When sizing a water main it is important to consult with a NYC Licensed Plumber who will closely follow the NYC DEP sizing table. The primary factors used by the sizing table are the number of plumbing fixtures in the house (toilets, kitchen sinks, washing machines, showers etc.), distance of the new service pipe from the city water main to the house, and the rate of flow (gallons per minute). Each of these factors will assist in determining the exact size of the water main, tap connection and ultimately guarantee sufficient water pressure throughout your house.
A general guide to follow for your water line:
The average single or 2 family home with 2-4 bathrooms and 2 kitchens, will most likely require a 1”-1 ¼” copper water line.
3 family homes will most likely require a 1 ½” copper water line
All sprinkler main or combined water main sizing will be determined by a NYC certified engineer.
Note- there are additional variables a licensed plumber will consider, the above examples are a rough estimate.
When is it a good time to increase the size of your water line?
If you are repairing your water line due to a leak, upgrading from lead to copper or if you are adding additional plumbing fixtures to your home, it may be an ideal time to increase the size of the existing pipe. It is common that the old water main will be replaced with the same size pipe however; this may not be the best decision for your home. In many cases, replacing the existing water line with the same size pipe may actually be illegal if it no longer falls within the NYC plumbing code. Increasing the size of the pipe from a 1” to a 1 ½” water line may only be an additional $200-$500 pending the length of pipe being replaced; it will allow for much greater water pressure and will avoid any potential violations if the current line does not fall within the updated plumbing code. It is also important to make sure that the tap connection falls within in the plumbing code or this may have to be replaced as well. The fee for a new tap connection is $300 when having it installed at the same time as the water line.
What size tap is required for your water line?
If you are installing a new domestic water line smaller than 3”, NYC plumbing code reads that the tap must be one size smaller than the size of the pipe. EX. 1” pipe requires a ¾” tap. This rule may be subject to change if you are replacing an existing water main. EX: If you are installing a 1 ¼” water main you can connect to the existing ¾” tap.
If you are installing a new domestic water line smaller than 3”, NYC plumbing code reads that the tap must be one size smaller than the size of the pipe. EX. 1” pipe requires a ¾” tap. This rule may be subject to change if you are replacing an existing water main. Ex. If you are installing a 1 ¼” water main you can connect to the existing ¾” tap. If you are installing a domestic water line 3” or greater, the wet connection must be of the same size as the pipe unless you are replacing an existing 2.5”water service where you may connect to a 2” tap. EX: If you are replacing an existing 2.5” water main that is currently connected to the city main with a 2” tap, you can connect your new 3” ductile iron water main to the existing 2” tap. Any domestic water service larger than 3” must be connected to the city main with a wet connection of the same size, even if you are replacing an existing service. A new fire sprinkler service must be connected to a wet tap or wet connection of the same size. If you are replacing an existing 2.5” pipe that is currently connected to the city main with a 2” tap, you can install a new 3” service using the existing 2” tap.
The Harris family has been in the plumbing business since the early 1900’s, we have experienced all types of water main and sewer jobs. There is no job too big or too small for us. We are there for you in an emergency if you suffer a failure of water main or sewer service, our friendly and knowledgeable staff is ready to dispatch one of our fully stocked service trucks 24 hours per day, 7 days per week.