Water Pipe

Water pipe materials today come in many different sizes and types. There is poly vinyl chloride (PVC), ductile iron pipe (DIP), steel, galvanized, copper, and high pressure, or heavy duty, high density poly ethylene (HDPE) water pipe materials. These water pipes are designed by engineers to withstand high pressures from water inside the pipe, as well as compression from soil burying the pipe on the outside.

Modern day water pipeline systems have water pumped through water pipelines to get to the ultimate end user. This pumping causes pressure to build up in the water pipes. Water pipes are designed with different tensile strengths and thicknesses, along with other properties, to accommodate different pressure zones and higher pressures. All water fittings and various parts also must be designed to correspond with the pipes maximum pressure rating.


There are tens of thousands of water parts, or fittings used to install the various types of waterline materials of today. This does not take into account all the variations of water pipe in our history, such as redwood water mains and asbestos concrete pipe (ACP). The specifications for water parts, material types, and various manufacturers, vary from Agency to Agency, and Owner to Owner. All water systems are designed to carry a predetermined amount of pressure in a zone. The Agency will then specify the pipe, material type, pressure rating, and manufacturer required for that zone. This is different than the requirements for the private property owner.

Water pipelines on private property for domestic use are normally rated for less pressure than pipelines designed for public water, or fire mains. The private property owner is normally governed by local building or plumbing codes. To separate higher pressure rated pipes that Public Agencies use and lower pressure rated pipes that private property owners use, contractors must install a Pressure Reducing Valve (PRV) prior to using lower pressure rated pipe. The PRV reduces pressure at the device, essentially creating a high pressure zone on one side and a low pressure zone on the other. This allows normal use of domestic water in your home or office building without pipes bursting within walls.

Even though property owners may come across the same type of materials on their property or within their building walls that are out in the city street, such as PVC and Copper, remember that water pipe materials are made with different properties that can
cause them to withstand different pressures. Additionally, joint materials and fittings are also different, and are subject to the same difference in pressure ratings. So no matter what type of water pipe is being installed, contractors must verify that they are using correct rated pipe to match pressure zones for that pipe being installed.