When you install the supply lines, begin at the service main and work into the house and up to the fixtures. The initial connection with the municipal water main is almost always supervised directly by the local authorities. It must be made by workers from the municipal department or under that department's inspection. In an increasing number of cities, water authorities insist that corporation and curb cocks be supplied by them to insure the quality and standardization of these fittings. This is proving more and more necessary to safeguard municipal supplies.
Corporation and curb cocks
The actual connection to the water main is made with a corporation cock. Usually made of brass, it is the fitting placed by local authority. It acts as a control stop which permits the water to be turned off should the building become unoccupied. However, since it is buried at the depth of the municipal main, a hole has to be dug before the corporation cock can be used.
Many localities insist that a curb cock be inserted at some point outside a building. Even if it is not required, a curb cock is recommended since it provides a means of turning off the house water. This is particularly useful in houses periodically left vacant during freezing weather. The cock should rest on a brick, stone, or cement platform to prevent its being forced into the ground by any weight pressing down on it from above.
Somewhere along the line of pipe carrying water into a building, there should be some provision for expansion and contraction resulting from changes in the temperature. With lead or copper tubing this can be done easily by providing a bend or "gooseneck" in the pipe. This will also compensate for any variations in length caused by settlement, expansion, or contraction. In iron piping, an extra U-shaped section may be needed, according to local climatic conditions.
The house main should be laid far enough below the freezing line to provide reasonable assurance that the pipe will not be subject to continual freezing. Iron pipe may burst after its first or second freezing, and copper tubing after its sixth or seventh freezing.
You should also avoid placing pipe in soil containing a large proportion of cinders. The sulphur compounds contained in cinders will be washed out by rain and will corrode underground piping, especially copper. Try to keep main runs as level as possible and protect them by using shorings or platforms.
A metal sleeve or a wrapping should be installed to protect the portion of the pipe which extends through the house wall. A sleeve of cast iron is preferred. It should be slightly larger than the pipe it protects in order to allow for expansion. The sleeve prevents chemical compounds in the concrete from attacking and corroding the main.