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Presented by:Willem Wegelin

WRP Consulting Engineers

Modified IWA water balance

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NO DROP CERTIFICATION

BLUE DROP NO DROP GREEN DROP

1 WSP 1Strategy, planning &

implementation1 W2RAP

2 Asset management 2 Asset management 2 Asset management

3 Technical skills 3 Technical skills 3 Technical skills

4Credibility and

accountability4

Credibility and

accountability4

Credibility and

accountability

5 Compliance 5Compliance &

Performance5 Compliance

6 Local regulation 6 Local regulation

7 Customer care

Incentive-based regulation

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Objectives of No Drop certification

To change behaviour towards improved

water use and water demand management by

municipalities

To reduce water loss and increase water use

efficiency

To use credible data to report against defined

targets

To benchmark within defined municipal- and

performance clusters and/or contribute to

sector-wide benchmarking initiatives

STATE OF NRW / WATER LOSSES IN SA

(2009/10 data)

(2011/12 data) (2011/12 data) (2011/12 data) (2011/12 data)

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STATE OF NRW / WATER LOSSES IN SA

(2015/16 data) (2015/16 data)(Dec 2016 data)

(2011/12 data)

(2012/13 data) (2012/13 data) (2012/13 data) (2011/12 data)

8 Large Systems 8 Large Systems Non-delegated

(2015/16 data)

National

(2014/15 data)

8 Large Systems

WATER LOSS BENCHMARKING

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Basic principles

• The IWA water balance should provide a true reflection of the water use efficiency, water loss and non-revenue water in a distribution system

• The water balance should be based on actual data with minimum estimation

• All information must have an audit trail

• The water balance is based on the potable water supply (system input volume) and does not allow for treatment losses

• The water balance is a volumetric balance and does not include non-payment

Modified IWA water balance

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Authorised connection?

• Connection

- Yes – unmetered and

informal

- Usually installed out of

desperation or convenience

• Authorised

- No – installed by user

- Yes – utility allows user to

continue using the

connection

Number of connections

• A connection is defined as any formal or

accepted point of water supply

• Authorised = no intension of disconnecting

• All other connections should be considered

unlawful and removed

• This means all users supplied with potable water

must have a metered or unmetered connection

• Use number of accounts from billing system

- No of meters distorted by combination meters

- No households ≠ no of connections

- No stands = no of connections (outdated cadastral)

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Connection decision flow chart

Connection

Authorised Unauthorised

Illegal connection

Remove or formalise

Metered Unmetered

Billed Unbilled

Authorised consumption Water losses

Mains leakage

• Connection yes / no

• Authorised yes / no

• Metered yes / no

• Billed yes / no

Water Losses

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Connection leakage (before meter)

• Connection yes / no

• Authorised yes / no

• Metered yes / no

• Billed yes / no

Water Losses

House connection

• Connection yes / no

• Authorised yes / no

• Metered yes / no

• Billed yes / no

Authorised Metered Billed

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Internal Plumbing Leakage

• Connection yes / no

• Authorised yes / no

• Metered yes / no

• Billed yes / no

Authorised Metered Unbilled

Yard connection

• Connection yes / no

• Authorised yes / no

• Metered yes / no

• Billed yes / no

Authorised Unmetered Unbilled

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Tanker supply

• Connection yes / no

• Authorised yes / no

• Metered yes / no

• Billed yes / no

Authorised Metered Unbilled

Inefficient water use and wastage

• Connection yes / no

• Authorised yes / no

• Metered yes / no

• Billed yes / no

Authorised Metered Unbilled

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Live stock watering

• Connection yes / no

• Authorised yes / no

• Metered yes / no

• Billed yes / no

Unauthorised Connection - Remove

Public stand pipe

• Connection yes / no

• Authorised yes / no

• Metered yes / no

• Billed yes / no

Authorised Metered Unbilled

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Informal connection

• Connection yes / no

• Authorised yes / no

• Metered yes / no

• Billed yes / no

Authorised Unmetered Unbilled

Water loss or Authorised consumption

Authorised consumption

Meter or unmetered

Billed or unbilled

After connection

Water losses

Commercial losses

Physical losses

Before connection

Reticulation (Government) Stand (Consumer)

Connection

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Modified IWA water balance

After the connection

Before the connection

EXAMPLES

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Indigent water user (metered)

Actual use =

18 kl/month

Free Basic Water =

6kl/month

Balance =

12 kl/month

Metered

unbilled

Metered billed

(billed at zero rate)

Flat rate water user (unmetered)

Estimated actual use =

22 kl/month

Flat rate consumption =

10 kl/month

Balance =

12 kl/month

Unmetered

unbilled

Unmetered billed

Billed for 10kl/month

(Includes FBW)

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KEY PERFORMANCE INDICATORS

Key Performance Indicators

• Litres / capita / day

• Losses m3 / connection / day

• Losses m3 / km mains / day

• % Non-revenue water

• Infrastructure Leakage Index- Current Annual Real Losses___

Unavoidable Annual Real Losses

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Litres / capita / day

WTW

4 Ml/d

Formal water supply areas

10 000 water users

Informal water supply areas

6 000 water users

3 Ml/d

1 Ml/d

300l/c/d

60 l/c/d

250 l/c/dFormal water supply areas

10 000 water users400 l/c/d

UARL = ( 18 x Lm + 0.8 x Nc + 25 x Lp ) x P

Unavoidable Annual Real Losses

Length of mains

Average

operating

pressureNumber of service

connectionsLength of underground

pipe:- not used in

South African cases

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Infrastructure leakage index (ILI)

• The ILI provides an indication of the actual physical leakage versus

the expected minimum level of leakage

• For example, an ILI of 4 indicates that the physical leakage in the

distribution network is 4 times higher than expected.

ILI =

CARL

UARL UNAVOIDABLE ANNUAL REAL LOSSES

UARL = (18 x Lm + 0.8 x Nc + 25 x Lp) x P

CURRENT ANNUAL REAL LOSSES

CARL = system input volume – components of

authorised consumption - apparent losses

Metro No Drop basic information

0

10

20

30

40

50

60

70

BUF CPT EKU ETH JHB MAN NMB TSH

55 54

44

53

65

57 60

55

Ave

rage

sys

tem

pre

ssu

re (

m)

0

2 000

4 000

6 000

8 000

10 000

12 000

14 000

BUF CPT EKU ETH JHB MAN NMB TSH

2 954

10 86710 096

12 219 11 847

3 6584 454

10 116

Len

gth

of

mai

ns

(km

)

0.0

0.5

1.0

1.5

2.0

2.5

3.0

BUF CPT EKU ETH JHB MAN NMB TSH

1.01.1

2.1

1.6

2.7

1.6

1.0

1.3

Ho

use

ho

lds

per

co

nn

ecti

on

0

100 000

200 000

300 000

400 000

500 000

600 000

700 000

BUF CPT EKU ETH JHB MAN NMB TSH

104 639

631 491

478 979

488 270

476 614

133 972219 157

530 674

121 694

21 000

54 973

156 855105 572

8 338

163

46 400

Metered connections: Unmetered connections:

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Metro No Drop Results

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

CPT EKU ETH TSH NMB JHB MAN BUF

83.5%

76.0% 75.0%70.5% 67.6% 67.3%

56.7% 54.9%

No

Dro

p S

core

Average performanceGood

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

BUF CPT EKU ETH JHB MAN NMB TSH

39.5%

21.1%

37.8%39.4%

40.9%

31.4%

42.3%

23.6%

0

50

100

150

200

250

300

350

BUF CPT EKU ETH JHB MAN NMB TSH

242

200

285

252

333

305

249275

0

1

2

3

4

5

6

7

8

BUF CPT EKU ETH JHB MAN NMB TSH

4.2

2.6

6.36.8

7.5

5.2

6.2

4.4

Average ILI = 5.4Average l/c/d = 274

Average No Drop score = 69% Average NRW = 34.3%

Other Physical Water Loss Indicators

0

10

20

30

40

50

60

70

80

BUF CPT EKU ETH JHB MAN NMB TSH

77

60

53 5349

39

49

57

Co

nn

ecti

on

s /

km m

ain

s

0

5

10

15

20

25

30

BUF CPT EKU ETH JHB MAN NMB TSH

18

9

17

22

28

15

21

16

Rea

l lo

sse

s (m

3/

km m

ain

s /d

ay)

0

100

200

300

400

500

600

BUF CPT EKU ETH JHB MAN NMB TSH

241

153

316

411

570

375

434

272

Rea

l lo

sse

s (m

3/c

on

nec

tio

n/d

ay)

0

1

2

3

4

5

6

7

8

BUF CPT EKU ETH JHB MAN NMB TSH

4.2

2.6

6.36.8

7.5

5.2

6.2

4.4

Infr

astr

uct

ure

Lea

kage

Ind

ex

22

5

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0

750 000

1 500 000

2 250 000

3 000 000

3 750 000

4 500 000

0.0

0.5

1.0

1.5

2.0

2.5

3.0

40 45 50 55 60 65 70 75 80 85 90 95 100

Connection losses (

m3/a

nnum

)

Infr

astr

uctu

re L

eakage I

ndex (

ILI)

Connections / km

Density of connections vs ILI

Constants

• Length of mains = 1000 km

• Average pressure = 50 m

• CARL = 6 000 000 m3/annum

• Connection losses = 110 litres / connection / day

𝐼𝐿𝐼 =𝐶𝑢𝑟𝑟𝑒𝑛𝑡 𝐴𝑛𝑛𝑢𝑎𝑙 𝑅𝑒𝑎𝑙 𝐿𝑜𝑠𝑠𝑒𝑠

( 18 x Lm + 0.8 x Nc) x P

40 000 connections 100 000 connections

CONCLUSIONS

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Misleading IWA Water Balance

System input

Authorised consumption

Water loss

Real loss

Billed metered

Billed unmetered

Apparent loss

Revenue water

Non-revenue

water

50% 50%

50% 50% 50%

20%

30%

Informative IWA Water Balance

Apparent loss

System input

Authorised consumption

Water loss

Unbilled metered

Unbilled unmetered

Real loss

Billed metered

Billed unmeteredRevenue water

Non-revenue

water

27%

50%

73%

23%

50%

17%

10%

50%

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Conclusions

• Include all authorised connections supplied

by the utility in the water balance

• Authorised connection = connection with no

intension of disconnecting

• Losses before the user connections =

physical or commercial losses

• Consumption and “losses” after the user

connection = authorised consumption

• Review all KPIs to ensure key issues are

identified and addressed

THANK YOU