This program enables agencies to purchase delivery vouchers for mulch application as a permanent outdoor water efficiency measure. The program supports state-mandated water use efficiency requirements and regional conservation goals.
Vouchers may be issued with a defined value, quantity, (Example - $40 for up to 10 cubic yards) and a 30-day expiration period to encourage timely participation. Unused vouchers may be reassigned or refunded to ensure full utilization of public funds.
Mulching is a recognized outdoor water efficiency Best Management Practice (BMP) in California. In Bay Area climates, mulch reduces soil evaporation, moderates soil temperature, and improves soil moisture retention, resulting in lower applied irrigation water.
| Landscape Application | Typical Mulch Depth | Estimated Water Savings |
|---|---|---|
| Residential planting beds | 2–3 inches | 20–30% irrigation reduction |
| Trees and shrubs | 3 inches | 30–40% irrigation reduction |
| Newly planted landscapes | 2–3 inches | Reduced watering frequency (1–2 days per week) |
Water savings are directly correlated to the amount of irrigated landscape area treated with mulch. The following estimates reflect conservative planning ranges commonly accepted by Bay Area water agencies.
| Irrigated Landscape Area | Typical Residential Context | Estimated Annual Water Savings |
|---|---|---|
| 500–1,000 sq ft | Small urban lots, townhomes | 2,500–5,000 gallons |
| 1,000–2,500 sq ft | Typical single-family homes | 5,000–10,000 gallons |
| 2,500–5,000 sq ft | Large residential lots | 10,000–20,000 gallons |
| 5,000+ sq ft | Estate or multi-zone landscapes | Site-specific evaluation recommended |
Under SB 606 and AB 1668, urban retail water suppliers must comply with long-term water use efficiency standards that include an outdoor residential irrigation component. Programs that permanently reduce applied irrigation water support compliance with these standards.
Mulch application contributes to compliance by:
For planning and reporting purposes, agencies may conservatively estimate savings using:
Program participation data (number of households, irrigated area treated, and mulch volume delivered) may be incorporated into annual SB 606 / AB 1668 reporting, Urban Water Management Plans, and Water Shortage Contingency Plans.
| Participation Level | Estimated Annual Water Savings |
|---|---|
| 100 households (typical SF Bay Area) | 500,000 – 1,000,000 gallons |
| 500 households | 2.5 – 5 million gallons |
| 1,000 households | 5 – 10 million gallons |
Supports SFPUC Water Conservation Program objectives, reduces discretionary outdoor demand, and advances long-term water use efficiency targets under SB 606 / AB 1668.
Aligns with EBMUD’s Water Conservation Master Plan by promoting permanent landscape efficiency and reducing peak-season irrigation demand.
Provides BAWSCA member agencies with a scalable, regionally consistent outdoor conservation program that produces measurable, reportable savings.
Water savings estimates are derived from guidance published by the California Department of Water Resources (DWR), University of California Cooperative Extension, U.S. Environmental Protection Agency WaterSense Program, and regional Bay Area water agency conservation studies.
Savings values reflect conservative planning assumptions commonly accepted for Urban Water Management Plans, SB 606 / AB 1668 compliance documentation, and municipal conservation reporting. Actual savings may vary based on site conditions, irrigation system efficiency, soil type, plant selection, and climate zone.