Water Main Ball Valves and How They Function

If you have had a water main  2″ or smaller installed over the prior five years, there is a good chance that a full port ball valve was included in the installation. The valve controls the water from the external water line to the inside of your house.  Previous to ball valves, gate valves were commonly installed with new water mains but have been proven to be less dependable than ball valves.  Gate valves become difficult to turn after not being used for extended periods of time.  They also function with a stem that lowers inside the valve which increases the chance of getting stuck in a halfway closed position, potentially decreasing the amount of water pressure in the building.  A ball valve is full flow, the valve is open when the handle is aligned with the pipe and closed when the handle is turned ¼ clockwise forming a right angle to the pipe.

label_GOOD_Brass_Gate_Valves_Non_Tested

It is very important to open the ball valve at a slow pace to avoid any damage to the existing piping. If the valve is opened too quickly, the pipe may suffer from a pressure surge creating leaks, a pipe collapse, heavy vibrations or a loud noise.  If you decide to turn-off the water using the ball valve, it is important for the pipes to drain by unscrewing the sinks aerator (small screens) on the end of the faucets before the water is turned back on.  Removing the aerators will avoid clogging from any small particles that may have loosened on the inside of the pipe.


What to do if a gate valve or ball valve has broken in the closed position?

If your main water line control valve is stuck in a closed position you should first try to locate a curb valve on the outside of your home.  Pending the age of your water line, the curb valve may be located 2’ of the foundation wall or 2’ of the curb line near the roadway.  If the curb valve is still functional, the inside valve can be changed quickly with no major cost associated with the repair.  If there is no curb valve or if the existing valve is non-functional, you will have to contact a licensed plumber to close the water at the tap connection in the roadway.  Closing the tap connection requires obtaining permits with DOT, excavating and restoring the roadway which will be more expensive than closing the curb valve.

It is important not to apply additional pressure to a valve in the event that it is not opening/closing, this may result in additional damage and a complete loss of water in the building.  You may want to slowly turn the valve back and forth which may result in the valve releasing from the stuck position.  If the valve does not open/close it is highly advised to call a professional to assist in the next step.


Harris Water Main & Sewer Contractors Inc. is the only 4th generation family owned and operated water main and Sewer Company serving Brooklyn, Queens, Manhattan and the Bronx.  The Harris family has been in the plumbing business since the early 1900s. You can contact us 24 hours a day, 7 days a week to answer questions or discuss concerns regarding your job @ 718-495-3600.