FACT SHEET
ASSET MANAGEMENT
BREAKS & LEAKS
What Pipe Breaks & Leaks Reveal
About Pipe Health
QUICK FACTS
• Pipe breaks are a key criterion in pipe
replacement
• Large diameter pipe breaks result, on
average, in a cost to utilities of more than $1
million each
• Total cost of small diameter pipe breaks is
about $10,000 each
• Pipe leakage is a way to assess the system’s
overall condition
• Different pipes have different risk
characteristics
OVERVIEW
When deciding which pipes to replace, many
water utilities consider pipe breaks as an important factor. According to one study, 75% of water
WATER RESEARCH FOUNDATION
utilities cited pipe breaks as a key criterion in pipe
replacement decisions. Other common factors
noted were pipe age (45%), low flows (40%),
condition or type of materials (30%), and need for
pipe size changes (30%) (Kirmeyer, Richards, and
Smith 1994).
WHY REPLACE?
PIPE
BREAKS
75%
PIPE
AGE
45%
LOW
TYPE/ PIPE SIZE
FLOWS CONDITION CHANGE
45%
30%
30%
According to the same survey, the average pipe
break rate for a water utility was between 0.21 to
0.27 breaks per mile of pipeline per year
(Kirmeyer, Richards, and Smith 1994). Another
study cited an average of 0.25 breaks per mile per
year (Grigg 2007).
ASSET MANAGEMENT
BREAKS & LEAKS
1
Pipe breaks in a water distribution system are one
of three critical metrics that can be used to
measure the degree of optimization in the system.
The other two metrics are chlorine residual
(measuring water quality integrity) and pressure
management (measuring hydraulic integrity).
Breaks reflect the physical condition of the distribution system (Friedman et al. 2010).
Although water utilities typically take action to
manage and reduce pipe breaks through monitoring, preventing all pipe failures is impossible.
Water utilities typically manage pipes and their
failures using two distinct categories: largediameter pipe breaks and small-diameter pipe
breaks.
LARGE-DIAMETER PIPE BREAKS
When large-diameter pipe breaks occur, the
consequences are significant (e.g., flooding, major
disruptions of service, city or neighborhood boil
water orders). What constitutes a “large” pipe will
vary from utility to utility, but typically a pipe in the
12-inch and larger to 24-inch and larger diameter
range will be considered a large and critical pipe
by most utilities. As such, water utilities work very
hard to eliminate these types of breaks.
One example of a large-diameter pipe break
occurred with the Massachusetts Water Resources
Authority in 2010. A coupling ring on a largediameter pipe failed, resulting in approximately
two million people being placed on a boil water
order (Stratus Consulting 2011).
WATER RESEARCH FOUNDATION
Total costs (of large pipe
breaks) according to one
recent study ranged from
$6,000 to $8.5 million,
with an average cost of
$1.7 million.
Though large-diameter pipe breaks occur less
frequently than small-diameter pipe breaks, they
are more expensive to repair. Total costs according
to one recent study ranged from $6,000 to $8.5
million, with an average cost of $1.7 million. Direct
costs to water utilities varied from $6,000 to
almost $7.5 million. The largest portion of these
costs (52%) was associated with claims paid
directly by the utility and/or the utility’s insurance
company for property damage (Gaewski and Blaha
2007).
SMALL-DIAMETER PIPE BREAKS
Small-diameter pipes are the most common type
of pipe in a water system and, because they are of
weaker construction that large-diameter pipes,
have more frequent breaks. Water utilities can
manage small-diameter pipe breaks by measuring the frequency of the break rates. This
approach is acceptable given that small-diameter
pipe breaks are typically not catastrophic and the
costs to repair or replace the pipes are generally
relatively low.
Small-diameter pipes often are located in residential or semiresidential areas. When breaks occur,
the pipe can usually be repaired while the system
is in operation, causing minimal or no impact to
customers. If an area must be shut down to allow
for a pipe repair, the affected area is often more
limited than that associated with a large-diameter
pipe break.
The total cost of a typical small-diameter pipe
break for a water utility is estimated at $10,000,
based on limited analyses. These total costs
consist of $5,000 in direct costs to a utility and
$5,000 in indirect costs to society (e.g., traffic
delays or traffic re-routing caused by a break)
(Grigg 2007).
LEAKAGE MANAGEMENT AND DETECTION
Water utilities can use pipe leakage as a way to
help evaluate the condition of the water system,
given that more leakage is often associated with a
reduced physical condition of the system. Leaks
can occur from pipe damage caused by third
parties, corrosion or a few areas of stress in the
pipes, as well as from joints in the distribution
system.
There are two ways in which water utilities can
assess leakage. One way is through conducting a
system-wide water audit, which estimates water
consumption and water loss. The process
enables water utilities to develop performance
indicators to assess water loss, benchmark
themselves with other water utilities, and set
ASSET MANAGEMENT
BREAKS & LEAKS
2
performance metrics (Fanner 2006; Fanner et al.
2007; AWWA 2009, 2010).
REFERENCES
Another way in which water utilities can assess
leakage is through conducting leakage investigations on all or part of the water system, using
dedicated technologies to find the leaks. Many of
these technologies can track the sound of a leak,
allowing the utility to identify the exact point of
the leakage and make repairs (Hughes et al. 2011).
AWWA (American Water Works Association). 2009. Water Audits and Loss Control Programs. 3rd ed.
Manual of Water Supply Practices, M36. Denver, Colo.: AWWA.
PIPE COHORTS
Fanner, P. 2006. Evaluating Water Loss and Planning Loss Reduction Strategies. Denver, Colo.: Awwa
Research Foundation.
A pipe cohort is a group of pipes with similar
characteristics. This concept is helpful in pipe
management, because defining different pipe
cohorts can be helpful in identifying pipes that
have different risk characteristics.
Changes in pipe manufacturing, such as the
introduction of new pipe-making technologies,
are a major criterion when identifying pipe cohort
concerns (e.g., longevity of a pipe and risk of
breakage). For instance, pit cast gray iron pipe and
centrifugally cast gray iron pipe of the same
diameter should likely be considered in different
pipe cohorts, because the significant differences
in manufacturing cause the pipes to behave
differently. Other factors that can affect pipe
longevity and breakage include transportation
and installation methods.
WATER RESEARCH FOUNDATION
AWWA (American Water Works Association). 2010. Water Wiser: AWWA’s Free Water Audit Software
[Online]. Version 4.2. Available:
www.awwa.org/Resources/WaterLossControl.cfm?ItemNumber=48511&navItemNumber=48158. [cited
May 26, 2009]
Fanner, P., R. Sturm, J. Thornton, R. Liemberger, S.E. Davis, and T. Hoogerwerf. 2007. Leakage Management Technologies. Denver, Colo.: Awwa Research Foundation.
Friedman, M., G. Kirmeyer, J. Lemieux, M. LeChevallier, S. Seidl, and J. Routt. 2010. Criteria for Optimized
Distribution Systems. Denver, Colo.: Water Research Foundation.
Grigg, N.S. 2007. Main Break Prediction, Prevention, and Control. Denver, Colo.: Awwa Research
Foundation.
Hughes, D.M., Y. Kleiner, B. Rajani, and J. Sink. 2011. Continuous System Acoustic Monitoring: From Start to
Repair. Denver, Colo.: Water Research Foundation and American Water.
Kirmeyer, G.J., W. Richards, and C.D. Smith. 1994. An Assessment of Water Distribution Systems and
Associated Research Needs. Denver, Colo.: Awwa Research Foundation and American Water Works
Association.
Stratus Consulting. 2011. Multi-Agency Response to a Major Water Pipe Break: A Massachusetts Case Study
and Evaluation, Final Report. Prepared for the Association of Metropolitan Water Agencies, Water
Research Foundation, WaterISAC.
ASSET MANAGEMENT
BREAKS & LEAKS
3