A Deep Dive Into Corporation Stops

A Deep Dive Into Corporation Stops

A Deep Dive Into Corporation Stops

The water service lateral is the city’s way of bringing water access to buildings or homes. In fact, it takes a lot of parts to successfully get this resource to travel all the way from point A to its destination. The corporation (corp) stop is an important part of the water service lateral and is considered the initial control valve of the service line.

The sole purpose of a corporation stop is to allow for the installation of a new water service line without interrupting the water main pressure. As a special stop valve that is installed into the water main, the corporation stop is usually used only once. However, it may be utilized again in the instance that water needs to be shut off deep below the ground for one reason or another.


The corporation stop connects to the service line and water main through the use of threads. Below are common thread options for the inlet and outlet of the valve:

Inlet (Faces Water Main)

Outlet (Faces Service Line)

  • AWWA/CC (American Water Works Association/Corporation Cock)
  • MNPT (Male National Pipe Thread)
  • Flare
  • MNPT (Male National Pipe Thread)
  • FNTP (Female National Pipe Thread)
  • Compression – CTS (Copper Tube Size), PEP (Polyethylene Pipe), PVC (Polyvinyl Chloride)


Corporation stops can be a ball or plug valve style. Both have a 360-degree operating head, but the ball was designed for low turning torques and operating pressures up to 300 PSI. The plug valve is 100 PSI on 1/2”, 3/4”, and 1”, along with 80 PSI on 1 1/4”, 1 1/2”, and 2”. 


A.Y. McDonald corporation stops come with multiple options in order to cater to as many applications as possible. See below on some of our most common product features we offer:

  • Removable tee head for easier on/off operation. The tee head can be removed to allow the corporation stop to fit inside a tapping machine.
  • Non-removable tee head for easier on/off operation. This feature is only used with drilling machines as it won’t fit inside a tapping machine.
  • Di-electric bushing for helping prevent electrolysis and galvanic corrosion.


The inlet side of the corporation stop connects the valve to the water main. This is also referred to as ‘tapping’ into the water main. There are two common methods in which to tap into the water main, such as saddle tapping and direct tap.


Saddle tapping is the process of installing the service line to a water main by a corporation stop. The corporation stop is installed into a saddle that wraps around the pipe. When a pipe is saddle-tapped, equipment is attached to the corporation stop with a tapping adapter that permits a cutting tool to be fed through the stop to cut a hole in the pipe. During this process, the pipe wall is not threaded as the corporation stop is installed/”threaded” into the tapping saddle.



Direct tapping involves the tapping of threads into the pipe wall and the insertion of a corporation stop. Generally, a hole is drilled into the pipe when a direct tap is created, and the threads are cute while using the same bit. This process allows for the installation of a corporation stop. A tapping adapter is used to connect the tapping machine to the corporation stop.

The corporation stop is an essential part of the process of giving communities access to water. Too learn more about how this portion of the water service lateral works, contact A.Y. McDonald by calling 1-800-AY-CARES, taking the ‘Corporation Stops’ AYU course, or filling out a contact us form on aymcdonald.com.