Water Consumption Research Project Phase 2 Methodology circa 4 - - PowerPoint PPT Presentation

Water Consumption Research Project

Phase 2

Methodology

• circa 4 months meter readings from 7,439

households

– Four counties: Dublin, Kildare, Meath and Wexford – Covers period December 2013 to May 2014 – Different architecture types

• Consumption per day calculated as total

metered quantity divided by number of days from date of install to date of meter read.

Methodology

• Focus of WCRP Phase 2 is to gather data to study

consumption in households with children

• Door to door survey carried out by market

research company

• Sensitive sites removed from list
• Data collected:

– Architecture type – Number of bedrooms – Number of occupants per house, including adults and children

• Assumption that surveys are answered and

recorded honestly and in good faith

• No data on socio-economic profile or age of

respondents

• Sample selection limited to households that had

meters installed between December 2013 and January 2014

• Survey limited to 4 counties in Leinster
• Bias towards suburban areas and associated

demographics and architecture types

• No apartments in this phase of the WCRP

Limitations

Assumptions

• Households greater than 800 litres/day removed from

analysis on the basis of proposed first fix policy1

• Household usage is most closely correlated with
• ccupancy
• Children are defined as children under 18 living in the

household.

• Sample is not representative of CSO population census

but provides a useful snapshot of households metered so far

• Annual consumption is extrapolated from available data
• Proposed household allowance is 30m3 per year

1A total of 63 outliers were removed. This includes one household removed as it had no adult

• ccupants.

Survey sample (ex outliers)

Children 1 2 3 4 5 6 7 Total Adults 1

58 20 17 9 2 1

107 2

179 169 285 144 35 10 4 1

827 3

72 40 28 13 2 1

156 4

31 12 2

45 5

3 2 1 1

7 6

1 1

2 Total 343 244 334 167 39 12 4 1 1,144

Results (litres per person per day)

Children 1 2 3 4 5 6 7 Adults 1

176 148 96 103 94 126

• 2

141 102 91 78 81 82 68 40

3

104 86 81 82 73 79

• 4

102 80 109

• 5

101 78 77 54

• 6
• 70

92

Comparison to Phase 1

Phase 1 Phase 2

Sample size litres/person Sample size litres/person 1 occupant 94 171 58 176 2 occupants 335 140 199 142 3 occupants 353 108 258 102 4 occupants 428 94 365 92 5 occupants 265 83 189 79 6 + occupants 111 84 75 81 Total 1,586 1,144 Apartment 33 162

• Detached

435 110 178 101 Semi-detached 748 106 498 103 Terraced 370 109 468 106 Total 1,586 1,144

Survey sample (ex outliers)

Children 1 2 3 4 5 6 7 Total Adults 1

58 20 17 9 2 1

107 2

179 169 285 144 35 10 4 1

827 3

72 40 28 13 2 1

156 4

31 12 2

45 5

3 2 1 1

7 6

1 1

2 Total 343 244 334 167 39 12 4 1 1,144

Two adult households

20 40 60 80 100 120 140 160

1 adult 2 adults 2 adults, 1 child 2 adults, 2 children 2 adults, 3 children

m3 per household per year

Incremental consumption

Scatterplot – Phase 1

y = 20.181x + 56.493

50 100 150 200 250 300 350 400 1 2 3 4 5 6

m3 per household per year Occupants

Scatterplot – Phase 2

y = 18.453x + 58.725

50 100 150 200 250 300 350 400 1 2 3 4 5 6 7 8 9 10

m3 per household per year Occupants

Billable quantity – 38m3 per child

20 40 60 80 100 120 140 160 180 1 2 3 4 5 6 7 8 Billable quantity (m3 per year) Occupants

No Children Children

Billable quantity – 20m3 per child

20 40 60 80 100 120 140 160 180 1 2 3 4 5 6 7 8 Billable quantity (m3 per year) Occupants

No Children Children

Average bill index* @ 38m3 per child

Children 1 2 3 4 5 6 7 Adults 1

100 140 60 69 8 161

• 2

207 136 100 55 61 60 36

3

239 176 154 151 73 32

• 4

338 230 374

• 5

439 293 260 35

• 6
• 316

465

• *2 adults, 2 children = 100

Average bill index* @ 20m3 per child

Children 1 2 3 4 5 6 7 Adults 1

55 97 67 103 95 227

• 2

113 99 100 86 107 124 75

3

130 120 128 145 119 157

• 4

184 150 259

• 5

239 187 197 102

• 6
• 200

309

• *2 adults, 2 children = 100

Billing distribution

50 100 150 200 250 300 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Indicative m3 per year Percentile Billable quantity @ 38m3 Billable quantity @ 20m3

@ 20m3 increases the billable quantity by 41%

Effective volumetric rates

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Percentage of volumetirc tariff Households percentile

Effective Rate @ 38m3 Effective Rate @ 20m3

+ 15 %

@ 20m3 increase in households paying a bill from 75 to 90%

Results @ 38m3 per child

• Households with children pay less than

households without children

• In total, 25% of households do not receive a

bill

– 34% of households with children do not receive a bill versus 4% of households that do not have children

• 61% of water consumed is non-billable
• Effective volumetric rate, on average, is 34%
• f the actual volumetric rate

Results @ 20m3 per child

• Households with children pay less than

households without children

• In total, 10% of households do not receive a

bill

– 12% of households with children do not receive a bill versus 4% of households that do not have children

• 45% of water consumed is non-billable
• Effective volumetric rate, on average, is 47%
• f the actual volumetric rate