FAQ on How to Repair a Irrigation Solenoid Valve.
Fix low head drainage. Do your sprinklers spit and spew air mixed with water for a short period each time they are turned on? This is caused by a phenomena called "low head drainage". Low-head drainage occurs when the sprinkler system has been installed on a sloped area. After the sprinklers are turned off, the water in the pipes drains out through the lowest sprinkler heads and is replaced by air. The water that drains out is wasted, and often flows into the gutter or creates a muddy area around the lowest sprinkler head or drip emitter. Then the air is violently forced out the next time you run the sprinklers. This puts a lot of stress on the sprinklers and pipes. The easiest way to tell if you have this problem is when you turn on the sprinklers. If they spit and spew air when the valve is turned on, then you have low head drainage. See the FAQ on Stopping Low-Head-Drainage & Sprinklers that Spit Air.
Install a Smart controller. A Smart controller does the work of periodically adjusting the sprinkler operating times for you. It changes the run times to reflect the current water needs of the plants. Some water companies will assist in the purchase price of a Smart controller. See the separate FAQ on Smart Controllers for more information about Smart Controllers.
Install a rain switch. A rain switch is a simple rain sensor. When it detects measurable rainfall, it turns off the automatic irrigation valves. You can buy a rain switch almost anywhere irrigation products are sold, most will work with any brand of irrigation controller or timer and any brand of valve. You mount the rain switch on the side of the house, on a pole, or on a fence in a location where water will fall on it but sprinkler water will not hit it. Then you run 2 or 3 wires from the rain switch to the controller. The exact installation instructions vary depending on the brand and model of the rain switch.
Install a filter on your irrigation system. A filter saves water (and money) indirectly. Most valve and sprinkler malfunctions result from contaminants in the water supply. Typically this is small grains of sand, pipe scale, or small fresh-water snails. All of these are common in many public water systems. Installing a simple screen filter at the water source (before the valves) will greatly reduce the frequency of sprinkler system breakdowns and save water. A filter is one addition to your irrigation system that almost always pays for itself within 5 years. The cost of a single valve repair can be much greater than the cost of buying and installing a filter. See the Irrigation Water Filtration Tutorial for more information.
If your irrigation system is located in an area where hard frosts occur make sure you properly winterize it each year before the cold weather hits. See the Winterizing Your Irrigation System tutorial for details.
Switch to newer sprinkler heads. Technology in sprinklers has advanced over the last 20 years and many new sprinklers are more water efficient than the older models. Generally this option is only cost effective if you have a very old sprinkler system, or if your original sprinkler system was poorly designed. Small stream-rotor nozzles that fit onto spray-type sprinkler bodies are being heavily advertised as being more efficient than old style spray heads. A couple of popular brands of these stream rotor nozzles are the Hunter MP Rotator and the Rainbird Rotary Nozzles. A word of warning; while they are indeed more efficient than a standard spray nozzle, it is only a marginal efficiency gain and switching nozzles is probably not cost effective if you have a good sprinkler system. However these rotary nozzles can provide a significant benefit for poorly designed sprinkler systems where spray type heads were spaced too far apart or the pipes are too small. This is because these new rotary nozzles achieve a greater radius than was possible with the old style nozzles while using less water. So if you have a sprinkler system and you give it a tune-up, but it still has dry spots, changing to the stream rotor nozzles may help. Measure how far apart your sprinkler heads are, then select the rotary nozzle that has a radius equal too the distance between sprinklers. So if the sprinklers are 20 feet apart get nozzles that have a 20 foot radius. Replace all of the nozzles, don't try to mix the rotary nozzles on the same system with older nozzles- they are not compatible. It may help, and it may not. You might want to buy the nozzles at a the store with a generous return policy. That way if they don't fix the problem you can return them. Not all spacing problems can be repaired using stream rotor nozzles. You may need to add more sprinklers, or just totally redesign the sprinkler system to fix the dry spots.
Switch to drip irrigation for watering shrubs. Drip irrigation is about 20% more water efficient than sprinklers are. It is easy to install, and reasonably inexpensive. See the Drip Irrigation Design Guidelines for more information.
Do you have an alternate source of irrigation water you could use? Water from creeks, ponds, and shallow wells are all examples. Grey water from roofs and sinks is another source if you have very limited irrigation needs. These are typically not easy solutions. You need to do a lot of research before you do anything. Completely design out the system and make sure you have enough water- and make sure you have a legal right to the water! There are way too many tanks, barrels, and pumps sitting around unused because someone got all excited and bought stuff without researching how much water was really required. Also, digging your own well is not legal in many locations, and requires a government permit to do it pretty much everywhere. If you punch an illegal well out in your yard and it pollutes the aquifer you could lose everything you own paying for the environmental damage. If you dam up a creek and kill some endangered whatever you could find yourself in a lot of trouble. There was a time when you could do whatever you want on your own property, but those days are long gone. Right or not, that is the way it is.
Some sprinkler head models have built-in pressure regulators. The pressure regulators save water by reducing the water pressure at the sprinkler head nozzle. If too much water pressure is present, the sprinklers tend to create too much mist and give uneven coverage resulting in water waste. These built-in pressure regulators are available as an option on many higher quality spray-type sprinklers. Rotor-type sprinklers seldom need pressure regulation, so this feature is not generally available on them. In order for the pressure regulators to work you must have excessive pressure! If you do not have excess pressure, the pressure regulators may actually harm your system's performance. If you are a homeowner and considering retrofitting your sprinkler system using pressure regulating sprinkler heads, turn on the sprinklers and look carefully at the sprinkler head farthest from the valve. If it is not creating a considerable amount of mist, it is unlikely that the pressure regulators will help you save water. So what would be a typical situation where pressure regulating sprinklers would be used? A typical use of pressure regulating sprinkler heads is for a valve circuit on a steep hillside. In this situation the sprinklers at the bottom of the hill will have excessive pressure due to the effect of gravity on the water pressure (take my word for it, this is too complex a topic to cover here.) Using pressure regulating sprinklers on these lower sprinkler heads would cause them to perform better. If the highest sprinkler is not more than 6 feet (2m) higher than the lowest sprinkler on the same valve circuit, pressure regulating sprinklers will probably not be of much help.
Tip: On a typical sprinkler system (that is not on a hillside) you can get almost the same result obtained from switching to pressure regulating sprinkler heads by simply properly adjusting the system. For instructions on how to do this, see the Sprinkler System Tune-Up FAQ. I would strongly suggest that you try properly adjusting the sprinklers first, before you spend a lot of money on pressure regulating sprinkler heads. My experience is that very few sprinkler systems will benefit significantly from the use of the pressure reducing sprinkler heads. If you do have too much water pressure it is usually better to install a single pressure reducer valve on the entire irrigation system, or install pressure reducing valves. Excessive pressure is damaging to the entire sprinkler system, so it is better, and often cheaper, to reduce the pressure in the whole system.
Automated emergency shut-off devices save water by automatically shutting off the water when something in the irrigation system breaks. There are several different types of these devices available. Before we get into specifics, understand that these devices do not save water during ordinary operation of the irrigation system. They only prevent water waste when something breaks. In many cases they simply are not cost effective, so the suitability of these devices must be examined on a case-by-case basis. Automated emergency shut-off devices are often used on irrigation systems where a break or valve failure could cause serious damage (such as an irrigation system watering a steep slope, where a break could cause massive erosion.) They also are used often in locations where a leak might go undetected for days, such as a vacation home or remote location.
The first of these devices is a irrigation controller with the capability of monitoring flows. The controller works in conjunction with a flow sensor and master valve. The master valve is an electric solenoid valve that is installed on the mainline near the water connection point, where it can shut-off all the water flowing to the entire irrigation system. The master valve is typically installed right after the backflow preventer. The flow sensor is installed on the mainline pipe after the master valve. Be sure to follow the manufacturer's directions when installing a flow sensor as it will not work accurately if it is not installed exactly as recommended. The flow sensor is connected by wires (often using special communications cable rather than standard wire) to the irrigation controller. Some controllers use a wireless signal to communicate with the flow sensor. The controller used must be a model that is capable of monitoring the flow sensor and responding to the input from it. Typically this feature is only found on higher-end controllers. If you're interested in this type of system, select the controller first. The controller manufacturer will then have specific recommendations as to the type and model of flow sensor and master valve to use. Follow the manufacturer's recommendations.
Here's how it all works: When water flows into the irrigation system the flow sensor measures the rate of that flow. The controller is set in learning mode, where it monitors the flow sensor output and memorizes how much flow occurs at any given time of the day when everything is working correctly. Once it has a history of correct flows, it then monitors the flow at all times and compares the current flow with what is normal. If it detects an abnormal flow (either too high or too low), it signals the master valve to close. This shuts off water to the entire irrigation system. Most of these controllers will then sound an alarm to alert you. Some will even phone you, email you, or send a text message with an alert. So if a mainline were to break, the flow sensor would show a higher than normal flow, and then the controller would respond by closing the master valve, shutting down the entire system, and alerting you. Most of these controllers will also detect a valve that is broken, as well as any number of other problems.
The second type of shut-off devices are simple mechanical devices that either install under, or are built into, a sprinkler head. These are often called "geyser preventers", a reference to the geyser-like spray of water that occurs when a sprinkler head or nozzle is broken off. These devices are flow activated. If the sprinkler head or nozzle should break off, it will result in a much higher water flow. The higher velocity of this increased flow through the shut-off device causes a valve in the device to close, which shuts off the water supply to the broken sprinkler. Some shut off devices screw directly into the pipe tee under the sprinkler head. The sprinkler riser is then screwed into the shut-off device, and the sprinkler is attached to the riser. (A "riser" is the short length of pipe that connects the sprinkler to the water supply pipe. Most risers are made so that they will bend or twist if the sprinkler is hit or bumped. This ability of the riser to bend or twist greatly reduces how often sprinkler heads break off.) Another type of shut-off devices are built into the bottom of some models of sprinkler heads and are often called "valve-in-stem shut-off devices." The limitations of the built-in devices is that since they are inside the sprinkler they will not work if the entire sprinkler head breaks off, which is a common problem. Keep in mind that neither of these types of mechanical shut-off devices will detect a broken pipe, they only work if the sprinkler breaks. Also be sure to investigate carefully the details on any shut-off device you're considering purchasing. While some devices completely shut off the flow when a break is detected, others simply restrict the flow, but do not completely shut the water off when the sprinkler breaks.
Separate plants into hydro-zones. A hydro-zone is an area where all the plants use more or less the same amount of water and have the same sun and wind exposure. For example, lawn in the sun would be one hydro-zone, the lawn in shaded areas would be another hydro-zone, lawn in the sun on a windy hill-top would be yet another hydro-zone. (The lawn in shade uses less water than the sunny area, the windy hill top uses more water than the sunny area. Wind dries out the grass quickly, similar to how a blow-dryer dries your hair quickly.) The irrigation is separated so that each hydro-zone area is watered by a different valve. This allows you to water each hydro-zone individually for just the right time to apply the water needed by the plants, without over-watering.
Landscape Ideas for Saving Water:
Mow your grass at a higher length (so that it is longer.) While there is some debate about whether this saves much water, scalping the grass off at a low height is definitely not good for the vigor and health of the grass. Longer grass has deeper, stronger roots and is more resistant to disease and drought. Most grass should be mowed to a length of no less than 3 inches. See the next item.
Dethatch and/or aerate your lawn. Lawn aeration helps assure that the water can penetrate easily into the soil, over time the soil surface can become very compacted and water will not easily penetrate it. Aerating also provides air to the roots of the grass, which is necessary for healthy growth. Thatch build-up on the soil surface under the grass blades can actually repel water. How often you need to dethatch or aerate the lawn depends on the type of grass, whether you remove lawn clippings, the type of soil, the climate, and how much you fertilize. (Fertilizer helps feed the bacteria that break down thatch into humus, but too much fertilizer can cause excessive growth and an increase in the amount of thatch.) Dry spots at the higher areas of the lawn are often the first sign you need to dethatch or aerate the lawn. To check take a hose and lightly water the dry area. If the water does not penetrate into the soil quickly you need to either aerate or dethatch, or both.
Reduce the use of fertilizers. Fertilizers encourage rapid growth which results in higher water use. Cut back on fertilizer application amounts to the minimum needed. More frequent application of fertilizer in smaller doses will also help. Try to avoid the green up then yellow off then green up cycle of fertilizer application. Some people find that using an automatic fertilizer dispensing system gives them the green yard they want without wasting fertilizer. Fertilizer injection isn't for everyone, you need to be willing to calibrate the system and keep watch on it. Consider your neighborhood and risks involved, will wind blow the fertilizer filled spray into neighbors yards? Will kids get into the sprinklers and come into contact with the chemicals?
Add a layer of mulch to shrub beds. A 2 or 3 inches deep layer of mulch, such as wood chips, bark, almond hulls, or even decorative rock, reduces water use and also reduces the number of weeds.
Reshape your landscape to use less water. Often a minor change can not only refresh and improve the appearance of your landscape, it can also save water. Look around at your yard layout, especially the size and location of lawns. Can you remove or shrink the size of the lawn areas? Lawn uses much more water than the same size area planted in shrubs or groundcover. Does your lawn go right up to the edge of the house or fences? If it does, you can save water and help your house siding and fences to last longer by reducing the size of the lawn so that it is at least 3 to 4 feet away from fences and walls. Irrigation water spraying on the side of a house or fence can cause all kinds of expensive problems. Try creating a curved meandering edge on the lawn area to mimic the look of a meadow; it gives a much more esthetically pleasing look than a straight edge. Then add a foundation planting of low-growing shrubs with drip irrigation between the lawn and the house or fence. For more design ideas go down to the local hardware or book store and pick up a couple of books on landscape design. Another idea is to visit model homes, often they have good water-efficient landscape layout ideas. When you find something you like, copy it!
Have you looked at the new synthetic lawns and golf greens? Many of them look very good and are very durable, they are much improved from the old fake grass "carpets" of the past. Synthetic grass isn't going to meet the needs of everyone, but they sure save a lot of water compared to a real grass lawn!
How about replacing old high-water using shrubs with shrubs that are less thirsty? Visit a local nursery with knowledgeable staff who can help you select good plants that use less water for your yard. Use of native plants can be particularly water and environmentally friendly, but isn't necessary to get a water saving landscape. You also don't need to go to a "weeds and twigs" look just to save water. While a desert landscape may use almost no water, even a lush-looking landscape that mimics a forest can be designed to use minimal water. If you want a small garden area of high water use plants, locate it in a shady area with protection from wind. Even high-water-use plants will use much less water if they are planted in a shady area where they are protected from strong winds.
Water Savings & Snake Oil
As attention has shifted to saving water, irrigation companies have assigned their marketing departments and sales staff to push for any water saving connection possible that will sell products. “Irrigation specialists” are suddenly everywhere offering services to help you revamp your irrigation system to save water. Unfortunately, along with the many legitimate products and companies a few “snake oil” salesmen are bound to sneak in, trying to turn a quick profit at your expense. In the past few months I have seen a number of questionable claims. Before you fork over your money or sign on the line, ask a few questions:
- How does this product work? What feature about it saves water and how? An ad I recently saw in an irrigation trade magazine promoted a product as “water saving” but failed to disclose that the product would save water only in very specific situations found on very few irrigation systems.
- Will this product work with your irrigation system? Will it fit? A client of mine was recently told (by a city agency) he should switch his spray-type sprinklers to the new stream rotor nozzles to save water. These stream rotor nozzles have a minimum radius of 10 feet. His sprinkler system uses sprinklers with a radius of 8 feet and less. If he had made the requested change it would not have saved any water, it would have resulted in massive water waste!
- Does the firm proposing this service have extensive irrigation experience and knowledge? A lot of landscapers who have never installed a sprinkler are suddenly irrigation experts.
- Is this cost effective? Spending $100.00 to save $10.00 worth of water may be admirable but is it a wise move? (Yes, it may be in some situations.)
- Be wary of claims that you will save some large percentage of water. Most of the claims I have seen of 50-80% savings were based on the assumption that you have a really terrible quality irrigation system and that you leave it set to water for the maximum amount all year, even when snow is on the ground. In that case simply turning it off in winter could net you a 50% savings. So beware of blanket claims.
Free Irrigation Equipment!
Many water providers, particularly in drought areas in the USA, are offering discounts, coupons, and rebates on water-saving irrigation equipment. Some are even providing this equipment for free to local customers. Before you purchase any irrigation equipment, be sure to check with your local water provider to see if they are offering any freebies. You do like free stuff, don't you? I do!
Text and Images by Jess Stryker unless noted. Copyright © Jess Stryker, 1997-2011. All rights reserved.