Whether you water your outdoor plants manually or have a irrigation system, there's always room for water conservation. Here are some tips to save water in your yard.
Here's how you can use water wisely and keep your plants healthy.
- Adjust your watering schedule. Pay attention to rain showers, cooler weather, and periods of extended high temperatures. Adjust your watering times accordingly.
- Keep in mind that established trees and shrubs typically don't need much supplemental water. Except for maybe a deep soak or two in the hottest days of summer, established trees and shrubs don't need a great deal of additional water. They have root systems that tap into deeper sources of water. Newly planted trees, however, need regular watering for the first couple of years.
- Water in the morning or evening. Heat and wind cause water to evaporate more quickly. Watering early in the morning or later in the evening (when the sun is low in the sky) helps keep evaporation to a minimum.
- Watch for puddles and runoff. Avoid applying water faster than it can soak into the soil.
- Aerate or dethatch your lawn. If water isn't penetrating the soil, your lawn may need to be aerated or dethatched.
- Water lawns with one inch of water per week (more during long, hot dry spells). Water lawns separately from other plants. The best practice for watering your landscape is to apply 50 percent of what you put on grass to perennials and shrubs, and 75 percent to vegetables (but new plant starts require more water).
- Sign up for the Weekly Watering Number. The Regional Water Providers Consortium takes the guesswork out of watering by emailing you the amount of water (in inches) your lawn will need each week. The weekly watering number is available every Thursday from April to September. It considers local weather according to your zip code.
Adding compost to soil on a regular basis is one of the easiest ways to have a productive and healthy landscape while conserving water. Mixing compost into the top six inches of your soil improves the soil's ability to hold water and increases nutrients and beneficial soil organisms. Soils rich with organic matter act like a sponge for water, preventing runoff and storing more water in the root zone, where plants can use it.
Evaporation is the main source of water loss from soil and, therefore, from your plants. Adding a layer of mulch around your plants can significantly reduce the amount of soil-water evaporation caused by the sun and wind. Mulches can also help reduce erosion and help with weed control.
Mulches come in a variety of shapes, sizes, and colors. Mulch can be organic (bark, wood chips, or compost) or inorganic (gravel or landscape cloth). Both provide a protective layer covering the soil surface. Apply organic mulches annually or as needed throughout the year. To be most effective, apply one to two inches of compost, leaves, or sawdust, or two to four inches of coarsely shredded bark or wood chips.
How you choose to irrigate depends on your budget, the type of plants you have, and the size of your landscape. Regardless of what you use to irrigate—a hose, drip, or automatic irrigation system—there are several best practices that are important to follow:
- Prepare the soil to ensure proper drainage and water-holding capacity. Healthy soil needs less water than poor soil.
- Water late in the evening or early in the morning, when the water is less likely to evaporate.
- Actively manage and maintain your irrigation system. Check regularly for leaks and misdirected spray.
- Water lawns with one inch of water per week (more during long, hot dry spells). Water lawns separately from other plants. A good rule of thumb for watering your landscape is to apply 50 percent of what you put on grass to perennials and shrubs, and 75 percent to vegetables (but new starts require more water).
Portland uses almost twice as much water in the summer as it does in the winter. Reduce your use and apply for rebates when you purchase new water-saving multistream rotator sprinkler nozzles and WaterSense-labeled irrigation controllers. Any active City of Portland drinking water account is eligible. With proper installation, programming, and maintenance, homeowners and businesses can use these upgrades to save thousands of gallons of water each year.
If you water your landscape with handheld hoses, consider using these devices to help you water efficiently:
- Soaker hose: Soaker hoses release water to plants through thousands of tiny pores that drip water slowly and evenly at low pressure. They are a cheap alternative to drip irrigation systems for watering shrubs and bushes.
- Sprinklers: If you use a portable sprinkler, try to use one that waters low to the ground to prevent misting and evaporation into the air. Also look for sprinklers with rotor action that lay water down at a slower rate than those with a constant spray pattern. Applying water at a slower rate allows water to be absorbed into the soil instead of running off.
- Timers: A hose timer that lets you set the start time and duration of a watering session is a good way to control your manual sprinkler. Battery-operated, electric, or wind-up timers are all available. They are typically attached to the hose bib and can be reset for each use.
- Hose nozzle: Automatic shutoff nozzles are an easy way to keep a hose from running. They are often available with multiple spray patterns such as mist, shower, and jet. The Portland Water Bureau offers FREE hose nozzles for customers.
Drip irrigation is one of the most efficient ways to water plants, shrubs, vegetable gardens, and outdoor container plants. With drip irrigation, water works its way slowly into the soil and goes directly to the roots of the plant, keeping evaporation to a minimum. Drip irrigation is ideal for clay soils, where adding too much water too quickly can result in puddles and runoff.
Most garden centers carry drip irrigation kits or components, and the manufacturers of these products publish instructions that go with them. With regular maintenance, a drip system can be very efficient and help you save water.
Choosing the right pieces for your drip system
Drippers or emitters, bubblers, and microsprayers are the types of heads used on a drip irrigation system. These heads allow you to customize your system to deliver the right amount of water where it's needed.
- Drippers or emitters generally water at rates of ½, 1, and 2 gallons per hour, while bubblers water at slightly higher rates. The slowest drip rate is best for clay soils; high drip rates are best suited to sandy soils.
- Microsprayers use the most water in a drip system (up to 15 gallons per hour) but still use much less than standard above-ground sprinklers. They are best for ground covers, flower beds, and pots where drippers and soakers won't fit or where plants need more humidity.
Hooking up your drip system
A drip watering system needs clean water and low water pressure to work properly. You should install a filter (to prevent drip devices from clogging over time) and a pressure regulator. To avoid overwatering your plants, install a timer on the hose bib.
In-ground automatic irrigation
An automatic irrigation system consists of a collection of pipes, tubing, valves, and pop-up spray heads or rotors. The City of Portland requires a plumbing permit and backflow device for any new automatic irrigation system. The backflow device prevents irrigation water from flowing back into the municipal water system.
An automatic irrigation system can include the following:
- Spray heads: Pop-up spray heads can be adjusted to spray in a quarter, half, or full circle. Spray heads can put out a lot of water in a short time. This means these systems have multiple, short run times to ensure that the water penetrates the soil.
- Rotors: These heads deliver water more slowly than spray heads, allowing soil to take in the water without puddling too quickly. Used in the past for large turf areas such as sports fields, rotors are now available and practical for smaller turf areas. If you purchase multistream rotator nozzles, you may be eligible for a rebate.
Components are typically connected to an automatic irrigation controller. A properly programmed irrigation controller turns your system on and off, acting like a thermostat for your sprinklers, applying water only when plants need it. If you purchase a WaterSense-labeled irrigation controller, you may be eligible for a rebate.
There are different types of controllers available:
- Clock-timed: These types of controllers rely on manual schedule entry. Some are capable of programming multiple run times, which is essential if you are using spray heads. They can also come with a water budget feature so that you can easily adjust run times for warmer or cooler days.
- Weather-based: Many types of weather-based controllers are on the market today. Some use third-party communication with weather stations; some are pre-programmed with historical weather data; some have on-site weather stations. Solar radiation and temperature are the primary drivers of water use in plants. Wind is also a factor. Weather-based controllers use some or all of these variables to water various landscape materials.
- Soil moisture sensors: You can add sensors to existing controllers or install a complete system with sensors and a related controller. Sensors measure the moisture content in the soil and tell the controller to water or not, depending on the level of moisture in the soil.
- WaterSense-labeled irrigation controllers: To earn the Environmental Protection Agency's WaterSense label, landscape irrigation smart controllers must be able to meet the watering needs of a landscape without overwatering. As with all other WaterSense-labeled products, WaterSense-labeled controllers are third-party certified to ensure that they meet the WaterSense criteria for efficiency and performance.
Getting the most from your irrigation system
- Install a rain sensor. Rain sensors or rain shutoff devices prevent an automatic system from turning on during or after rainfall. If you have a soil moisture sensor, you don't need a rain sensor.
- Adjust the direction of your sprinkler heads. Make sure your sprinkler heads are sending water to the plants, not the pavement.
- Repair broken heads and pipes immediately. Broken heads and leaky pipes can waste a lot of water and money. Regularly inspect your system for broken pieces. An automatic system still needs maintenance.
Choosing a water-wise landscape contractor
In‐ground automatic sprinkler systems require regular maintenance to function well. Hiring a knowledgeable contractor can ensure that your system continues to perform for years to come.
The US Environmental Protection Agency (EPA) WaterSense Program certifies irrigation professionals who practice water‐efficient irrigation techniques. An irrigation professional certified by a WaterSense-labeled program can design, install, maintain, or audit your irrigation system to make sure it uses the right amount of water to maintain a healthy landscape while minimizing waste. Find more information from the EPA on how to find a WaterSense-certified professional.
Below is a list of landscape and irrigation contractors who are licensed in the State of Oregon, certified by the Irrigation Association (IA), and partner with the EPA's WaterSense Program. Disclaimer: The Portland Water Bureau lists these contractors to provide customers with information about WaterSense. The Water Bureau does not recommend or endorse any listed contractor. This list is updated every six months. If you are certified by a WaterSense-labeled program, are available for hire within the Portland metropolitan area, and are missing from this list, please contact the Portland Water Bureau Efficiency Program. List last updated January 6, 2020.