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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