Irrigation Helps & Tutorials - How to replace your water supply line

How to replace your water supply line

In most places you are required to obtain a permit to replace the water supply pipe or even to simply do anything to it. Contact the city for details

As a reminder: the exact water supply you will be working on carries the water that you and your family use and consume everyday. Be careful not to get any dirt into the pipes when working. Once you complete the project, make sure you turn on all of your water faucets for several minutes in order to flush out all debris.

Water Mains, Goosenecks (service line), and Corporation Stops

The diagram below explains your water supply and where it is located. The water company supplies the water main line (A), the service line (B), and the corporation stop (C) where the shut off valve is located. You, as the owner, are responsible for the supply pipe (D). The idea is that the corporation stop marks the boundary between you and the water supplier.

Should you add a second pipe or replace the original?

If your water meter is installed right next to the corporation stop, or you do not have a water meter:

You can tap into the existing water supply pipe right after the water meter. Then install a new larger size pipe. The pipe leading to the sprinkler system would be the "new" supply line, using the revised gpm from the table below. The existing line and flow to the house would remain unchanged. Only the sprinkler system would be affected.

OR you can tap into the existing supply pipe rigth after the corporation stop/water meter and install a new second pipe to the house parallel to it. About a foot out from the house, connect the new pipe back into the old, smaller pipe leading into the house. This creates two supply pipes side-by-side to the house, with water flowing through both. This method can sometimes create problems, therefore, it is not recommended by most professionals.
OR remove the existing water supply pipe between the corporation stop/water meter and the house and replace it completely with a new, larger pipe. About a foot out from the house connect the new pipe to the old, smaller pipe leading to the house like the method above. This is the most commom method used.

Water Meter Size	New Replacement Pipe Size	Maximum Available GPM when a new supply pipe is installed
Water Meter Size	New Replacement Pipe Size	Using new SCH 40 PVC supply pipe	Using new PE (SDR-7) supply pipe*	Using new Type L copper supply pipe	Using new PEX supply pipe
5/8"	1"	15 GPM	15 GPM	15 GPM	15 GPM
3/4"	1"	17 GPM	17 GPM	17 GPM	17 GPM
3/4"	1 1/4"	20 GPM	20 GPM	20 GPM	-
1"	1 1/4"	33 GPM	32 GPM	27 GPM	-