86-0801 Leak Detection Survey August 6, 1986
TO: Mayor and Members of the City Council
FROM: City Manager
SUBJECT : 1986 LEAK DETECTION SURVEY SUMMARY
PURPOSE :
The attached report summarizes leak survey and detection work
that was contracted for in late 1985 and completed early in 1986.
BACKGROUND ;
In an effort to improve the water accountability ratio (quantity
billed divided by quantity pumped ) of the City of Elgin, a leak
survey and detection program of the underground water utilities
was authorized . The work consists of sound surveying areas of
the distribution system and listening for noise indicating a
leak .
Sound level detectors are placed in the water main on both sides
of the leak and a correlator determines the time it takes sound
to travel to each of the detectors. Based on this time and the
known footage between the sound detectors , the location of the
leak is then pinpointed for repair by the distribution crew.
The City of Elgin has 231 miles of underground water utilities
consisting of water mains , valves, and hydrants . A total of 144
miles were sound surveyed and leaks pinpointed under this
contract .
Review of the summary table following the cover letter indicates
that the City of Elgin to date has sound surveyed and leak
detected approximately 308 miles of the distribution system over
the last three years . This means that all of the distribution
system has been surveyed at least once and approximately one-
third has been surveyed twice in the last three years .
Attached is a graph of monthly water accountability ratios a�
well as a 12-month moving average . Review indicates that water
accountability is improving because of the leak detection and
repair program as well as the meter exchange program.
FINANCIAL IMPACT :
The City of Elgin has spent $38,200 for contractual leak survey
and detection work on the distribution system over the last three
years. During this time, costs for leak repair by the City ' s_
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Page Two
construction crew are estimated at $25,000, bringing the total
cost for leak survey, detection, and repair to $63,200. Consi-
dering production costs alone, the estimated annual savings from
recovery of 1 ,239,000 gallons of water at 32 cents per thousand
amount to $144 ,715. Capital improvement costs associated with
increased plant capacity and/or water main size are not taken
into consideration.
RECOMMENDATIONS:
It is recommended that the City of Elgin continue its efforts in
the sound survey and leak detection program until annual costs of
water recovered do not pay for the survey work .
Monies are available in the 1986 budget for additional survey
work , the scope of which is currently being evaluated .
The leaks that were pinpointed during the 1986 survey have been
repaired . Mr . Claus Dunkelberg of Donahue & Associates is here
to answer any questions regarding both the latest leak survey and
detection work and the recommendations contained in their
report .
/ /
I
ty Manager
REZ: jk 305081 . mem
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August 1, 1986
City of Elgin
150 Dexter Court
Elgin, Illinois 60120-5555
Attn: Mayor and City Council
Re: 1986 Leak Detection Survey
Summary Report
Dear Council Members:
Enclosed herewith are fifteen (15) copies of the summary report
for the 1986 Leak Detection Survey which we were pleased to con-
duct in the City of Elgin. Also, one (1) copy of annotated water
system maps showing leakage located and mapping corrections was
given to the water utility. It contains the results of a general
listening survey and follow-up leak location using computerized
correlation equipment.
We wish to express our appreciation for the courtesy and coopera-
tion extended to us by your staff during the survey. It was a
pleasure working with them, and we feel that the results of the
survey were rewarding to all.
Following your review, we would be pleased to receive any ques-
tions you have regarding the enclosed report. We look forward to
working again with the City of Elgin as you continue your efforts
to control unaccounted-for water.
Very truly yours,
DO OHUE & ASSOCIATES, INC.
Jerry S. Kipp, P.E.
Engineer
N
Tom J. Ne edlo
Technician-in-Charge
JSK/pm
cc: Claus Dunkelberg
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LEAK DETECTION
Summary Table
Elgin, Illinois
Survey Miles No. of Leaks Leakage
Year Surveyed Located (GPD)
1983 76 102 157,000
*1984/85 88 65 527,000
1986 144 82 555,000
TOTAL 308 249 1,239,000
* The Leak Survey Contract was started in late 1984 with dis-
trict measurements. Leak detection occurred in 1985.
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CHAPTER 1
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INTRODUCTION AND SCOPE OF PROJECT
INTRODUCTION
The City of Elgin is located in Kane County, Illinois and has a
1980 census population of 63,798 . The water distribution system
is municipally owned and operated and contains approximately 231
miles of water main. The average daily pumpage in the Elgin
water distribution system is approximately 8. 5 million gallons
per day, using 1984 district measurements.
The City of Elgin has had an ongoing water audit/leak detection
program since 1976. The scope of recent surveys included seventy-
six (76) miles of leak detection in 1983, seven district measure-
ments in 1984 and eighty-eight (88) miles of leak detection in
1985. In 1983, 102 leaks were located while 65 were located in
1985.
This report contains the results of the 1986 leak detection sur-
vey, which encompassed approximately 144 miles of main, for the
City of Elgin, Illinois. The City of Elgin undertook this inves-
tigation in a continuing attempt to improve the accountability of
water in the distribution system and reduce operating costs. The
investigation was conducted under the authority of an agreement
between the City of Elgin and Donohue & Associates, Inc.
SCOPE OF PROJECT
The scope of the leak detection survey included the following:
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1. A preliminary listening survey on available appurtenances,
principally valves and hydrants, to identify potential areas
of leakage. Listening points were at intervals no greater
than 400 feet.
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2. A leak location survey using a computer programmed leak
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locator/correlator to pinpoint leak locations.
3. An estimate of the size of each leak located (in gallons per
day) made by an experienced technician.
4. A post repair survey of areas where leaks have been repaired
to detect additional leakage.
5. Preparation of this final report including a map of the area
surveyed, a summary of all leaks discovered and sketches of
all main and service leaks.
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CHAPTER 2
FINDINGS AND RECOMMENDATIONS
FINDINGS
Our findings based on the results of our field investigations are
as follows:
1. Eighty-two leaks were located during this survey,
totaling approximately 555, 000 gallons per day. Repair
of this leakage will result in an estimated annual
savings in water production costs of approximately
$85,000.
2 . The largest number of leaks were located at hydrants,
sixty-one, and accounted for approximately 200, 000 gpd
of leakage. Eighteen of the hydrant leaks were stopped
in the field by tightening the operating nut. The
remaining hydrants are still leaking and require more
extensive repair efforts.
3 . Twelve service leaks accounted for approximately
174,000 gpd of leakage, or 31 percent of total leakage.
4 . Six main leaks were located and accounted for an esti-
mated 175, 000 gpd of leakage of approximately 32 per-
cent of the total leakage located.
5. The remaining leakage occurred at three water main
valves and accounted for 6,000 gpd or 1 percent of the
total leakage.
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6. Corrections to the Elgin Water Distribution System Map
which were discovered during the course of field inves-
tigations are shown on the water system maps included
with this report.
RECOMMENDATIONS
Based on our findings and the results of our field investigations
and engineering analysis, we recommend the following:
1. As the summary table indicates, approximately 302 miles
of water main has been surveyed. The total system has
approximately 231 miles. This would indicate that a
portion of the water system has been leak detected more
than once and further indicates that leakage is a con-
tinuing problem. This is a normal occurrence for all
water systems as they become older. An annual leak
survey aides in controlling leakage thereby minimizing
leakage.
As past reports and this report have indicated, cost
savings realized pay back the cost of the survey and
repair in a short period. An additional cost savings
is realized by postponing plant expansion to meet in-
creased water demands that may be due to uncontrolled
leakage. The cost to expand a plant by one gallon of
capacity is approximately $1.00. This cost saving is
not seen as cash in hand, but as a capital expense that
can be postponed. Plant expansion should occur to meet
rising user consumption. User consumption increases
revenue, which offsets capital expenses, while no
revenue is received due to increased leakage.
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The 1986 survey will pay for itself in less than four
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r months. The survey also provided additional base data
for determining which water mains require replacement.
Repair of the located leakage will provide an addition-
al 555, 000 gpd of water available for consumption that
would not have to be provided for by a plant expansion,
thus postponing a potential $555, 000 capital expendi-
ture for plant expansion.
Therefore, we recommend that an annual leak survey be
continued.
2 . Repair all remaining leakage in the Elgin water dis-
tribution system. Repair should commence on the larger
main and service leaks and then proceed to the hydrants
and valves, with the larger leaks being repaired first.
3 . Hydrant leakage is a continuing problem in Elgin with
43 hydrants still leaking after field investigations
were completed. We recommend that all older style
hydrants be investigated to determine frequency of
repair. A comprehensive replacement program should be
instituted to replace all hydrants which show a great
propensity towards leakage; particularly Ludlow
hydrants.
4 . Because some of the hydrant leakage was stopped or
reduced by tightening the hydrant operating nut, we
recommend the City of Elgin continue to stress proper
methods of operating fire hydrants to anyone who may be
involved with their use.
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5. The cause of main and service leaks should be investi-
gated to determine areas of the of the system which may
require main replacement or a service replacement pro-
gram. Particular attention should be addressed to old
iron and lead services which are more susceptible to
leakage.
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6. The map corrections noted on the maps included with
this report along with any changes that are made to the
Elgin distribution system should be documented on the
master distribution system map.
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CHAPTER 3
FIELD INVESTIGATIONS
Approximately 144 miles of water main were surveyed during March
and April, 1986, for underground leakage in the City of Elgin
water distribution system. This includes all water mains in
Districts one, five, six, and seven along with approximately five
miles of repaving investigations. The quantity of leakage at
each leak was estimated by an experienced technician using, as
indicators, the level and tone of sound created by the leaking
water and the pipe and ground conditions at the leak.
LEAKAGE INVESTIGATIONS
The leak location survey for the City consisted of a preliminary
general listening survey conducted on fire hydrants, system
valves and other system appurtenances, at intervals of 400 feet
or less, throughout the study area. The purpose of this general
listening survey was to detect zones where leakage was occurring.
To pinpoint the leak, a detailed location survey, using a com-
puterized leak correlator, was conducted in those zones which
showed leakage potential. The locations of all leaks identified
during the field investigations are shown on Tables 3-1 through
3-4 and on a copy of the distribution system map which accom-
panies this report. All leak reports are found in Appendix A.
The total leakage located over the 144 miles of water main sur-
veyed is estimated at 555,000 gallons per day. A summary of
leakage located by the by the type of leak is shown on table 3-5.
The highest percentage of leakage, 36 percent, was located at
hydrants and accounted for 200, 000 gallons per day of leakage.
The majority of these leaks were on older style Ludlow hydrants
and cannot be repaired without excavation. Replacement of these
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hydrants with newer style hydrants which are gasketed to help
prevent leakage will greatly reduce maintenance and this program
should be accelerated.
Main leaks accounted for 32 percent or an estimated 175,000 gpd
of total leakage. The cause of main breaks can include surges
from improper operation of hydrants or valves, surges from pump
operations, frost and soil conditions causing movement of the
main, poor backfill or bedding, materials weakened from erosion
and aging or faulty joint material. Causes of main breaks in
Elgin should be investigated. We recommend reviewing main repair
records to look for common causes and to locate those areas of
the system which may require main replacement.
Service leaks accounted for 31 percent or an estimated 174,000
gpd of total leakage. Service leaks usually occur on old lead
and/or galvanized services which are more susceptible to break-
( age. Again, the cause for service breaks should be investigated
to determine if areas of the distribution system are experiencing
an inordinate amount of breaks. Replacing old materials with
newer copper services may be warranted in this case.
TOTAL ANNUAL SAVINGS FROM REPAIR OF LEAKAGE
It is estimated that an annual savings of approximately $85,000
will be realized by the City of Elgin from repair of the leakage
located during the survey. The savings are based on a production
cost of $0.42 per 1000 gallons which includes only the cost of
chemicals to treat the water and electricity for pumpage.
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FUTURE CONTROL OF UNACCOUNTED-FOR WATER
Because control of unaccounted-for water can represent cost sav-
ings and a revenue gain to a utility, it is important that Elgin
continue its efforts to reduce unaccounted-for water. At least
annually, a comparison should be made between metered water sales
and total pumpage to determine the level of unaccounted-for water
and progress being made to reduce unaccounted-for water through
corrective action. Of the estimated 8,500,000 gpd of total pump-
age, 555,000 gpd of leakage has been accounted for by this survey
representing 6.5 percent of the City's total average day pumpage.
Continued leakage investigations should be evaluated annually
based on the cost of locating the estimated system leakage versus
the benefit of reducing annual operating cost by leakage repair.
We recommend that future water audits concentrate on leak detec-
tion of the entire system and testing of large meters. Unless a
cost-effectiveness analysis shows otherwise, we recommend a leak
detection survey of the entire system every year.
Because the two major components of unaccounted-for water are
leakage and meter error, we further recommend that all meters in
the system be tested periodically for accuracy of registration.
Generally we would recommend that meters be tested according to
the following schedule:
Approximate
Diameter Testing Frequency
5/8" to 1" 6 to 10 Y ears
1-1/2" to 3" 2 to 4 years
4" and larger annually
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We recommend focusing attention on the larger meters.
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meters should be tested not only for accuracy of registration,
but also for proper sizing for each application. Although an
improperly sized meter may perform well in a bench test, it may
not be registering accurately in place if it is not sized accord-
ing to the consumers patterns of water use.
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Table 3-1
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Main Leaks By Location
Elgin, Illinois
1986
Estimated
Leak No. Location Leakage (GPD)
23 523 Columbia Avenue 20, 000
49 620/624 Addison Street 25,000
68 86 feet South of North Valve 30,000
at Teft and Forest Avenues
69 Channing St. 48 feet North of 20,000
6" main on Stella Avenue
71 868 Carl Avenue 40,000
107 1484B Todd Farm Drive 40, 000
Total 6 175,000
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Table 3-2 •
Service Leaks by Location
Elgin, Illinois
1986
Estimated
Leak No. Location Leakage (GPD)
15 1162 Preston Avenue 15, 000
16 689 Cooper Avenue 18,000
17 694 Chester Avenue 8, 000
18 425 Campus Drive 8,000
24 523 Hill Avenue 20, 000
50 758 Jay Street 10,000
67 468 Jefferson Avenue 18,000
70 1000 Bellevue Avenue 15,000
72 600 Dixon Avenue 10,000
106 1720 North Lyle Avenue 20,000
108 215 Jackson Street 20, 000
109 425 Hubbard Avenue 12 ,000,
Total 12 174,000
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Table 3-3 •
Hydrant Leaks by Location
Elgin, Illinois
1986
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General Estimated
Leak No. Location Leakage (GPD)
1 Enterprise Street and Hill Avenue 3,000
2 Jefferson Avenue between
Dundee Road and Hill Avenue 5, 000
3 Hill Avenue and Algona Avenue 1,000
4 Lovell Street and Cedar Avenue 5, 000
5 Lincoln Avenue and Logan Avenue 5, 000
6 Lovell Street and St. John Street 3,000
7* Lovell Street and Prospect Road 1,000
8* Lincoln Avenue and Center Road 2,000
9 Congdon aVenue and Bellevue Avenue 1, 000
10 Cooper Avenue and Logan Avenue 3,000
11 Spring Street and River Bluff Roadq 5,000
t12 Cooper Avenue and Prospect Blvd. 8,000
13 U.S. Route 20 - 2 Hydrants west
of system 5,000
19 Stewart Avenue and Trout Road 1,000
20 Jefferson Avenue and Hill Road 1,000
25* Rugby Place and DuPage Street 2 , 000
26* Jay Street and Grace Street 2,000
27* Preston Avenue and Forest Avenue 3,000
28 Bent Street and Cleveland Avenue 1,000
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General Estimated •
rLeak No. Location Leakage (GPD)
29* Illinois Avenue and Homeland Avenue 3, 000
30 Elgin Avenue and LaVoie 2,000
31 Illinois Avenue and Bluff City Blvd. 10, 000
32* Illinois Avenue and Dwight Avenue 2,000
r 33 Hastings Street and Illinois Avenue 1,000
34 Hammond Avenue and Elizabeth Street 3,000
35 Bluff City Blvd. and Peck Place extd. 3,000
36 Easternmost Hydrant on Bartlett Road 5,000
38* Hill Street and Division Street 3,000
39 Division Street and Hilton Place 2,000
40 North Street between Channing Street
and Hill Street 1, 000
C41 Gifford Street and Hickory Place 3,000
r42 Healy Street and Barrett Street 5, 000
43* Gifford Street and Fulton Street 1,000
44* Regent Street and Bowen Court 3,000
45* Raymond Street and May Street 4,000
46 Watch Street 300 feet west of
Raymond Street 5,000
47 Summit Street and Hiawatha Drive
in front of True Value Store 10,000
C48* Slade Avenue and River Bludff Road 1,000
51 Franklin Blvd. and Spring Street 4,000
52 Franklin Blvd. and Center Street 10, 000
53 Academy Place and Kimball Street 3, 000
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General Estimated .
Leak No. Location Leakage (GPD)
54 Villa Street and Healy Street 3,000
r55 St. Charles Street and Bent Street 1,000
56 Liberty Street and Oakland Avenue 1, 000
57 Liberty Street north of Barrett Street 5,000
58 Illinois Avenue and Laurel Street 5,000
59 Villa Street (Lake St. ) west of
Willard Avenue 4, 000
60 Illinois Avenue and Sherman Avenue 2,000
61 Bluff City Blvd. and Raymond Street 3,000
62 1050 Bluff City Blvd. 3,000
63* Grove Avenue and Summit Street 2,000
64* Daniels west of Grove Avenue 3 ,000
65* Shiloh Lane west of Waverly Drive 1,000
66* Varsity Drive and Maroon Drive 4,000
100* Worth Avenue and High Street 4,000
r101* Worth Avenue and Oakley Avenue 1,000
102 Highland Avenue and Alfred Avenue 2,000
103 436 Alfred Avenue 5,000
104 2200 Highland Avenue 5,000
105 Parkview Drive and Century Oaks Dr. 4 ,000
Total 61 200,000
* Leak repaired by tightening nut on hydrant.
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Table 3-4
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Valve Leaks by Location
Elgin, Illinois
1986
Estimated
Leak No. Location Leakage (GPD)
14* 6" valve to north at Lucille
Avenue and Willard Avenue 1,000
22 River Bluff Road west of Spring
Street Drip
37 West valve at Maaroon Drive and
Lovell Road 5,000
Total 3 6,000
* Leak repaired by field crew.
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Table 3-5
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Leakage Summary by Type of Leak
Elgin, Illinois
1986
Total
Type of Number of Estimated
Leak Leaks Leakage (GPD)
Main 6 175,000
Service 12 174,000
Hydrant 61 200,000
Valve 3 6,000
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Total 82 555,000
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