April 20, 2010, New Bern, NC

Refining Residential:Using customer consumption records to

help manage water servicesUNC Environmental

Finance Center

2009 research for Urban Water Consortium

Contact: Mary Tiger, mwtiger@sog.unc.edu, 919-843-4958

Dedicated to enhancing the ability of governments and organizations to provide environmental programs and services in fair, effective and financially sustainable ways

Serving EPA Region 4

Refining residential

• Irrigators?

• Peakers?

• Significant contributors to the bottom line? 

• Responsive to drought restrictions and conditions?

Why residential?

Utilities included

• Fayetteville Public Works Commission (PWC)

• Greenville Utilities Commission (GUC)

• City of High Point (HP)

• Charlotte‐Mecklenburg Utilities (CMU)

• Orange Water and Sewer Authority (OWASA)

Our method

• Monthly consumption and billing data

• Records from July 2006‐December 2008

Input

• Extensive data cleaning

• Customer‐level analysis

Analysis • Household water use profiles

• Changes in household water use patterns

• Irrigation profile

Output

The climate of the timeline

Drought monitor status

Other major differences

• Demographics (MHI, home ownership, household size)

• Drought policies (triggers)

• Restrictions (voluntary, mandatory, prohibitions)

• Charges (marginal prices, surcharges)

Socioeconomic and housing characteristics

Median household income

% of owned occupied 

housing units

Average household size

Fayetteville City $44,086 57% 2.34

Greenville City $32,836 38% 2.08

High Point City $45,861 62% 2.42

Mecklenburg County

$57,033 64% 2.40

Orange County $54,390 59% 2.34

Data Source: U.S. Census Bureau, 2008 American Community Survey (ACS)

Key findings

• Profiling customers– Average water use

– Peaking behavior

• Drought response– Restrictions

– Mediashed effect

– Surcharges 

– Irrigation cutoffs 

Average water use

8%6%

4%

11%

5%

23%

17%

12%

26%

15%

20%

13%

9%

25%

14%

‐10%

0%

10%

20%

30%

PWC GUC HP CMU OWASA

Average Monthly Consumption of High Volume Households

Usage and billed amounts of householdsusing high volumes on average (avg. 11‐20k GPM) in FY08

% of Households % of Total Volume % of Total Billed Amounts

FY08

Drought response ‐ All

Utility Average household water usePercent change

FY07 FY08

CMU 6,436 6,109 ‐5%

PWC 4,980 5,410 +9%

OWASA 4,916 4,501 ‐8%

GUC 4,641 4,788 +3%

HP 4,467 4,199 ‐6%

Restrictions (usage) ‐ Fayetteville

Restrictions (revenue) ‐ Fayetteville

FY07 FY08

Total billed amount $29.6 million $33.0 million

Financial impact of changes in households’ average water use

“Mediashed” – High Point

Drought Surcharges ‐ OWASA

Irrigation shutoffs ‐ OWASA

0.30.3

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Million Gallons

Monthly usage by households with irrigation meters

Irrigation Meter usage (Outdoor Use) Standard meter usage (indoor use)

Metered and estimated irrigation

Utility Number of residential accounts (FY08)

Percentage with irrigation meters

Percent that irrigate with in‐ground systems(estimated)

Fayetteville 75,062 8% 12%

Greenville 29,397 3% 4%

High Point 36,864 3% 4%

CMU 225,247 2% 12%

OWASA 18,018 0.2% 5%

Questions?

Mary Tiger

Project Director, UNC Environmental Finance

(919) 843‐4958

mwtiger@sog.unc.edu