upgrading water service

I live in new jersey, and they go by the national plumbing code. I just started a small addition adding a bathroom and a bedroom. I have a standard single family home with kitchen, 2 full baths, and laundry room. The inspector says that because I'm adding the new bathroom I must upgrade my main water supply line to 1". I currently have a 3/4" line going into a 1" meter and have a 1" branch line supply my cold water lines. Is this nessasary to dig up my 3/4l and replace it 1". Does anyone know the requiements when doing addition work on a home and when the inspector can require you to upgrade your older service. I thought that the exsiting part of the house was excluded from the new code requirements. Please someone help. They want 6000 to replace it and the bathroom plumbing was only 2000.

My guess is you are adding enough fixtures to bump up the pipe requirements. On the home page of this forum you can find a link to a chart that will list all of the information you need to determine the pipe size required for your home.

pipe

That is a common problem when you add to the plumbing system, and it is not "grandfathered" in just because it is already there. In some cases the main sewer line has to be increased in size also.