Water service lines are the pipes that lead from the water main to the customer’s plumbing.  The service line consists of all pipe, valves and fittings between the control box (curb box), through the meter and ending at the customer’s plumbing.  These 15 questions and answers provide a basic overview of maintenance on water service lines in the distribution system. 

Distribution system maintenance includes routine sampling, inspection, leak repairs, maintaining carrying capacity, pipeline cleaning, lining mains in place, main-break repair and thawing of frozen pipelines.  These questions and answers are from the book Introduction to Water Distribution, Principles and Practices of Water Supply Operations, Volume 3, AWWA, Denver, Colorado, 1986, ISBN 0-89867-188-4.

Question 1:  What is the purpose of a water service line?
Answer:  Service lines transmit water from the distribution main to residential, industrial and commercial users.

Question 2:  Is a permit needed to install a water service line?
Answer:  A plumbing construction permit will be required from the Division of Plumbing, phone 502-573-0364.  Also, for potable water lines, contact the Division of Water regarding drinking water construction permits, phone 502-564-3410. 

Question 3:  What is the function of a gooseneck in a service line?
Answer:  A gooseneck is a flexible connection that provides for ease of installation and allows for any settlement of the overlying material or expansion and contraction of the service line because of temperature variations.

Question 4:  What is the function of a curb stop?
Answer:  A curb stop is a shutoff valve that enables water systems to regulate (turn on or off) water flow in the service line before the line enters the customer’s property. 

Question 5:  What is the purpose of standardizing water service lines?
Answer:  Standardization helps simplify ordering materials and maintaining inventories, enables suppliers to take advantage of economic bulk ordering and saves time and money in not having to train field crews on a variety of installation techniques.

Question 6:  What factors should a water supplier consider when selecting service line materials?
Answer:  Factors to consider are cost, durability, American Water Works Association standards, ease of locating and standardization.

Question 7:  Explain why lead and wrought iron are not used on residential service lines.
Answer:  Lead joints are difficult to install properly and there is some question concerning the safety, in terms of water quality, of lead service lines.  Wrought iron is rigid and requires threading, making it difficult to install, and is subject to corrosion.

Question 8:  What is a possible problem when iron services are installed with bronze curb stops?
Answer:  Use of dissimilar materials often forms a galvanic cell and causes corrosion of the pipe.

Question 9:  Explain the difference between a wet and dry tap.
Answer:  A wet tap refers to the water main under pressure, while a dry tap is made when the main is empty.

Question 10:  What are two controlling factors in determining service line sizes?
Answer:  Pressure losses and flow velocities through the pipe.

Question 11:  What two factors determine the depth and location of a service line?
Answer:  Frost penetration (freezing) and location of other utility lines, particularly sanitary sewer and storm sewer.

Question 12:  In Kentucky, what minimum depth should water lines be buried to protect against freezing?
Answer:  The plumbing code and standard regulations for potable water supply and distribution, 815 KAR 20:120, Section 13, state, “A water service shall be installed at least thirty (30) inches in depth.”  Contact Division of Plumbing, phone 502-573-0364.

Question 13:  What hazards are associated with electrically thawing a frozen service line?
Answer:  (1) Damage to the service line, plumbing and electrical appliances.  (2)  Stray current can cause fire or electrical shock.

Question 14:  Cite and review any state or local regulations on separation distances of water main and sanitary sewer.
Answer:  State regulations refer to “Recommended Standards for Water Works,” (a.k.a. Ten State Standards), which is incorporated by reference into Kentucky regulations for water supply, 401 KAR Chapter 8.  To obtain a copy, contact Health Education Services (HES), phone 518-439-7286 and ask for “Recommended Standards for Water Works,” 1997, Great Lakes Upper Mississippi River Board of State and Provincial Public Health and Environmental Managers, Albany, New York.  A quick summary is to maintain a minimum 10-foot horizontal separation between water mains and sanitary sewer with an 18-inch vertical separation at crossings.  Additional local regulations may apply.

Question 15:  What items should be recorded on a service connection record card?
Answer:  Permanent service number, applicant’s name and address, dates of application and installation, sizes of corporation and curb stop used, size and type pipe used, depth of installation and detailed measurements of location.