Asset Management Economic Analysis for Small Meter Replacement Eric Brainich Asset Manager Portland Water Bureau May 2008

Small meter in Portland Portland Water Bureau small meters Replacement cost = $13 million Annual income measured by small meters: $23 million for water $56 million for sewer Size Count 5/8” 149,000 3/4” 14,000 1” 13,000

5/8” meters Estimate meter degradation curve Calculate unrecorded water revenue loss as meter accuracy declines during life of meter Cost of replacing meter Minimize life-cycle cost of meters Methodology

Factors to consider in estimating degradation: Make/model of meter Model A & Model B Consumption (vs. age) of meter 500 / 1000 / 1500 / 2000 / 2500 / 3000 ccf Test flow rates Low = 0.25/0.5/1.0 gpm Medium = 3 gpm High = 10 gpm Weighted flow rates Low = 15% Medium = 75% High = 10% Estimating meter degradation

Random sample of 441 5/8” meters (222 of Model A and 219 of Model B) Minimum 30 samples for each model and consumption category Plotted on GIS to provide qualitative check to ensure randomness of sample data

Portland Water Bureau Meter Shop

Meter Test Results

Economic Analysis – Least Cost Life Cycle

Economic sensitivity analysis

Removal from service based on accuracy and meter type. Recommends using sample test data to identify groups of meters with accuracy problems to ensure money used to exchange meters is spent on the poorest performing meters. 1/ Taken from M6 Manual AWWA meter guidelines 1

Least-cost life-cycle analysis used to justify replacement timing (ensures cost of program not more than “revenue loss” or rate increase needed to cover unrecorded water usage) Random sample of meters Weighted flow rates depend upon local consumption patterns Conclusions & Recommendations