ç REDUCING POTABLE WATER USED FOR IRRIGATING NEW LANDSCAPING IN CALIFORNIA Dave Jaeckel|Michelle Camp|Sarah Sugar Yale School of Forestry and Environmental Studies Source: The New York Times

Presentation Roadmap Overview of “Waste or Unreasonable Use” California Residential Development Trends Alternatives to Turf and Potable Water Potential Water Savings Costs of Saving Water Summary Questions? 2 Sources: United States Drought Monitor, NBCnews.com Roadmap

3 Overview of “Waste or Unreasonable Use” Waste or Unreasonable Use Sources: California Constitution, SWRCB “It is hereby declared that because of the conditions prevailing in this State the general welfare requires that the water resources of the State be put to beneficial use to the fullest extent of which they are capable, and that the waste or unreasonable use or unreasonable method of use of water be prevented, and that the conservation of such waters is to be exercised with a view to the reasonable and beneficial use thereof in the interest of the people and for the public welfare.” (Cal. Const. art. X, §2) “Reasonable use” is not a static concept, and depends on the circumstances of the case (e.g., periods of long drought) SWRCB has the authority to order the termination of misuse

4 Overview of “Waste or Unreasonable Use” Seven-Factor Test Sources: SWRCB, Water Rights Decision 1600 (1984) SWRCB uses a seven-factor test to evaluate whether a use is unreasonable: 1. Other possible beneficial uses for the water 2. Whether the excess water serves other beneficial uses 3. The probable benefits of water savings 4. The amount of water reasonably required for beneficial use 5. The amount and reasonableness of the cost of saving water 6. Whether the methods of saving water are conventional 7. The availability of a physical solution

5 Projected Development ( ) Sources: United States Census Bureau Building Permits 1. Los Angeles: 252, Riverside: 169, San Diego: 124, San Bernardino: 116, Santa Clara: 96,411 * Includes single family, two family, three and four family, and five or more family permits. Higher ET, larger yard sizes, more potable water demand California Residential Development Trends

6 Solutions Solutions to Reduce Potable Water Use Sources: California Model Landscape Ordinance, Pacific Institute Water smart landscaping practices o 75% less water requirements than cool season turf (uses drip and microspray irrigation) o Cost effective Alternative water sources (non-potable water) o Rainwater harvesting o Graywater systems Focus on new residential development for traction

ç Avg. Daily Graywater Generated: 84 gallons (3 people per household) ç ç ç Estimated Potable Water Need for Irrigation (Turf) 71,687 – 86,216 gallons / year Avg. Roof Size: 1,500 square feet (1.26 inches average monthly precipitation LA County) Irrigated Yard: 3,370 square feet (cool season turf grasses with sprinklers) ç Ex: New Los Angeles Single Family Home

ç Graywater Potential: + 30,660 gallons per year ç ç ç Estimated Potable Water Need for Irrigation (Low Water) 17,921 – 21,554 gallons / year 53,766 – 64,662 gallons / year savings Rainwater Harvesting Potential: + 11,310 gallons per year Irrigated Yard: 3,370 square feet (low water plantings with drip or microspray irrigation) ç Ex: New Los Angeles Single Family Home

9 Water Savings // Water Smart Landscaping Sources: Factor 4: Potential Water Savings How much potable water could be saved if new development in California installed low water landscapes?

10 Water Savings // Water Smart Landscaping Sources: Pacific Institute, DWR, PPIC, US Census Bureau Factor 4: Potential Water Savings 12,922-13,715 AF/Y Savings 12,922-15,889 AF/Y Savings 12,922-14,799 AF/Y savings switching from turf to low water plants

11 Water Savings // Water Smart Landscaping Factor 4: Potential Water Savings 320, ,404 AF Savings 320, ,093 AF Savings 320, ,749 AF savings switching from turf to low water plants Sources: Pacific Institute, DWR, PPIC, US Census Bureau

12 Water Savings // Water Smart Landscaping Factor 4: Potential Water Savings 320, ,404 AF/Y Savings 106, ,135 AF/Y Savings 106, ,135 AF savings every 5 years Sources: Pacific Institute, DWR, PPIC, US Census Bureau 213, ,270 AF/Y Savings

13 Factor 4: Potential Water Savings Water Savings // Alt. Water Systems With low water landscapes implemented, how much water (non potable) could be provided by graywater and rainwater harvesting systems?

14 Water Savings // Rainwater Harvesting Factor 4: Potential Water Savings 2,200 gallon cistern 2.64 inches for 1,900 gallons Sources: Pacific Institute, DWR, PPIC, US Census Bureau, LADWP

15 Water Savings // Graywater Systems Factor 4: Potential Water Savings Average Annual Graywater Potential (6,500 AF/Y) Sources: Pacific Institute, DWR, PPIC, US Census Bureau, LADWP

16 Water Smart Landscaping // Costs Sources: Factor 5: Cost of Saving Water How much do low water landscapes cost in relation to turf, and are graywater, rainwater, microspray and drip systems economical?

17 Water Smart Landscaping // Costs Factor 5: Cost of Saving Water Installing a water- efficient landscape comes with no upfront cost premium and results in substantial cost-savings over the long-term. Sources: landscape contractor survey evidence, Home Depot Mulch Calculator, SNWA Xeriscape Conversion Study

18 Microspray and Drip Irrigation // Costs Sources: emeraldlawnsprinklers.com, naturallandscapeandirrigation.com, hunterindustries.com Factor 5: Cost of Saving Water Sprinkler system Drip system Microspray system Each system costs approx. $2-4/sq ft of installation.* * According to landscape contractor survey evidence

19 Alternative Water Supplies // Rainwater Harvesting // Costs Factor 5: Cost of Saving Water ~$400 $2,600/AF* ~$1,300 $20,000+/AF* 110-GAL TANK 2200-GAL TANK Sources: Hey!Tanks LA, Pacific Institute High upfront cost + short wet season = low to no ROI* (however, rebates can increase cost-effectiveness) * According to landscape contractor survey evidence

20 Alternative Water Supplies // Graywater Systems // Costs Source: Greywater Action, 2014 Factor 5: Cost of Saving Water

21 Summary Waste or unreasonable use is a viable approach to addressing potable water used to irrigate residential landscaping in California. 12,922-14,799 AF/Y of potable water could be saved annually in California with new development using low water landscaping practices. 320, ,749 AF of potable water could be saved from if new development uses low water landscaping practices. Graywater and rainwater systems can help address the remaining water need for low water plants, especially graywater systems. Installing low water landscapes comes with no upfront cost premiums and results in substantial savings over time.

22 Questions? Source: NBCnews.com