1. Using Grey/Rain Water in a Residence Richard Caputo

2. Generic Residential Grey Water System Grey Water 120 – 150 gal/day for 2 BR Residence of 4 ~ 50,000 gal/yr ~ 6,600 ft3 ~ 66 units of water Equivalent to 33” Rain on Roof of 2400 ft2 House* ~ Water Needed for 2000 ft2 Garden (~ 25 gal/ft2/yr) In General, If Grey Water is Half House Water, then if Outside Water Use Then Water Reduction with (fraction of total)Grey Water Use Is 1/31/3 (max share) 1/21/4 2/31/6 3/41/8 1” Rain on Typical 2400 ft2 House = 1500 gal (~ 0.6 gal/ft2)

3. Case Study of Using Grey & Rain Water Two BR 2 person, 1630 ft2 House & 1/7 acre (~ 6000 ft2) Intensive Garden ( see www.extraordinaryhouse.net) System 1 – Potable water – Entire garden uses drip System 2 – Redesign Zones for similar water needs with – Half spray on natives (minimize salt) and half drip – Potable water System 3 – Same as 2 – Potable water spray – Grey/rain water drip

4. Grey/Rain Water System Overview 2006 SANDEE Award House in Julian System Used – Multi-component with pumps, valves, filter with backwash, potable H2O connection, etc based on ReWater System (~ $3300 equipment) – Other Possibilities: Simple --- gravity flow with French drains on contours Complex --- multi tanks/pumps/etc 5 Grey Water Irrigation Zones plus 2 Potable Water Spray Zones Underground Release with 12 gal/hr emitters on ¾” Lines Sand Filter with Periodic Back Flush Rain Water Roof (1500 ft2) Collection With Gravity Feed to Sump Tank/Pump to 3000 gal Stainless Steel Tank (~ $1500 – $3000) Controller with Midnight Check to Finish Irrigation Cycle – Rain Water Used First – Potable Water Used as Last Resort

5. Grey Water System Schematic

6. Grey Water System Components Sand Filter, 3-way Valve, Solenoid Vales, Check Valve, Irrigation Valves, Back-flow Device (RPZ)

7. Grey Water System Components Previous Components Plus Controller to Control Fresh Water Zones and Grey Water Zones which can distribute water in 2 minute increments every day

8. Grey Water System Components Previous Plus 100 gal Sump Tank with 1.5 HP Pump/Float

9. Rain Water Storage Tank 3000 Stainless Steel Tank – holds ~ 3” rain Gravity Feed from Roof Down Comers to Sump Tank/Pump Used to Back-up Grey Water System at Mid-night Check

10. Water Usage System 1: Potable Irrigation Using 1gal/hr Drips Everywhere – Annual Average 537 gal/day (194 house & 341 garden) – ~ 21 gal/ft2/yr for garden System 2: Redesign --- Each Zone with Similar Water Use Plants – Only potable water used – Half Garden on Potable Overhead Spray (keep salt off natives) – Half Garden on Potable Underground 12 gal/hr emitters – 496 gal/day Total Usage (194 house & 302 garden) – 11% less – ~ 18 gal/ft2/yr for garden System 3: Same as 2 with mixture of potable, grey and rain water – 368 gal/day Total Usage (194 house/174 garden)–49% less than #1 – ~ 10.6 gal/ft2/yr for garden

11. Water Usage, gal/day System - 2 Person plus - ~ 1/7 acre (6000 ft2) Garden Total Usage House Usage Garden Usage Gal/day (%total) % Reduction Garden Total 1. Drips Throughout Garden 535 194 341 (64%) Base 2. Redesign With Only Potable Water 496 194 302 (61%) 11% 7% 3. Redesign with 1/2 Potable & 1/2 Grey/ Rain Water 368 194 174 (47%) 49% 31%

12. RESULTS Save 11% Garden Water by Redesigning Zones Compared to 100% Drip System by: Zones with Similar Water Needs Potable Spray on Natives Grey/Rain Water Saves Additional 42% Combined Savings Total of 49% of Garden Water Potable/Grey/Rain Water System and Zone Redesign Cut Garden Water in Half from 21 to 10.6 gal/ft2/yr Bottom Line: – Save of 31% of Total Water Use

13. Cost Comparison APPLICATIONCOST, $/af FARMING  $ 15 WHOLESALE (MWDSC)$370 – $480 RESIDENTAL, 2005$900 - In 2010 at +4%/yr$1300 - In 2015 at + 4%/yr$1600 - In 2020 at +4%/yr$2400 GREY WATER, Residence ($3300 system + $400 labor + $200 for emitters in irrigation system) - Grey Water + Zone Redesign$1125 - Grey Water only, cash$1500 - loan at 6% & 30 yr life$2100 - loan at 6% & 20 yr life$2560 Julian Well Water District,2010$4000

14. Conclusions Grey Water Is: – Very Cost Effective in Julian – Approx. Cost of City Water Can Reduce Water Use up to 1/3rd Need to Overcome Current Hostility from San Diego County