October 2012
4-31
4.7
Dipper Wells
Savings Potential
Water savings can be achieved in two ways: by retrofitting the dipper well to reduce
the flow rate or by replacing a dipper well with a metered faucet or an ENERGY STAR
qualified commercial undercounter dishwasher.
Dipper Well Retrofit With In-Line Flow Restrictor
Retrofitting a dipper well with an in-low flow restrictor can be a simple way to save
water.
Current Water Use
To estimate the water use of an existing dipper well, identify the following informa-
tion and use Equation 4-12:
••
Flow rate of the existing dipper well. Most dipper wells have flow rates between
0.5
and 1.0 gpm.
46
••
Average daily use time.
••
Days of facility operation per year.
Equation 4-12. Water Use of Dipper Well (gallons per year)
= Dipper Well Flow Rate x Daily Use Time x Days of Facility Operation
Where:
••
Dipper Well Flow Rate (gallons per minute)
••
Daily Use Time (minutes per day)
••
Days of Facility Operation (days per year)
Water Use After Retrofit
To estimate the water use after retrofitting an existing dipper well with an in-line
flow restrictor, use Equation 4-12, substituting the flow rate of the retrofit in-line flow
restrictor for the flow rate of the existing dipper well. An efficient, retrofit in-line flow
restrictor should provide a maximum flow rate of 0.3 gpm.
Water Savings
To calculate the water savings that can be achieved from retrofitting an existing dip-
per well, identify the following information and use Equation 4-13:
••
Current water use as calculated using Equation 4-12.
••
Water use after retrofit as calculated using Equation 4-12.
46
EBMUD,
op. cit.
