Water Audits & Leaks Detection City of Tigard
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Water Audits and Leak Detection
A Presentation for
Samarinda, Indonesia
October 20-25,2003
International City Managers Association
Resource City Program
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What is a Water Audit?
A step by step procedure to assess the
delivery system.
Identifies how much water is lost(not sold).
Identifies what the loss costs the utility.
Goal of a Water Audit
" Help the Utility Select and Implement
Programs to Reduce
Distribution System Losses"
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What is Leak Detection?
Survey of the distribution system
Identify leak sounds
Pinpoint exact locations of underground leaks
Benefits of a Water Audit
and Leak Detection
4 Reduced water loss
Increased revenue, reduced operation&
maintenance costs
Better system knowledge
Postpones or audits costly capital
improvements
Benefits of a Water Audit
and Leak Detection
a Stretches existing supply to meet growth
Safeguards public health and property
Improves public relations
Reduces legal liability
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Steps of a Water Audit
Task 1 —Measure the supply .
Task 2—Measure authorized metered use
Task 3—Measure authorized un-metered use
°s Task 4—Measure water losses
Task 5—Analyze audit results
After the Audit...
Analyze the value of losses and corrective
measures
a Evaluate corrective measures
Update the audit
Update the master plan
Leak Detection Overview
Visible leaks
Non-visible leaks(underground—use audible
leak detection)
Cost of water loss far outweighs leak
detection costs
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Audible Leak Detection
3 Listening equipment to survey the entire
distribution system
Records suspected areas
Follow up work to pinpoint actual leak
locations
Zone Flow Measurements
Distribution system is"sub-metered" � �
Billing data compared to sub-meter data
o Sub-meter data compared to estimated data
Cost of Leak Detection
m Per American Water Works Association
s In house: $75-$300 per mile of main
Consultant: $150-$500 per mile of main
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Summary
Water audits and leak detection are cost
effective
i They can be done in-house or by a consultant
Leak detection should cost$75-$300 per mile
Industry standard of 15%unaccounted water
Tigard operates near 7%unaccounted water
Not all unaccounted water is due to leaks
Leak detection equipment ranges from$15-
$3000
AWWA manual#36(M36)is an excellent
guide
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