UNIT FACTOR RATE ASSIGNMENT STUDY, PHASE I-II

MWEA Annual Conference June 20, 2016

BACKGROUND

Oakland County Schedule of Unit Assignment Factors Table

Utilized by the Oakland County Water Resources Commission (WRC) and many communities for determination of water & sewer use factors for different development types

Uses a Single Family Residential property as the baseline for all comparisons by assigning a unit factor of 1.0 to this use

Describes many different development types & assigns a Residential Unit Equivalent (REU) factor relative to a Single Family Residential use

PURPOSE

The current Schedule has not been updated since 1998

Disputes have been filed with the County over sewer connection fees & rates

Residential water usage is declining

High-efficiency appliances & fixtures are becoming increasingly popular

55 Non-Residential Categories Total

PURPOSE

Phase I :

Updating & Quantifying the current Residential Equivalent Unit (REU)

- Analyze residential billing data for actual metered water usage

- Analyze SEMCOG demographic and industry water/wastewater usage guidelines

Phase II:

Updating the 1998 Schedule of Unit Assignment Factors Table

PHASE I BACKGROUND

Current Assumed Usage of a Single Family Residential Sewer Customer:

90 Gallons/Person x 3.5 People = 315 Gallons/1 Day 1 Day 1 Single Family Household 1 Single Family Household

315 Gallons x 365 Days = 114,975 Gallons = 15,370 ft3 1 Day 1 Year 1 Year 1 Year ACTUAL Demographics for Oakland County: People per Household (2010) – 2.49 People per Household (2013) – 2.44

INDUSTRY WATER GUIDELINES

Source: Phase I Standardized Water Usage

(gallons/person/day)

Oakland County (WRC) 113

GLUMRB 125

Haestad Methods 93

Innovyze 94

USGS (Michigan Average) 80

USGS (U.S. Average) 98

Aquacraft, Inc. 69

GLUMRB = Great Lakes Upper Mississippi River Board

Haestad Methods = Corporation specializing in Water Distribution Modeling / Wastewater Collection Modeling & Design

Innovyze = Corporation specializing in Water/Wastewater Utilities Modeling and Planning

Aquacraft = Corporation specializing in Water Use Studies & Water Conservation Programs

PHASE I METHODOLOGY

11 WRC Billing Communities Were Surveyed:

Bingham Farms

Bloomfield Hills

Commerce Township

Farmington Hills

Highland Township

Keego Harbor

Lyon Township

Oakland Township

Orchard Lake

Oxford Township

Royal Oak Township

PHASE I METHODOLOGY

Actual WRC community quarterly meter billing data was collected and analyzed from 2010-2013

Only meter readings from November – April (non-irrigation usage) were obtained

Usage data from 5/8-inch & 1-inch residential water meters were analyzed

Groupings of 5 and 10 unit (1 unit = 100 CF) usage intervals for residential 5/8” and 1” meters were developed and plotted against the number of account readings within each interval over the 4 year study period

The data was analyzed at 90% / 95% / 100% of community billing accounts where 90% excluded the high and low 10% of accounts and 100% excluded 0% of accounts to illustrate impact on water usage by high and low end accounts in the analysis

Water usage was analyzed, comparing 80% / 90% / 95% of water usage being returned to the system as wastewater

Sewer lead infiltration rates were also analyzed at (5% / 10% / 15%) of water used

Actual billed usage averages for each community were calculated along with a weighted overall usage for all 11 communities

DEMOGRAPHIC ANALYSIS

Data analyzed:

Population

Occupied Units

People per Household

Median Housing Value

Median Household Income

Average Water Usage (Units)

As these values increase, so does water usage

COMMUNITY Consumption/ Household (gpd)

Avg. Household Value

BINGHAM FARMS 187.2 $391,900

BLOOMFIELD HILLS 203.6 $715,300

COMMERCE TOWNSHIP 153.7 $229,300

FARMINGTON HILLS 166.0 $238,300

HIGHLAND TOWNSHIP 201.1 $212,900

KEEGO HARBOR 134.6 $156,900

LYON TOWNSHIP 180.4 $242,400

OAKLAND TOWNSHIP 241.4 $342,000

ORCHARD LAKE 189.3 $588,200

OXFORD TOWNSHIP 171.4 $342,000

ROYAL OAK TOWNSHIP

143.0 $99,800

OAKLAND COUNTY 179.3

WATER USE VS. PEOPLE PER HOUSEHOLD

WATER USE VS. WATER RATES

EXAMPLE COMMUNITY WATER USAGE CALCULATION

COMMERCE TOWNSHIP

COMMERCE TOWNSHIP SEMCOG POPULATION DATA

Demographics 2010 2013 Change (2010-

2013)

Population 35,874 36,570 1.9%

Occupied Units 13,220 13,674 3.4%

People per Household 2.71 2.67 -1.5%

Median Housing Value $229,300 N/A N/A

Median Household Income $82,691 N/A N/A

COMMERCE TOWNSHIP DISTRIBUTION OF WATER CONSUMPTION

1” & 5/8” Meter Data Averaged from 2010-2013 Winter Quarters

COMMERCE TOWNSHIP WATER USAGE WITH 10% OF HIGH AND LOW END ACCOUNTS EXCLUDED

Middle of 90% of 1” & 5/8” Meter Data Averaged from 2010-2013 Winter Quarters

COMMERCE TOWNSHIP WATER USAGE WITH 5% OF HIGH AND LOW END ACCOUNTS EXCLUDED

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Commerce Township: Distribution of Water Consumption

COMMERCE TOWNSHIP ANALYSIS SUMMARY

Calculated water use for 1 REU in Commerce Township is 153.7 gal/day with 10% of high and low end account usage analyzed

People/ Household

Residential Accounts

4-Year Avg. Winter Use (Units/Qtr)

Avg. from Statistically

Reduced Data

Gal/day/ Household

Gal/person/ day

2.67 4,912 19.26 18.49 153.7 57.6

COMMUNITY WATER USAGE STANDARDIZED TO WASTEWATER FLOW NOT INCLUDING I/I

Community

People per Household

(SEMCOG 2013)

Water Use Derived from Analysis

(Gal/Person/Day)

Water Use Derived from Analysis

(Gal/Household/Day)

80% Wastewater Use Derived from Analysis (Gal/Household/Day)

BINGHAM FARMS 2.05 91.3 187.2 149.8

BLOOMFIELD HILLS 2.43 83.8 203.6 162.9

COMMERCE TOWNSHIP 2.67 57.6 153.7 123.0

FARMINGTON HILLS 2.34 70.9 166.0 190.9

HIGHLAND TOWNSHIP 2.65 75.9 201.1 160.9

KEEGO HARBOR 2.31 58.2 134.6 107.7

LYON TOWNSHIP 2.76 65.4 180.4 144.3

OAKLAND TOWNSHIP 2.87 84.1 241.4 193.1

ORCHARD LAKE 2.73 69.4 189.3 151.4

OXFORD TOWNSHIP 2.79 61.4 171.4 137.1

ROYAL OAK TOWNSHIP 2.44 58.6 143.0 114.4

Weighted Average 2.49 69.2 172.2 137.8

COMMUNITY/INDUSTRY WASTEWATER USAGE GUIDELINE COMPARISON INCLUDING I/I

Community

People per Household (SEMCOG

2013)

Water Use Derived from Analysis

(Gal/Person/Day)

Wastewater Use Derived from

Analysis Including I/I

(Gal/Household/Day)

WRC (using 3.5 people per household)

(Gal/Household/ Day)

GLUMRB (Gal/House-

hold/Day)

Haestad Methods

(Gal/House-hold/Day)

Innovyze (Gal/House-

hold/Day)

USGS (Michigan Average)

(Gal/House-hold/Day)

USGS (U.S. Average)

(Gal/House-hold/Day)

Aquacraft, Inc.

(Gal/House-hold/Day)

BINGHAM FARMS 2.05 91.3 172.2 315.0 205.0 151.7 153.8 150.88 184.8 130.7

BLOOMFIELD HILLS 2.43 83.8 187.3 315.0 243.0 179.8 182.3 178.848 219.1 154.9

COMMERCE TOWNSHIP

2.67 57.6 141.4 315.0 267.0 197.6 200.3 196.512 240.7 170.2

FARMINGTON HILLS 2.34 70.9 152.7 315.0 234.0 173.2 175.5 172.224 211.0 149.2

HIGHLAND TOWNSHIP

2.65 75.9 185.0 315.0 265.0 196.1 198.8 195.04 238.9 169.0

KEEGO HARBOR 2.31 58.2 123.8 315.0 231.0 170.9 173.3 170.016 208.3 147.3

LYON TOWNSHIP 2.76 65.4 166.0 315.0 276.0 204.2 207.0 203.136 248.8 176.0

OAKLAND TOWNSHIP

2.87 84.1 222.1 315.0 287.0 212.4 215.3 211.232 258.8 183.0

ORCHARD LAKE 2.73 69.4 174.2 315.0 273.0 202.0 204.8 200.928 246.1 174.1

OXFORD TOWNSHIP 2.79 61.4 157.7 315.0 279.0 206.5 209.3 205.344 251.5 177.9

ROYAL OAK TOWNSHIP

2.44 58.6 131.6 315.0 244.0 180.6 183.0 179.584 220.0 155.6

Weighted Average 2.49 69.2 158.4 315.0 249.0 184.3 186.8 183.3 224.5 158.8

PHASE I DATA ANALYSIS

A Steering Committee was formed to:

Review the Phase I Report

Provide input on the updated Schedule of Unit Assignment Factors

Updated Single Family Residential Usage = 8,238.67 cf/yr

Over 50% less than the existing REU usage

Updated REU Value = 2,106 cf/quarter

Based on utilization of 95% of the usage being returned to the wastewater system & 5% infiltration and inflow contribution

1998 SCHEDULE REVIEW

The entire Schedule was reviewed based on current demographics & development trends

The Schedule was re-formatted to create ‘main categories’ (Auto; Food, Beverage & Retail; Personal care; etc.)

Some classifications were eliminated, while others were added for a total of 53 non-residential properties surveyed

PHASE II DATA ANALYSIS

The data collection goal for the Study was to collect up to 5 representative properties within each non-residential subcategory (for a total of 265 businesses)

Data collection included specific water usage data for the same Phase I study period of 2010-2013 during the winter months

Usage and business category data for Phase II included the original 11 WRC billing communities as well as the City of Novi & Bloomfield, West Bloomfield & Waterford Townships

Additional service use data was collected from SEMCOG, field visits & phone calls to the various business types to calculate non-residential REU unit factors

PHASE II DATA ANALYSIS

Service use data included:

Square Footage

Meter Size

Number of Fixtures

Number of Employees

Number of Seats (restaurants /

banquet halls)

Number of Students (schools)

Number of Beds (hospitals)

Number of Dentists (dental offices)

Number of Doctors (medical offices)

Number of Rooms/Seats (medical / dental offices)

Number of Gas Pumps (convenience stores)

Number of Stalls/Bays (auto service repair / car washes)

Several Factors Hampered Reaching the Desired Business Survey Goal:

Nail & Tanning Salons / Spas being housed in strip malls with no individual meter

Business Owners / Managers unwilling to provide information

Majority of the participating communities did not contain several business classes included in the survey

PHASE II DATA ANALYSIS

CONCLUSIONS & RECOMMENDATIONS

Regression Charts were developed for each business class:

Showing positive or negative correlation with water usage (R2 value)

Charts showing negative correlations will require further analysis by the Committee & WRC

Recommended Unit Assignment Factors were developed based on the R2 values for each service unit

A Summary Table was developed that compared:

The 1998 Schedule REU values with our recommended REU values

REU values per service unit

CONCLUSIONS & RECOMMENDATIONS

The Steering Committee provided input on the data & initial recommendations

REU values based on ‘number of employees’ was not preferred

In instances where no strong positive correlations could be made, a unit assignment factor was based on ‘per facility’.

BANQUET HALLS REGRESSION CHART

1998 Unit Factor 0.500 per 1,000 sq. ft. Updated Unit Factor 0.38 per 1,000 sq. ft. (R2 value = 0.8198) Recommended Unit Factor 0.18 per fixture (R2 value = 0.7232)

R² = 0.4161

R² = 0.8198

R² = 0.7232

R² = 0.5225

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SQ. Ft./Employees/Fixtures

1,000 Square Feet

Employees

Fixtures

Seats

Linear (1,000 SquareFeet)

Linear (Employees)

Linear (Fixtures)

Linear (Seats)

Banquet Halls

BOWLING ALLEYS REGRESSION CHART

1998 Unit Factor 0.160 per alley Updated Unit Factor 0.32 per alley (R2 value = 0.5950) Recommended Unit Factor 0.36 per 1,000 sq. ft. (R2 value = 0.8198)

R² = 0.8198

R² = 0.609 R² = 0.595

R² = 0.6049

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Linear (Fixtures)

Bowling Alleys

DAY CARE / EARLY LEARNING REGRESSION CHART

1998 Unit Factor NA Updated Unit Factor NA Recommended Unit Factor 0.06 per child/student (R2 value = 0.898)

R² = 0.0367

R² = 0.0151

R² = 0.0312

R² = 0.0898

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Linear (Students)

Daycare / Early Learning

QUICK SERVICE RESTAURANTS W/O DINING & PUBLIC RESTROOMS REGRESSION CHART

1998 Unit Factor 1.80 per restaurant Updated Unit Factor 1.00 per restaurant Recommended Unit Factor * 1.00 per restaurant (no strong positive correlations exist)

R² = 0.7873 R² = 0.7109

R² = 0.0031

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Linear (Fixtures)

Linear (Employees)

Restaurants w/o Dining & Public Restrooms

Purpose

Allows the user to input a custom value which is then applied against a linear trend to produce an REU value

Allows the user to choose the ‘best fit’ for water usage per business class

REU CALCULATOR APPLICATION

REU CALCULATOR APPLICATION

WRC will review the Phase I Report & Recommendations for approval

Possible collection of more usage data

Updated Schedule anticipated by Early Fall 2016

NEXT STEPS

THANK YOU!

Laura Gruzwalski Johnson & Anderson

4494 Elizabeth Lake Rd Waterford, MI 48328

248-681-7800 lgruzwalski@ja-engr.com