Even though California is not in a drought at present, our state is still encouraging the efficient use of water. In preparation for future droughts, many water agencies have been increasing water rates to cover the burden of infrastructure improvements, expanding storage capacity, and beginning conservation programs. As water rates continue to increase rapidly, one way to stabilize expenditures on water utility costs is to reduce outdoor water use in a long-term, sustainable manner.

We must also remember that whenever we use water, electricity is required to move that water; so, when we reduce outdoor water use, we are also reducing the electricity required to pump water from storage and treatment facilities onto our urban landscapes.

In addition to the energy required to move water, many of our landscapes in California are irrigated with potable water that is treated to drinking level standards, which requires a tremendous amount of energy only to have that water used for landscape irrigation. Close to 20% of the total energy used in California is required to move water in our state. The list of ways to conserve potable water in the landscape is extensive. At a very high level, most potable water saving efforts can be categorized into the following four groups:

  1. Alternative Water Sources
  2. Modifying the Landscape Water Requirement
  3. Efficient Operating Hardware
  4. Improved System Management

Alternative Water Sources consist of replacing or supplementing the current potable water used for landscape irrigation with an alternate water source, such as rain or storm water. If we can use recycled water for landscape irrigation, we are getting multiple uses out of our water. What makes water distinct from other natural resources is that it is a non-renewable resource, so if we can use it and reuse it multiple times, we ultimately conserve having to exhaust new supplies.

Unfortunately, one of the biggest obstacles to using alternative water sources is the high cost of putting the infrastructure in place or having enough space to install tanks or cisterns that can hold enough water to get us through our dry summer months in California. As infrastructure costs increase, so does the length of the payback period that can make the use of alternative water sources cost prohibitive for existing landscapes.
 

Modifying the Landscape Water Requirement can be done by removing, replacing or reducing high water use landscapes with lower water use plantings that are better suited for California’s dry and Mediterranean climate. The most common type of project in this category is a turf conversion project, where high-water-use turf is sheet mulched and replaced with low-water-use plantings and drip irrigation.

On October 13, 2023, California signed into law AB 1572, which places a ban on using potable water to water "non-functional turf" on public and CII (commercial, industrial and institutional) properties. Turf deemed "functional" and allowed to be irrigated using potable water is defined as any turf that is used as a recreational area or a community gathering space. AB 1572 excludes residential properties, multifamily properties, and cemeteries, but does include schools, HOAs, and common interest developments.

The ban on watering non-functional turf will be rolled out over a multi-year period starting with public properties (excluding disadvantaged communities) in 2027, commercial properties in 2028, homeowner association common areas in 2029, and finally public properties in disadvantaged communities in 2031, as funding allows.

Self-certification of compliance for all public, CII and properties over 5,000 square feet is set for June 30, 2030, and is currently set to be enforced by the State Water Resource Control Board and local agencies. Even though AB 1572 does not apply to residential properties, turf irrigated by sprinklers typically requires twice the amount of water required by moderate- water-using shrubs that are watered by drip irrigation.

Density reductions of high-water-use shrub plantings can also be included in this method of water reduction. If high-water-use plantings are removed, it is encouraged that that they be replaced with some type of planting to aid in carbon sequestration. Appropriately irrigated landscape plantings have the ability to take in carbon dioxide from the atmosphere and, through photosynthesis, sequester carbon into the soil. Some low-water-use, California native plants, such as Ceanothus, have the ability to pull nitrogen from the air and fix it in the soil to promote healthier soils. Even though it may be tempting to replace high-water-use plantings with synthetic turf, rock, or hardscapes, the negative impacts of the heat island effect and the decrease in carbon sequestration should be strongly considered.

Efficient Operating Hardware is the easiest way to save water in our landscapes. Several fundamental practices and methods to improve the efficiency of an irrigation system include the following:

  • Frequent Basic Repair and Adjustments– catch leaks and faulty components.
  • High Efficiency Nozzles– apply water more evenly and at a rate that reduces runoff.
  • Drip Conversions– replace inefficient spray heads with high efficiency low volume irrigation.
  • Pressure Regulation– reduce the high pressure in spray heads that causes misting.
  • Check Valves– retain water in piping and prevent it from leaking out of the lowest sprinkler.
  • Coverage Improvements– apply water more evenly, reducing dry or excessive wet areas.
  • Matching Precipitation Rates on Rotor Zones– ensure equal amounts of water are applied.
  • Proper Hydrozoning– group plants with similar water requirements on the same valve.

Improvements to system efficiency will not only save water, but will also typically improve plant health and the aesthetics of the landscape.

 Improved System Management focuses on applying the correct amount of water to the landscape to match daily weather changes. Most "smart" or "weather-based" irrigation controllers have online connectivity through either cellular or WIFI communication. This cloud connectivity improves the ease of programming and monitoring of controllers to automatically adjust watering schedules according to plant water needs. Out of all of the water saving products on the market, smart controllers typically have the shortest payback period because they are the one item you can install that will have the greatest impact over the entire system.

In addition to being able to monitor and make frequent scheduling adjustments, cloud connected smart controllers save more water when paired up with a flow sensor and a master valve so that the smart controller can monitor and automatically react to abnormal flow conditions. Problems such as a catastrophic break or a stuck valve that would run all night can now be shut down instantly. When paired up with flow sensing, a cloud connected smart controller can also notify the manager immediately via text or email.

At a bare minimum, if a smart controller is not in the current budget, the use of a simple device such as a rain sensor can save thousands of gallons of water from being wasted during an unexpected rain event.

As smart as our systems can be, they should still be inspected frequently. The US EPA promoted its Fix A Leak Week campaign in the spring as a reminder that systems should be inspected and repaired at the onset of the irrigation season. In addition to "Fix a Leak Week," the US EPA encourages that systems be inspected frequently throughout the irrigation season. Unfortunately, even the best cloud-based smart controller equipped with flow sensing cannot diagnose a sprinkler that is out of adjustment or misdirected and may be spraying into the street.

When deciding which water saving technique to implement, the cost of the project should be considered. The amount of water to be saved often depends on how well the water was previously managed. The amount of money to be saved also depends on local water rates. It may be difficult to produce savings on a site that has historically been under-watered. Water budgets for all landscapes can be developed using historical weather data and site square footage. For more information and support on water saving techniques or budgets, the Irrigation Association and the US EPA’s WaterSense program are great resources.

Eric Santos is extremely passionate about water use efficiency and volunteers his time to promote water conservation. He has served as a board director for the Irrigation Association, California Landscape Contractors Association, and is currently a board director for ReScape California. Santos currently works for Epic Irrigation Services and Water Management based in Livermore and teaches landscape irrigation and landscape sustainability at Las Positas College in his spare time.