leak detection
931-289-2300
A PRACTICAL APPROACH TO
WATER AUDITS AND
LEAK DETECTION
Presented By:
R
RYE ENGINEERING PLC
Consulting Engineers & System Operators
Friday, March 15, 2013
Leak Detection Services
RYE ENGINEERING PLC
Consulting Engineers & System Operators
4210 West Main Street
Erin, TN 37061
Phone: (931) 289-2300
Fax (931) 289-2313
Experience and Qualifications
Mike Sheppard, Senior
Project Manager
• Water Distribution
Manager CGW (Retired)
• 35+ Years of Experience
• Utility and Construction
Background
Why is Leak Detection Important?
TN Comptroller’s Office
• After January 1, 2013
• All Water Audits in AWWA
Format
• Reduce “REAL LOSSES”
AWWA Water Balance
Figure 1. IWA/AWWA Water Balance (All data in volume for the period of reference, typically one year)
Billed Authorized
Consumption
Authorized
Consumption
System Input
Volume (corrected
for known errors)
Unbilled
Authorized
Consumption
Apparent Losses
Billed Metered Consumption
(including water exported)
Revenue Water
Billed Unmetered Consumption
Unbilled Metered Consumption
Unbilled Unmetered
Consumption
Unauthorized Consumption
Customer Metering Inaccuracies
Systematic Data Handling Errors
Leakage on Transmission and
Distribution Mains
Water Losses
Real Losses
Leakage and Overflows at
Utility's Storage Tanks
Leakage on Service
Connections up to point of
Customer metering
Non-Revenue
Water (NRW)
Real Losses
Apparent
Losses
Unauthorized Consumption
Customer Metering
Inaccuracies
Systematic Data Handling
Errors
Leakage on Transmission
and Distribution Mains
Water Losses
Real Losses
Leakage and Overflows at
Utility's Storage Tanks
Leakage on Service
Connections up to point of
Customer metering
Real Losses
Water Main Leakage
Service Line Leakage
Apparent Losses Encountered
Apparent
Losses
Unauthorized Consumption
Customer Metering
Inaccuracies
Systematic Data Handling Errors
Practical Approach to Water Audits
• Useful in Before Leak Detection
• TOP DOWN Approach
• Pre-Audit Survey – Not Perfect
Who Can Help with Water Audit?
• TAUD – Classes, Circuit Riders
• Engineering Consultant
• Leak Detection Consultant
Why Perform a Water Audit?
A. Because Comptroller says so
B. It’s the law
C. It may actually be useful
D. All of the above
How Can a Water Audit Help with
Leak Detection?
• Quantifies Leakage
• Calculates Realistic Leakage Reduction
Goals
• Answers: Is leak detection worth it?
What Type of Audit Should I Do?
• TOP DOWN WATER AUDIT
• Use AWWA Software
• AWWA M-36
TIPS for TOP DOWN initial AUDIT
• Keep it simple
• Don’t search endlessly for data
• Set a time deadline (1/2 day)
TIPS for TOP DOWN initial AUDIT
• Pull out last financial annual audit
• Get out your latest water loss calculation
sheet from old method
• Use information from the same FY
• GET STARTED!
What Information is Needed for a
Quick, Top Down, Water Audit?
1. Distribution System Information
2. Financial Data
3. Operational Data
4. Water Balance Inputs
Distribution System Information
• Miles of Transmission Main
• Number of Service Connections
• Average Operating Pressure
Financial Data
• Total Costs to Operate Water System ($)
• Retail Water Rate ($ per MG)
• Cost to Produce Water ($ per MG)
Water Balance Inputs
MAJOR COMPONENTS
• Water Produced from WTP
• Water Purchased
• Water Billed and Metered to Customers
Water Balance Inputs
Other Components
DON’T GET HUNG UP ON THESE
• Unbilled Authorized Consumption
- Flushing, Fire Dept, Gov’t uses, etc.
• Validities – Calibration Schedules, etc.
Water Balance Inputs
Minor Components
DON’T GET HUNG UP ON THESE either
• Adjustment for Meter Error (if known)
• Adjustment for Tank Level Difference (1st Day vs. Last Day of Year)
• Other Adjustments
Water Balance Inputs
Apparent Losses –
• Mistakes, Inaccuracies
• NOT LEAKS
• Most Important = Meter Inaccuracies
Water Balance Inputs
Let’s look at the AWWA Audit Software…….
Southern Middle TN Community Example
Water System - BEFORE LEAK
DETECTION.xlsx
What Outputs are Useful for Leak
Detection?
• NRW – Non-Revenue Water
• CARL – Current Annual Real Losses
• UARL – Unavoidable Annual Real Losses
• ILI – Infrastructure Leakage Index
NRW
Non-Revenue Water
• Don’t Say “Unaccounted For Water”
ANYMORE!
• NRW by % of Supply - Traditional
• NRW by % of Operating Costs –
REPORT TO COMPTROLLER
Non-Revenue Water
Figure 1. IWA/AWWA Water Balance (All data in volume for the period of reference, typically one year)
Billed Authorized
Consumption
Authorized
Consumption
System Input
Volume (corrected
for known errors)
Unbilled
Authorized
Consumption
Apparent Losses
Billed Metered Consumption
(including water exported)
Revenue Water
Billed Unmetered Consumption
Unbilled Metered Consumption
Unbilled Unmetered
Consumption
Unauthorized Consumption
Customer Metering Inaccuracies
Systematic Data Handling Errors
Leakage on Transmission and
Distribution Mains
Water Losses
Real Losses
Leakage and Overflows at
Utility's Storage Tanks
Leakage on Service
Connections up to point of
Customer metering
Non-Revenue
Water (NRW)
CARL
Current Annual Real Losses
• Total Water Leaking from System (MG)
• Calculated Value (not input data)
• CARL/day or CARL/minute – gpm
UARL
Unavoidable Annual Real Losses
• May we call him “Earl”?
• Leakage that cannot be reasonably
eliminated (MG)
• “U Are Really Low”
UARL
Unavoidable Annual Real Losses
• UARL/day or UARL/minute – gpm
• Target Number?
The CARL and UARL Relationship
• CARL and UARL are brothers
• We are parents
• UARL is perfect
• CARL is not
• Our Goal: CARL to be more like UARL
ILI
Infrastructure Leakage Index
• CARL divided by UARL
• ILI = 1 is the best we can hope for
• If ILI = 10 then we are leaking about 10
times what we should be
Operational Indicators
Useful in Leak Detection
• Let’s look at AWWA Audit Software…..
Southern Middle TN Community
Example Water System - BEFORE
LEAK DETECTION.xlsx
Financial Indicators Justifying Leak
Detection
Annual Cost of Real Losses
• How much are my leaks costing
me?
• If Annual Cost of Leak Detection and
Repair is less than Annual Costs of
Real Losses, then is it justified?
Financial Indicators Justifying Leak
Detection
Let’s look at AWWA Audit Software….
Water Balance Inputs
Let’s look at the AWWA Audit Software…….
Southern Middle TN Community Example
Water System - BEFORE LEAK
DETECTION.xlsx
After the TOP DOWN Audit
• If Audit Justifies Leak Detection
• What’s next?
• Practical Approach to Leak Detection
Practical Approach to Leak
Detection
1. Meet and Listen
to Utility Staff
2. Investigate
System
3. Acoustic Leak
Detection
Utility Staff Meeting
Questions
1. Can a map of distribution system and
sewer system be provided?
2. How much water are we looking for?
3. From Audit: CARL-UARL = ____ gpm
Effect of the Size of Distribution System
on Water Loss
¼” dia = 15,000 gallons/day
(625 GPH, 10 GPM)
System #1: 50,000 GPD
usage
•Results in a 30% water loss
Effect of the Size of Distribution System
on Water Loss
¼” dia = 15,000 gallons/day
(625 GPH, 10 GPM)
System #2: 3 MGD usage
•Results in a 0.5% water
loss
Leak Estimation Chart (60 PSI)
Pipe Leak
Size
1/16”
1/8”
3/16”
1/4”
Approximate
Approximate Approximate
Gallons
Gallons
Gallons
Lost/Month
Lost/Day
Lost/Month
x 5 Leaks
360
11,000
55,000
3,100
96,000
480,000
8,400
260,000
1,300,000
15,000
465,000
2,300,000
Value of a Leak
50 GPM = 3,000 GPH = 72,000 GPD =
2,160,000 Gallons Per Month =
$6,480 (@$3.00/thousand gallons/month)
Utility Staff Meeting
Questions
4. Has there been a gradual increase in
water loss?
5. Has there been a large increase recently
in water loss?
6. What failures have been found within the
distribution system?
Distribution System Failures
Service line failures: polyethylene,
galvanized, copper;
Service Line Failures
1.0 Million Gallon/Month Leak
($3000/Month)
IMG_1268.MOV
Main Lines
IMG_1272.MOV
Distribution System Failures
Main line failures: PVC, cast iron, galvanized.
Utility Staff Meeting
Questions, cont’d
7. What soil types are present?
a. Limestone;
b. Red clay;
c. Sand;
d. Sink holes.
Sink Hole
Sink Hole
Sink Hole
Sink Hole
Investigate the System
1. Sewer System
a. Check manholes
b. Check flow between manholes
c. Compare water usage of sewer
customers v. water metered to sewer
plant
Investigate the System
2. Storm Drainage
a. Catch basins
b. Monitor where drainage spills out
Investigate the System
3. River Crossings
4. Cross Country Lines
5. Examine areas that are not visible on a
daily, weekly, or monthly basis.
6. Meter Boxes – Automatic Read
Acoustic Leak Detection
1. Start in older sections of system
(downtown area)
2. Work outwards to newer areas
3. Daily Leak Log
Acoustic Leak Detection
Acoustic Leak Detection
Acoustic Leak Detection
Billing for Leak Detection
1. By the Mile
2. By the Hour
By the Mile
Based on length of water main surveyed
Pros and Cons:
1. Pro: Fixed Price (Easy to Budget)
2. Con: Unknown Conditions in System
By the Hour
Based on time required to survey system
Pros and Cons:
1. Pro: Promotes thoroughness
2. Pro: Can be less expensive with
Utility’s assistance
3. Con: Price is Variable (Hard to Budget)
Assistance from the Utility
1. Provide an employee
a. Familiar with all meter locations
b. Cuts time by 1/2 +/-
c. Much time spent looking for meters
Assistance from the Utility
2. Pre-mark listening points
a. Paint / flag meters
b. Paint arrows in road
c. Can be done by meter reader
Manual Acoustic Leak Detection
Vs.
Correlators
1. Ground microphone – FCS X-Mic
2. PVC and Correlators – Sound conductivity
3. Listening on polyethylene / PVC services
• Short distances
Manual Acoustic Leak Detection
4. Main line PVC leaks:
a. Ground microphone
b. Direct position over main
c. Detector tape
5. Copper services - metallic
Manual Acoustic Leak Detection
6. Alternate methods:
a. Valve pinch off
b. Monitor low use times
Results
1. New Factory built in
Clarksville: New 16” DI
line – 2000 L.F.
• Contractor: $40,000
on correlators
• Contractor: 2 weeks
spot digging
• Rye Engineering: 3
hrs-LEAK FOUND
Results
2. Northern KY
town located on
Ohio River
• Approx. 4
weeks of leak
detection
• 3.3 million
gallons/month
water loss
detected
Results
3. Cumberland River
Community
• 3 days of leak
detection
• A savings of
600,000
gallons/month
Results
4. Western
Montgomery
County
• 6 weeks of
leak detection
• Savings of 2
million
gallons/month
Results
5. Tennessee River
community
• 2 days of leak
detection
• Found one 6”
main line split
and one ¾”
service
Results
6. Clarksville
Housing
Authority (120
units)
• 5 days of leak
detection
• A savings of
432,000
gallons/month
7. Large rural
system in
Macon County
• 1 month of
leak
detection
• Reduced
leakage
from 54% to
15%+/-
Results
Results
8. West TN City
near Mississippi
River
• 2 days of leak
detection
• With only
partial survey
reduced to
under 20%
leakage
CASE STUDY
9. Southern Middle TN Community
• Non-Revenue Water = 46% +/- by
Volume
• CARL= 103 MG/year
• CARL / min = 198 gpm* = Leakage+/•
*Utility estimated165 gpm+/- of its flow was being lost due to
leakage in March 2013
CASE STUDY
Well Prepared Utility
• Zone Meters in Place
• Isolated Leak to Downtown Area
• Narrowed Search: 30 mi down to 10 mi
CASE STUDY
• 2-1/2 Days of Acoustic Leak Detection
• Real Losses Found = 110 gpm – 150gpm
• 13 Total Leaks – All Service Lines
• REPAIRS MADE DURING LEAK SURVEY
Types of Leaks
Types of Leaks
Repairs
Repairs
Leaks Found
Leaking Into Sewer
Goes with Audio.MOV
Leaks Found
Goes with Audio - 1.MOV
Leak Sound - Faint
Goes with Audio 0.MOV
Sound of a Leak - Loud
Goes with Audio 1.MOV
Leaks Found
gusher again.MOV
Leaks Found
Service Line Leak with Pump Out.MOV
After Leak Detection
• Re-run Audit Software (for Leak Detection
Purposes Only)
• Use Master Meter to Estimate Reduction in
Real Losses (extrapolate for 1-year)
• Quantify Results and Compare with Before
• Importance of Repair and Maintenance
Quantify Results with AWWA
BEFORE Leak Survey
AFTER Leak Survey
UARL =
20 MG/Year
UARL =
20 MG/Year
CARL =
103 MG/Year
CARL =
26 MG/Year
ILI =
5.2
ILI =
1.3
NRW (vol)=
46%
NRW (vol)=
20%
NRW ($) =
20%
NRW ($) =
7%
Real Losses= $190,000/YR
Real Losses= $49,000/YR
Re-run Audit Software
• Let’s go to the AWWA Audit Software…
Southern Middle TN Community Example
Water System - PROJECTIONS AFTER
LD.xlsx
Audit Phenomena
• Use the Audit Software to try what-ifs
• Does it encourage higher operating costs?
• How can a system with NRW = 46% (vol)
not be in violation?
• What to do with the money saved?
What can you do with Money
Saved?
• Spend?, Invest?, Save?
• Replace Lines?
• Replace Services?
• Timeliness
Pros and Cons of Purchasing Your
Own Leak Detection Equipment
• Cost of Equipment
• Dedicated Employee(s) Cost
• Training
• Shelving It!
The Human Elements of Leak
Detection
• It’s the Person – Not the equipment
• Experience in Water Distribution Systems
• Not just “Technicians”
• Grabbing the Low Hanging Fruit
THANK YOU!
Leak Detection Services
RYE ENGINEERING PLC
Consulting Engineers & System Operators
4210 West Main Street
Erin, TN 37061
Phone: (931) 289-2300
Fax (931) 289-2313
leak detection
931-289-2300