Addressing Non-Revenue Waterefcnetwork.org/documents/2013/11/waterloss_session-3.pdf · Addressing...

Addressing Non-Revenue Water

Smart Management for Small Water Systems

www.efcnetwork.org

www.efcnetwork.org


Water

Imported

Own

Sources

Total

System

Input

( allow

for

known

errors )

Total

System

Input

(allow

for

known

errors)

Water

Supplied

Water

Exported

Water

Supplied

Water

Exported

Water

Losses

Authorized

Consumption

Water

Imported

Own

Sources

Total

System

Input

( allow

for

known

errors )

Water

Imported

Own

Sources

Total

System

Input

( allow

for

known

errors )

Total

System

Input

(allow

for

known

errors)

Water

Supplied

Water

Exported

Water

Supplied

Water

Exported

Water

Losses

Authorized

Consumption

Water

Losses

Authorized

Consumption

Real

Losses

Apparent

Losses

Unbilled

Authorized

Consumption

Billed

Authorized

Consumption

Non-

Revenue

Water

Revenue

Water

Leakage & Overflows at Storage

Billed Unmetered Consumption

Billed Metered Consumption

Billed Water Exported

Leakage on Service Lines

Leakage on Mains

Customer Metering Inaccuracies

Unauthorized Consumption

Unbilled Unmetered Consumption

Unbilled Metered Consumption

Systematic Data Handling Error

www.efcnetwork.org


Water that is used by customers known to the water system but is not billed

Water loss due to theft, slow meters and billing issues, also called commercial losses

Water loss due to leakage in the system

www.efcnetwork.org

How much non-revenue

water is acceptable?

• Identify a goal or appropriate level of non-revenue water

Facility and supply limits and economics will help you

decide the level of action you should take

• In some states this is required

√ California: < 10% unaccounted-for water

√ Colorado: proposed reporting requirements for NRW water

√ Ohio Public Utility Commission – will not allow private

utilities to charge customers for production of NRW in

excess of 15%

√ Some states now adopting the AWWA approach (GA, FL,

TN)

www.efcnetwork.orgwww.efcnetwork.org

Water Losses

Authorized ConsumptionTotal

Systeminput

Real Losses

Apparent Losses

Billed Authorized Consumption

Unbilled Authorized Consumption

Addressing Unbilled

Authorized Consumption

www.efcnetwork.org

Addressing Unbilled


• Water you don’t bill for

Fire fighting

Flushing

Public parks and golf courses

Street cleaning

Municipal facilities

Other uses??


www.efcnetwork.org

Can your utility control Unbilled Authorized

consumption more effectively?

Addressing Unbilled


Meter, estimate, report


www.efcnetwork.org

• Meter Municipal Services Fountains

Municipal Buildings

Parks

• Conservation


Addressing Unbilled Authorized Consumption


www.efcnetwork.org

• Flushing Filling mains – compute volume

Fire flow tests – measure time and flow

Flushing – measure time and flow

Keep records

Meter




www.efcnetwork.org

• Fire fighting

Record number of events

Estimate flows

Meter?




www.efcnetwork.org


Improving Unbilled Unmetered Data Quality

• Estimate unbilled metered events

• Record number of unbilled events and develop a standard formula to calculate volume

• Conduct testing to look at actual vs. estimated flow

• Install metersUnbilled Authorized Consumption

Start Here

Work Towards

Here

www.efcnetwork.org


• Read meters on a regular basis

• Start meter testing program

• Develop systematic testing program

• Install automatic meter reading

• Test all meters annually

• Repair or replace all underperforming meters


Improving Unbilled Metered Data Quality

Continue Working

Work Towards

Here


Addressing Apparent Losses

Water Losses

Authorized ConsumptionTotal

Systeminput

Real Losses

Apparent Losses



www.efcnetwork.org

• Unauthorized consumption

• Customer meter inaccuracies

• Systematic data handling errors

Apparent Losses


www.efcnetwork.org

• Process is largely administrative

• No physical defect that allows water

to be loss

Apparent Losses


www.efcnetwork.org


• Illegal taps

• Theft at hydrant

• Open bypasses

• Illegal use of fire

services

Apparent Losses


Image from Maynilad Water Services – Manila, Phillipineshttp://www.puretechltd.com/case_studies/water_pipeline/maynilad_water.shtml

www.efcnetwork.org


• Estimate number of major incidents

• Evaluate types of incidents and number of

occurrences of each

• Identify losses due to unauthorized

consumption and aim to reduce

• Examine policy and procedures for gaps

that allow for fraudApparent Losses


Start Here

Work Towards

Here

www.efcnetwork.org


• Implement a monitoring and

enforcement plan

• New regulations to target specific

types of unauthorized consumption

• Review annually

Apparent Losses


Continue Working

Work Towards

Here

www.efcnetwork.org

Customer meter inaccuracies

• Customer meter accuracy declines with age

and varies between meter type and meter

manufacturer

• Meter types

Nutating Disc

Oscillating Piston

Turbine

Apparent Losses


www.smartmeasurement.com

www.efcnetwork.org

How accurate are your

customer meters?

• Accuracy depends on style and

manufacturer

Data Courtesy Utah State University and Water Research Foundation

Apparent Losses

www.efcnetwork.org

Customer meter inaccuracies

• Target suspected problem areas due to

meter age or type and test small

number of meters

• Standardize meter testing over a larger

area

• Replacement program for older meters

• Increase meter testing or replacement

program over a wider area

Apparent Losses


Start Here

Work Towards

Here

www.efcnetwork.org

Systematic Data Handling Errors

• Errors that occur between when a meter is

read and when a bill is sent to the

customer

• Can be due to:

Billing system entry errors

Account adjustments

Invalid meter consumption readings

Meter rollover

Meter change out

Apparent Losses


www.efcnetwork.org

Systematic Data Handling Errors

• Conduct internal review of meter reading

& billing systems

• Conduct internal checks on data vailidity

and meter reading procedures

• Conduct annual internal checks of billing

data

• Conduct third part audit with specific

review for possible data handling and

meter reading errorsApparent Losses


Start Here

Work Towards

Here


Addressing Real Losses

Water Losses


TotalSysteminput

Real Losses

Apparent Losses



www.efcnetwork.org

Real Losses

Addressing Real LossesLeakage

• Leakage on mains

• Leakage on service connections

• Leakage at finished water storage tanks

including overflow events

www.efcnetwork.org

Real Losses


Which leaks cause more water loss?

Small hidden leaks Large surface leaks

Leakage

www.efcnetwork.org

Small hidden leaks can lead to most water loss

• Constant flow of low-level leaks causes more water

loss than spectacular water main breaks

5-gpm leak running

100 days =

720,000 gallons

500-gpm leak running

4 hours = 120,000 gallons

Real Losses


www.efcnetwork.org

Real Losses


Is the point you can see water the location of the leak?

Yes or No?

Leakage

www.efcnetwork.org

Pinpointing a leak

• Water will take the path of least resistance

Leaks don’t always surface (especially the small constant or slowly increasing leaks)

May surface far away from the leak

Leaks may occur in places difficult to access (e.g., under a stream, highway or wetland)

• Pinpointing a leak saves money in repair costs

Real Losses


www.efcnetwork.org

1. Respond faster to known leaks

2. Asset Management

3. Reduce pressure

4. Find hidden leaks

Addressing Real LossesWays to reduce leaks

Real Losses

www.efcnetwork.org

1. Respond faster to known leaks• Water leak determination speed?

Listen – leaks cause vibration (sonic and subsonic noise)

Pressure loss

• Staff availability

Staff to respond to leaks

Staff specialized in using necessary

equipment

• Labor, equipment, and materials

Stock repair parts

Contractor contacts

Team with other systems


Real Losses

www.efcnetwork.org

• Track main breaks to find weakest links

• Pipe inventory

Pipe of particular size, age, and material that breaks

in one location likely to break in other similar locations

Oldest pipe is not necessarily the worst pipe

• Budget for timely replacement

2. Asset Management


Real Losses

www.efcnetwork.org

• Reducing pressure reduces leak flow

and the frequency of future water leaks

• Pressure can be reduced by altering

pumps, installing new pressure

reducing valves (PRVs), or changing

existing PRVs

• New PRVs can reduce pressure when

flow is reduced (nighttime)

Photos courtesy Claval

Real Losses3. Reduce Pressure


www.efcnetwork.org

• Leaks that do not surface

Make some noise (sonic and subsonic)

Can flood subsurface areas

May cause cracks in paving or sinkholes

May reduce pressure to customer

Affect operations

• Pumps work harder

• Tanks harder to fill

4. Find Hidden Leaks


Real Losses

www.efcnetwork.org

Technologies for detecting hidden leaks

• Active Listening

• Passive Listening

• Other detection

technologies

Addressing Real LossesFinding hidden leaks

Real Losses

www.efcnetwork.org

Characteristics of leak noiseImpact of pipe size and type

• Small leaks higher frequencies

• Large leaks lower frequencies

• Smaller pipes > Larger pipes

• Metal Pipes > Cement or plastic pipes

• Transitions in pipe materials (clamps and couplings) muffle leak noise


Real Losses

www.efcnetwork.org

• Everyday vibrations (e.g., traffic, HVAC

and electrical equipment) make listening

difficult

• Continuous customer water use

generates similar sound

Characteristics of leak noiseand separating from other noise


Real Losses

www.efcnetwork.org

• Sonic ground listening devices

• Correlators

• Probes

• Walking main lines and listening at valves

Issues

• Time and labor intensive

• Highly skilled staff or contractors

Photo courtesy Texas Water Board

www.fujitecom.com

Active Technology


Real Losses

http://www.fujitecom.com/products/wld.html

www.efcnetwork.org

• Permanent and semi-permanent listening

devices

• Transmits data to central location

• Analyzes night flows

Issues

• Still requires onsite visit to investigate

possible leaks

• Cost

Passive Technology


Real Losses

www.efcnetwork.org

• Tracer Gas Leak Detection

• Sahara, Smartball

Issues

• Works best for a pipe that is out of

service

• Complex and expensive

Additional Technologies


Real Losses

www.efcnetwork.org

• GPR and infrared sensors

• Devices can be inserted into

pipe to locate leaks and the pipe

itself

Issues

• Not suitable in certain regions

• Complex and expensive

Ground

penetrating

radar

Insertion

camera

Additional Technologies


Real Losses

www.efcnetwork.org

Listening stick to

monitor services,

hydrants

What should you have in your toolbox?


Real Losses

www.efcnetwork.org

A ground microphone

that filters and

amplifies sound



Real Losses

www.efcnetwork.org

Budget permitting, a leak noise correlatorespecially if leaks do not surface readily



Real Losses

www.efcnetwork.org

Overnight correlatorsand programmable monitors only recommended when justified economically (factors include high cost of water, chronic leakage, noisy locations)



Real Losses

www.efcnetwork.org

Leak detection strategies


Real Losses

www.efcnetwork.org

• Make contact with elements in system

(hydrants, valves, curb stops) and

listening for acoustic signatures of

leaks

• Done on a periodic basis with

frequency dependent on the

system

• Increase frequency in leak-prone areas

Leak detection survey

Addressing Real LossesLeak detection strategies

Real Losses

www.efcnetwork.org

• Nighttime listening operation implemented to

reduce real water use, noise, traffic

• Nighttime listening operation makes program

costlier and dangerous to surveyor

• Finding sufficient number of contact points can

be challenging in dark

Real Losses

Manned nighttime surveys


www.efcnetwork.org

• There are capable consultants

but results and satisfaction

may vary.

• Internal operation justified

when leaks are frequent and

staff is used at different intervals to

pinpoint leaks

Leak survey issues: Internal vs. external


Real Losses

www.efcnetwork.org

• Allows for better accounting of leak flow and finding

hidden bursts

• Breaking the system into small isolated zones and

monitor flow at minimum flow

time (3 a.m.)

• When a zone has high minimum

flow, surveys can be targeted and

step testing can be used

• DMA zones lend themselves to

better PRVs and lowered leakage

Graphic courtesy of Thames Water

District metering


Real Losses

www.efcnetwork.org

Addressing reported leaks

• Start reporting leaks and breaks

• Repair leaks more quickly

• Develop standards to find, repair and

document leaks and breaks

• Standardize record keeping for leak

location and repair data

• Implement computerized maintenance

management system

• Look at failure trends


Real Losses

Start Here

Work Towards

Here

www.efcnetwork.org

Addressing unreported leaks

Plan, Implement and Improve

a proactive leak detection program

coupled with asset management


Real Losses

www.efcnetwork.org

Address real losses by focusing on leakage

types and the tools to control themUnavoidable Detectable Observable

• Proactive leak detection and repair

• Improve speed of repair

Real Losses

www.efcnetwork.org

• What approaches do you use?

• Is there another approach that might work

better for you?

• What experience have you had with leak

surveys?

Addressing Real LossesDiscussion

Real Losses

www.efcnetwork.org

• Start by getting an estimate of your non-

revenue water

• Then see if you can estimate areas of

authorized unbilled and other losses

• Work to minimize different categories of

loss – it may vary within your system

Addressing Non-Revenue WaterSummary


What type of non-revenue water?

1. Leak on a water main

2. City parks department

3. Fire department use

4. Inaccurate customer meter

5. Theft from a hydrant

6. Unauthorized tap

7. Service line leak

8. Leak in customer’s plumbing (after meter)

Unbilled authorized consumption

Apparent losses

Real losses

www.efcnetwork.org

Identify where water loss could be occurring. Define as unbilled authorized , apparent, or real loss. What would you do to reduce water loss?

Treatment Plant

Addressing Non-Revenue Waterefcnetwork.org/documents/2013/11/waterloss_session-3.pdf · Addressing...

Documents

Transcript of Addressing Non-Revenue Waterefcnetwork.org/documents/2013/11/waterloss_session-3.pdf · Addressing...