EPA/600/JA-02/406
2002
COSTS FOR WATER SUPPLY DISTRIBUTION SYSTEM REHABILITATION
By Ariamalar Selvakumar1, Robert M. Clark2, and Mano Sivaganesan3
Abstract: There is growing concern over the need to rehabilitate, replace and repair
drinking water distribution systems and wastewater collection systems in the United
States. A recent survey conducted by the United States Environmental Protection
Agency (U.S. EPA) found that $138 billion will be needed to maintain and replace
existing drinking water systems over the next 20 years. It is estimated that $77 billion of
this expenditure will be dedicated to repairing and rehabilitating pipelines. Given the
cost and disruption caused by replacing distribution system pipe using conventional
open trench technology, utilities are beginning to increase the application of
rehabilitation or trenchless replacement technologies to extend the life of existing pipes.
This paper discusses the various types of technologies that can be used for
rehabilitation and repair of drinking water distribution components. It also presents
representative costs that can be used by utility managers to estimate order-of-
magnitude budgetary costs for rehabilitation and replacement of distribution system
components.
1 Environmental Engineer, Urban Watershed Management Branch, Water Supply
and Water Resources Division, National Risk Management Research Laboratory, U.S.
Environmental Protection Agency (MS-104), Edison, New Jersey 08837. E. mail:
selvakumar.ariamalar@epa.gov
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2 Senior Research Engineering Advisor, National Risk Management Research
Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268
3 Mathematical Statistician, Office of the Director, Water Supply and Water
Resources Division, National Risk Management Research Laboratory, U.S.
Environmental Protection Agency, Cincinnati, Ohio 45268
Keywords: Water Distribution System, Rehabilitation, Replacement, Pipe, Cost,
Lining, Trenchless Replacement, Open-Trench Replacement, Excavation
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INTRODUCTION
There is growing concern over the need to rehabilitate, replace and repair
drinking water distribution systems and wastewater collection systems in the United
States. Water distribution systems and wastewater collection systems represent major
investments by municipalities. Because of the potential public health and safety
implications of an inadequate water and wastewater system, maintaining these systems
in good condition is an extremely important responsibility. This is particularly true with
regard to the maintenance and repair of drinking water distribution systems.
In the U.S., 24% of the waterborne disease outbreaks reported in community
water systems over the past decade were caused by contamination entering the water
distribution system, i.e., not due to poorly treated water (Clark et al. 1998). For
example, in Cabool, Missouri, during the period of December 15, 1989 to January 20,
1990, residents and visitors (population 2,090) experienced 240 cases of diarrhea and
six deaths. An investigation concluded that the illness was caused by waterborne
contaminants that entered the distribution system through a series of line breaks and
meter replacements (Geldreich et al. 1992).
Of the approximately 200,000 public water systems in the United States, about
30% are community water systems that serve primarily residential areas and 90% of the
population. There are approximately 863,000 miles (1,380,800 km) of distribution
system in the United States with an annual rate of new installations estimated at 11,900
miles (19,040 km) and annual replacement rate estimated at 4,100 miles (6,560 km)
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(based on extrapolation from American Water Works Association data) (AWWA 1992,
1998). A survey conducted by the U.S. EPA found that $138 billion will be needed to
maintain and replace existing drinking water systems over the next 20 years with 56%
($77 billion) of this dedicated to pipelines (U.S. EPA 1997; Heavens 1997).
This paper presents representative costs that can be used by utility managers to
estimate order-of-magnitude budgetary costs for rehabilitation and replacement of
distribution system pipelines. Cost data were acquired from personnel who have
experience in rehabilitation, contact with manufacturers and construction contractors,
and articles that appeared in journals and conference proceedings. This cost data is
considered accurate enough for preliminary planning and budgetary purposes. This
should not be considered to be a construction cost estimate for performing a certain
rehabilitation/replacement technology. Actual cost information should be obtained from
local contractors. The cost of rehabilitation and replacement is a function of a number
of factors such as total length of the project; pipe diameter; product pipe; obtaining
access to the pipe; cleaning prior to lining application; excavation of insertion and
receiving pits; pavement removal/replacement above the access pits; removal and
replacement of existing valves, fire hydrants, and other contingent work; bypass piping
and connections to existing services; and other items such as traffic control, removal of
obstruction, etc.
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WATER DISTRIBUTION SYSTEM PIPE PROBLEMS
Water distribution pipe problems can be addressed through either rehabilitation
or trenchless or open-cut replacement. Rehabilitation is defined as improvement of the
functional service of an existing pipeline system by lining the interior. It involves placing
a water tight surface inside of an existing pipe without requiring extensive excavation of
the soil. Replacement means installing a new pipeline without incorporating the existing
pipeline by either open cut or trenchless replacement. Both rehabilitation and
trenchless replacement reduce the amount of excavation required to repair pipe, but
neither eliminates it completely. Typical costs for these technologies are summarized in
Table 1.
WATER DISTRIBUTION SYSTEM REHABILITATION METHODS
Pipeline rehabilitation methods use the existing pipe either to form part of the
new pipeline or to support a new lining. Rehabilitation is proceeded by cleaning the
pipe to remove scale, tuberculation, corrosion, and other foreign matter. Linings, to be
effective, must make intimate contact with the pipe surface. Proper surface preparation
significantly affects the strength and bonding of lining (Ashton et al. 1998). These
methods can be divided into two categories: nonstructural and structural.
Nonstructural Lining
Nonstructural lining involves placing a thin coating of corrosion-resistant material
on the inner surface of the pipe. The coating is applied to prevent leaks and increase
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the service life. However, coating does not increase the structural integrity of the pipe.
The only coatings considered as proven techniques for water distribution pipes are
cement mortar and epoxy.
Cement Mortar Lining
Cement mortar linings are unique, because they are porous. Corrosion
protection is achieved by the development of a highly alkaline environment within the
pores, which is a result of the production of calcium hydroxide during cement hydration.
Cement mortar is applied using a variety of equipment, depending on pipe size and
overall project length. Access to the pipeline is accomplished by excavation and
removal of a length of pipe. The thickness of the lining varies with pipe diameter and
type of pipe and varies from 1/8 inch (0.3 cm) for 4-inch (10.2-cm) diameter pipes to %
inch (1.3 cm) for 60-inch (152.4-cm) diameter pipes. Water mains from 4 inches (10.2
cm) to 60 inches (152.4 cm) in diameter have been rehabilitated by cement mortar lining
techniques. It has a useful life in excess of 50 years. It can significantly improve the
Hazen-Williams coefficient of pipe friction, C (Deb et al. 1990).
Epoxy Lining
Epoxy resin lining of water mains is an alternative to cement mortar lining. It has
not been widely used in U.S. However, it has been practiced in several countries
including United Kingdom and Japan. In the United Kingdom, epoxy lining competes
with cement mortar lining for pipe sizes 4 inches (10.2 cm) to 12 inches (30.5 cm) with
respect to price (Conroy et al. 1995). Epoxy lining has an estimated life in excess of 75
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years (Watson 1998). The lining thickness for epoxy as practiced in the industry is only
0.04 inches (1 mm) regardless of the pipe size, which minimizes the impact of diameter
reduction on smaller pipes.
Structural Lining
Structural lining involves placing a watertight structure in immediate contact with
the inner surface of a cleaned pipe. A variety of technologies including sliplining, cured-
in-place pipe, fold and form pipe, and closed-fit pipe lining are available. This is the only
rehabilitation technique that improves structural integrity of a pipe.
Sliplining
Sliplining is the oldest rehabilitation method. In this process a new pipeline of a
diameter smaller than the pipe being repaired is inserted into the defective pipe and the
annulus grouted. It has the merit of simplicity and is relatively inexpensive, but there is
a reduction in flow capacity (35% to 60%) depending upon pipe size (Spero 1999).
Sliplining is applicable to mains with diameters ranging from 4 to 108 inches (10.2 to
274.3 cm) (Spero 1999). The most commonly used material for sliplining are high
density polyethylene and fiberglass reinforced polyester. Excavation is required for
insertion and receiving pits. All service connections, valves, bends, and appurtenances
must be individually excavated and connected to the new main.
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Cured-ln-Place Pipe
Cured-in-place pipe (CIPP) involves placing a fabric tube impregnated with a
thermosetting resin that hardens into a structurally sound jointless pipe when exposed
to hot circulating water or steam into a cleaned host pipe using the inversion process
described below. Access to the pipeline is accomplished by excavation and removal of
a length of pipe. There is no reduction in flow capacity. However, the flow must be
completely stopped or by passed during installation and curing. All service connections,
valves, bends, and appurtenances must be individually excavated and connected to the
new main.
Insituform Technologies®, Inc. offers a range of solutions in North America for
rehabilitating water mains (Oxner and Allsup 1998). It has a design life which exceeds
50 years (TTC Technical Report 1994).
Fold and Foam Pipe
Fold and form pipe (FFP) utilizes thermoplastic materials (PVC or PE) which is
heated and deformed at the factory from a circular shape to a "U" shape to produce a
net cross-section that can be easily fed into the pipe to be rehabilitated. The FFP is fed
from a spool into the existing pipe where hot water or steam is applied until the liner
gets heated enough to regain its original circular shape and create a snug fit within the
host pipe (Spero 1999). All service connections, valves, bends, and appurtenances
must be individually excavated and connected to the new main. Excavation is required
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for insertion and receiving pits. It has a design life of greater than 50 years. Fold and
form is applicable to mains with diameters ranging from 8 to 18 inches (20.32 to 45.72
cm) (Spero 1999).
Close-Fit Pipe
Close-fit pipe lining involves pulling a continuous lining pipe that has been
deformed temporarily so that its profile is smaller than the inner diameter of the host
pipe. This lining method is often referred to as the modified sliplining approach. Close-
fit pipe lining makes use of the properties of PE or PVC to allow temporary reduction in
diameter and change in shape prior to insertion in the defective pipe.
As with sliplining, excavation is required for insertion and receiving pits. All
service connections, valves, bends, and appurtenances must be individually excavated
and connected to the new main. Close-fit pipe has a design life of greater than 50
years. This method has been used for pipes with diameters ranging from 2 to 42 inches
(5.1 to 106.7 cm) (Heavens 1997).
WATER DISTRIBUTION SYSTEM REPLACEMENT METHODS
Replacement of pipelines can be accomplished by using either trenchless or
open-trench techniques. Cost information on these technologies is summarized in
Table 1.
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Trenchless Replacement
Trenchless replacement involves inserting new pipe along or near the existing
pipe without requiring extensive excavation of soil. Trenchless replacement can be
done with minimal disruption to surface traffic, business, and other activities, as
opposed to open trenching. There is a significant reduction of the social costs
associated with construction. The best known trenchless replacement techniques are
pipe bursting, microtunneling, and horizontal directional drilling.
Pipe Bursting
Pipe bursting was developed and licensed by British Gas about 16 years ago. It
is a method for replacing pipe by bursting from within while simultaneously pulling in a
new pipe. The method involves the use of a static, pneumatic, or hydraulic pipe
bursting tool drawn through the inside of the pipe by a winched cable, with the new pipe
attached behind the tool. The bursting tool breaks the old pipe by applying radical force
against the pipe and then pushes pipe fragments into the surrounding soil. The liner
pipe can be the same size or as much as two pipe sizes larger than the existing pipe.
Excavation is required for insertion and receiving pits.
Pipe bursting has been used to replace pipes with diameters ranging from 6 to 48
inches (15.2 to 121.9 cm). The liner pipes are normally PE or PVC.
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Microtunneling
Microtunneling involves the use of a remotely controlled, laser-guided, pipe-
jacking system which forces a new pipe horizontally through the ground. This
trenchless method is used for constructing pipelines to close (±1 inch or ±2.54 cm)
tolerances for line and grade. This method can be cost-effective compared to open-cut
construction when pipelines are to be installed in congested urban or environmentally
sensitive areas, at depths greater than 15 feet (0.6 m), in unstable ground, or below the
water table. Microtunneling can be used in variety of soil conditions from soft clay to
rock, or even when there are boulders to deal with. It can be used at depths of up to
100 feet (30.48 m) below the water table without dewatering. Types of pipes that can
be installed include concrete, steel, PVC, clay, and fiberglass-reinforced pipe. It is
applicable to mains with diameters ranging from 18 to 72 inches (45.7 to 182.9 cm).
Horizontal Directional Drilling
Horizontal directional drilling (HDD) consists of a rig that makes a pilot bore by
pushing a cutting or drilling head that is steered and guided from the surface. Drilling
fluid is pumped through the drill/push rods and displaces the cut soil. When the pilot
bore is completed, pulling back a reamer enlarges the hole. Progressively larger back-
reamers are used until the hole is large enough to pull in the pipe. HDD is applicable to
mains with diameters ranging from 2 to 60 inches (5.1 to 152.4 cm) (Spero 1999).
Types of pipes that can be installed include PVC, PE, steel, and copper. HDD is
suitable for installing pipes under waterways, major highways, and other obstacles.
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Open-Trench Replacement
Open-trench replacement is the most commonly used method for replacement of
water mains. It involves placing new pipe in a trench cut along or near the path of the
existing pipe. Open-trench replacement is cost intensive and is plagued with the
expected problem of working within developed areas where pipes may be beneath
streets, sidewalks, customer landscapes, utility poles, etc. There are two basic types of
open-trench replacement: (1) conventional; and (2) narrow. The conventional open-
trench method uses the same approach as that used to place new pipe. The narrow-
trench replacement method is similar to conventional open-trench method, but the
trench width is kept to the absolute minimum possible. It is primarily used for installing
polyethylene pipes (Morris 1996).
SUMMARY AND CONCLUSIONS
This paper presents representative costs that can be used to estimate the order-
of-magnitude costs for rehabilitation and replacement of distribution system pipelines.
The costs given in this paper only address the base installation costs of
rehabilitation/replacement technologies. A series of separate additive items should be
added to the base installation cost to get the total cost. The additive items are removal
and replacement of existing valves, fire hydrants, and other contingent work, traffic
control, utility interference, removal of obstruction, and bypass piping and temporary
service connections to existing services.
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APPENDIX 1: References
American Water Works Association. (1992). 1992 Water Industry Database. AWWA,
Denver, CO.
American Water Works Association. (1998). 1998 Water Industry Database. AWWA,
Denver, CO.
Arthurs, D. (1999). "Personal Communication on Unit Cost of Swagelining." ARB,
Swagelining Licensee, CA.
Ashton, C. H., Hope, V. S., and Ockleston, J. A. (1998). "The Effect of Surface
Preparation in the Repair of Pipes." Paper presented at the Proceedings of the
International Conference on Rehabilitation Technology for the Water Industry, Lille,
France.
Boyce, G. M., and Bried, E. M. (1998). "Social Cost Accounting for Trenchless
Projects." Proceedings of the Conference entitled North American No-Dig' 98,
Albuquerque, NM.
Clark, R. M., Tafuri, A. N., Yezzi, J. J., Haught, R. C., and Meckes, M. C. (1998).
"Urban Drinking Water Distribution Systems: A U.S. Perspective." Proceedings of the
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Conference entitled Regional Water System Management: Water Conservation, Water
Supply and System Integration, held in Valencia, Spain.
Conroy, P. J. (1990). "The Effects on Water Quality Arising from In Situ Cement
Lining." WRc Publications, Medmenham, England.
Conroy, P. J., Hughes, D. M., and Wilson, I. (1995). "Demonstration of an Innovative
Water Main Rehabilitation Technique: In Situ Epoxy Lining." AWWA Research
Foundation, Denver, CO.
Deb, A. K., Snyder, J. K., Chelius, J. J., and O'Day, D. K. (1990). "Assessment of
Existing and Developing Water Main Rehabilitation Practices." AWWA Research
Foundation, Denver, CO.
Geldreich, E. E., Fox, K. R., Goodrich, J. A., Rice, E. W., Clark, R. M., and Swerdlow, D.
L. (1992). "Searching for a Water Supply Connection in the Cabool, Missouri Disease
Outbreak of Escherichia coli 0157:H7." Water Res. 26(8), 1127-1137.
Gumerman, R. C., Burris, B. E., and Burris, D.E. (1992). "Standardized Costs for
Water Distribution Systems." EPA/SW/DK-92/028, Risk Reduction Engineering
Laboratory, Office of Research and Development, U.S. Environmental Protection
Agency, Cincinnati, OH.
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Heavens, J. W. (1997). "The Trenchless Renovation of Potable Water Pipelines."
Proceedings of the Annual Conference of the American Water Works Association,
Atlanta, GA.
Jeyapalan, J. K. (1999). "Personal Communication on Unit Costs for Fold and Form
Pipe." Pipeline Engineering Consultants, CT.
Morris, J. (1996). "Cost Effective Management of Water Pipelines and Networks."
Presented at Water Pipelines and Networks, London, England.
Spero, M. I. (1999). "Trenchless 101 - For Industrial Applications." Proceedings of the
Underground Construction Technology, International Conference and Exhibition,
Houston, TX.
Trenchless Technology Center (TTC). (1994). "Long-Term Structural Behavior of
Pipeline Rehabilitation Systems." TTC Technical Report #302.
U.S. EPA. (1997). Drinking Water Infrastructure Needs Survey - First Report to
Congress. EPA/812/R-97/001. Office of Water, Washington, DC.
Watson, C. (1998). "Rehabilitation of Potable Water Mains - The Changing Policy of
Northumbrian Water." Proceedings of the International Conference on Rehabilitation
Technology for the Water Industry, Lille, France.
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Table 1. Summary of Rehabilitation/Replacement Methods
Method
Cement Mortar Lining
Epoxy Lining*
Sliplining
Cured-in-Place Pipe (CIPP)
Fold and Form Pipe
Close-Fit Pipe
Pipe Bursting
Microtunneling
Horizontal Directional Drilling
Pipe Size Range** Common Materials
(diameter in inches)
4-
4-
4-
6-
8-
2-
4-
12
2-
60
12
108
54
18
42
36
-144
60
cement-sand
epoxy resin
HOPE, PVC, fiberglass
reinforced polyester
polyester resins
HOPE, PVC
PE, PVC
HOPE, PVC, ductile iron
HOPE, PVC, concrete,
steel, fiberglass
HOPE, PVC, steel, copper,
ductile and cast iron
Generic Cost References for Cost
($/inch
diameter/foot)
1 -3
9-15
4-6
6-14
6
4-6
7-9
17-24
10-25
Gumerman et al. 1992
Conroy etal. 1995
Gumerman et al. 1992
Gumerman et al. 1992
Jeyapalan 1999
Arthurs 1999
Boyce and Bried 1998
Boyce and Bried 1998
Boyce and Bried 1998
Note: * Cost is in $/foot
** To covert from inches to centimeters, multiply by 2.54
HDPE - High Density Polyethylene; PVC - Polyvinyl Chloride; PE - Polyethylene
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