Appendix L4. ESTIMATED TOTAL WATER USE (ETWU)

The project's Estimated Total Water Use (ETWU) is calculated using the following formula:

ETWU = ETo × 0.62 × ETAF × Area

Legend:
ETWU	=	Estimated water use based on plant material (gallons per year)
ETo	=	Reference Evapotranspiration (inches per year)
0.62	=	Conversion factor (to gallons per square foot)
ETAF	=	Plant Factor (PF) divided by Irrigation Efficiency (IE)
Area	=	Landscaped Area (square feet)

 

Average ETAF
Total ETAF × Area	(B)
Total Area	(A)
AVERAGE ETAF	(B) ÷ (A)

 

Average ETAF for Regular Landscape Areas must be 0.55 or below for residential and 0.45 or below for non-residential

All Landscape Areas
Total ETAF × Area	(B + D)
Total Area	(A + C)
AVERAGE ETAF	(B + D) ÷ (A + C)

 

(Ord. No. 4492, § 9, 6-21-2016)