Water Audit, Water Audit Basics, terms in Water Audit, Water Balance diagram, Water Audit Methodology,Types of Water Losses, Apparent loss and real losses, Ways to manage apparent loss and real losses, apparent loss performance indicator, Infrastructure leak index

1. By
SRIDHAR S I
M.Tech Environmental Engineering
2014604305
Agricultural Engineering College and Research Institute
Tamil Nadu Agricultural University
Water Audit: A Tool for
Assessment of Non-Revenue
Water

2. • Water Audit is a qualitative and quantitative analysis of water
consumption to identify means of Reducing, Reusing and
Recycling of water.
Water Audit?

3. • To utilize water resources capably and efficiently.
• To keep check on unwanted excess use of water.
• Helpful in planning and developing a water storage structures
like dam, lake, bunds etc,
• To identify thefts, meter inaccuracies and unauthorized water
use.
• To identify losses both physical and non-physical.

4. • Audits are also used to estimate the cost associated with
these losses to the water system by balancing the amount of
water produced with the amounts billed.
• an effective tool for realistic understanding and assessment of
the present performance level and efficiency of the service
and the adaptability of the system for future expansion &
rectification of faults during modernization.

5. • Volume from own sources: The volume of water withdrawn from
water resources (rivers, lakes, streams, wells, etc) controlled by the
water utility.
• Water Imported: Water purchased from a neighbouring water
utility.
• System Input Volume: The total volume input to the water supply
system.
• Water Exported: Water conveyed and sold by the water utility to
neighbouring water systems.

6. • Water Supplied: Total volume of water supplied to the utility
system.
• Authorized Consumption: Volume of metered /unmetered
delivered to the authorized customer.
• Water Losses: The difference between System Input Volume
and Authorized Consumption.
• Revenue Water.
• Non-revenue Water.

7. Water Balance
System Input volume =
Water incoming Water outgoing
Water Audit Basics

8. Water Balance Diagram
Source: IWA / AWWA (2000)

10. 1 • Source Evaluation
2 • Calculation of authorized consumption
3 • Evaluation of apparent losses
4 • Evaluation of real losses
5 • Performance Measurement
Water Audit Methodology
Source: IWA / AWWA (2000)

11. Determining System Input.
Identification of water sources ( wells, Surface
water intakes...)
At any cause outputs must equal inputs.
Volume of the input is determined by
metering the source – Master Meter.
Proper Maintenance of master meter is
necessary.
Source Evaluation1

12. • Good billing records.
• Calculating revenue water
• Sub-metering
• Billed metered consumption + billed
unmetered consumption = Revenue water.
• Authorized consumption = revenue water +
unbilled authorized consumption
Calculation of authorized Consumption2
Billed meter
consumption
Billed unmetered
consumption

13. • Loss = System input – Authorized Consumption.
Evaluation of Water Losses3

14. Types of Losses
• Apparent Losses
• Real Losses

15. Apparent Losses

16. • Water being consumed but not being paid.
• Also called as paper loss.
• Apparent loss occurs at the rate charged to the
utilities customer.
• Real loss occurs at the cost of producing the water
Evaluation of Apparent Losses3.1
Unit cost of
apparent loss
Unit cost of
real loss

17. • Unauthorized use identification.(theft)
• Flow Measurement along the distribution lines.
(sub-metering)
• Correcting the meter inaccuracies. (replacement).
• Isolation of lines using values.

18. Apparent Loss Performance Indicator
• ALI = apparent loss index
• CAAL = current annual apparent loss
• UAAL = unavoidable annual apparent loss
• UAAL = 5% of water sales.
• If ALI = 1 (better performance).
Source: IWA / AWWA (2000)

19. Real Losses

20. • Real loss accounts for a greater volume
compared to apparent loss.
• Leakage on mains.
• Good to keep a record of leak locations,
repairs, and estimated losses.
Evaluation of Real Losses3.2

22. Leakage on transmission or distribution mains:
• They are visible, reported and easily repaired.
• Calculate number of leaks
• Annual leakage volume = number of reported
burst x avg. Leak flow rate x leak flow
duration.

23. • Leakage and Overflows at Utility's Storage
Tanks Leakage.
• Leakage on Service Connections up to
Point of Customer Metering.
– deducting mains leakage and storage tank
leakage from the total volume of real losses,
– Includes hidden and background leakages.

24. 1
•Component analysis2
•Top down method
3 •Night flow analysis

25. • Standardized top-down water balance.
• apparent losses are to be calculated first and
then by subtracting it from total loss, the real
loss is obtained.
• accuracy of real loss depends on correct
estimation of apparent losses.

26. • Each unit of water supplied and component are
analysed.
• Required data are,
1
•Total length of pipe network and no. of service connections
2
•Average service connection length between meter connection and
customer meter.
3
•Total no. Of distribution repairs per year
4
•Number of service connection repairs
5
•Average system pressure across the entire system
6
•Volume of storage tank leaks and overflows

27. Minimum night
flow time
(02.00 -04.00 hrs)
Assessment of
legitimate night
consumption
Real loss = MNF –
amt. Of night
consumption
1 2
3
Source: Lambert et al (2001)

28. • Compiling the final figures:
Reliable Results
( Real Losses)
Night flow
analysis
Top down
approach
Component
Analysis

29. Real Loss Performance Indicator
• Use of Infrastructure Leak Index.
• CARL – Current Annual Real Losses.
• UARL – Unavoidable Annual Real Losses.
Source: IWA / AWWA (2000)

30. Unavoidable Annual Real Losses.
• It is impossible to eliminate all real losses from
a distribution system
- some losses are “unavoidable”
- some leakages are believed to be undetectable (too
small to detect) or uneconomical to repair

31. • UARL (L/day) = (18 x Lm + 0.80 x Nc + 25 x Lp) x P
where,
• Lm = Length of mains in km
• Nc = Number of service connections
• Lp = Total length in km of underground connection
pipes (between the edge of the street and customer
meters)
• P = Average operating pressure in m

32. Infrastructure Leak Index.
• A better indicator
• Describes the quality of infrastructure
management.
• Is the ratio of Current Annual Real Losses to
Unavoidable Annual Real Losses

34. Source: Lambert et al (2002)
CARL

35. • Water loss percentage.
• ALI
• ILI
Performance Measurement4

36. Study Area: Amaravthi City, Maharastra.
Author: Dighade R.R and M.S Kadhu (2015)

37. Amaravathi City Water Supply System
• System Designed for 156 MLD.
• For a population of 6 lakhs water is supplied at
the rate of 135 LPCD.
• Water is supplied in zone wise manner for 3-4
hrs per day.

38. Water Audit in Sainagar Zone
DMA – District metered area

39. Annual Water Balance Diagram
Unit: ML/year

40. Water audit of DMA-3 in Sainagar
zone

41. Results and Discussion
• System Input volume – 292 ML/ year.
• The NRW by volume - 115.05 ML / year.
• amounts to 39.40 %, of system input
volume.
• In financial terms it amounts to 12 lakhs per
year.
• Indicates a lot of water potential and cost for
saving.

42. • Water Audit helps to quantify all forms of losses
and helps in reducing the non-revenue water.
• Assess the performance of the utility system.
• Ultimately the availability of water in not the
actual problem. But efficient management of
water is the major issue that we need to work on.
• And for this efficient management we have the
best tool :-
“WATER AUDITING”.

43. • American Water Works Association (2009). ―Water audits and loss control
programs. AWWA manual, M36, American Water Works Association, Denver,
USA.
• Darwish Shpair J (2010). Water Losses Analysis and Its Indicators. Al-Aqsa
University Journal (Natural Sciences Series) , Vol.14(1), 1-28.
• Dighade R.R and M. S. Kadu (2015). Development of water balance table for
reducing non revenue water in water distribution network. International e-journal
on emerging trends in science, technology and management, Vol. 1(1)
• Ganorkar R.A, P.I.Rode, S.A Deshmukh, R.M Dhoble. Water Audit- A Tool for
Assessment Of Water Losses. International Journal Of Computational Engineering
Research , Vol. 3
• Lambert A.O and R.D. McKenzie. Practical Experience in using the Infrastructure
Leakage Index.