Can You Upgrade a Domestic Water Line for New Sprinkler Main?
April 22, 2019

It is often that our customers will inquire about using their existing domestic water main when being required to have a new sprinkler main installed for the building. First and foremost you are required to have a DEP-approved cross connection letter as well as an approved DOB plan; without these two items, there is no possibility of using the existing water line.

Example of Cross Connection
Example of Cross Connection

DOB approved plansfor water main
Sample DOB approval

If you have the required approvals, it is now vital to cross reference the details included on each of the plans, with the existing water main. If the existing water main is the same size as the size of the water main on the approved plans, you may be in luck.

You would most likely be required to increase the size of the existing tap connection on the city main due to DEP code requirements. You would also be required to install a curb valve within 2′ of the curb line and install an OSY valve as your main control valve inside the building.

Tap or wet connection
Tap or wet connection

Curb valve below ground
Curb valve

Next, you must consider the age of the existing water main and the cost-benefit of adding the tap connection and curb valve alone. If your water main is more than 10 years old you may want to spend a few thousand dollars to have the entire water main replaced along with the new valves. The last thing you would want to experience is installing the new valves only to find out that the old pipe has sprung a leak shortly after the valves were installed.

You should also consider the overall cost of installing the valves on the existing water main if the licensed plumber is required to come back at a later date for the DEP inspection. In this case, you are going to incur the cost for the plumber to re-mobilize a crew, trucks, backhoe, etc.