Sizing for natural gas line

Old 07-22-19, 08:37 AM
Thread Starter
Join Date: May 2019
Location: United States
Posts: 8
Received 1 Vote on 1 Post
Sizing for natural gas line

Changing from propane to natural gas and due to the tank location and access to the the line running into the house, the gas company wants to come down on the other side (right) of the house. The kitchen is located on the right side and there is flexible 1/2" line to the gas cook stove. The 2 estimates received said they cannot tie into that line as the main supply to the water heater and the furnace are on the other side of the house. The gas company says they can tie into the 1/2" flexible line. They want $250 to rub the line about 10'. The estimates are approx. $1000 to run the new line.which is about 50'. The line would run under the house which is very accessible as you can stand under the house so work area is good.
Looking for input as what the gas company says is doable and to code.
Old 07-22-19, 05:33 PM
Join Date: Jun 2012
Location: USA
Posts: 1,714
Received 59 Votes on 52 Posts
Need to know specifics but in general a furnace and water heater would be too much for 50' of 1/2" pipe. Tapping a gas stove on the same 1/2" would be even worse.
Old 07-22-19, 10:54 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 62,729
Received 1,618 Votes on 1,490 Posts
Welcome to the forums.

I've never heard of a gas company running piping for a customer. Typically the just supply to the meter. Gas piping usually requires an inspection. So it would be doubtful they would not do it correctly.

In order to determine the size of the pipe needed...... you'd add up the kbtu's needed by the furnace and the water heater. A typical furnace is around 100kbtu's and a water heater is around 35kbtu's. Based on +50' that would mean a 1" gas line.
Old 07-23-19, 04:59 PM
Join Date: Oct 2008
Location: USA
Posts: 3,022
Received 13 Votes on 13 Posts
For the service line to your meter, the gas company calls the shots. For piping inside your house, after the meter, you are often on your own, subject to local inspectors and codes. My advice is to comply with whatever the gas company says.
Old 07-24-19, 12:15 PM
maarkr's Avatar
Join Date: Mar 2014
Location: United States
Posts: 444
Received 13 Votes on 11 Posts
i calculated a 1" pipe for my 50' house run down the center, with feeds coming off of it for water heater, heater, dryer, grill, stove, fireplace. My plumber installer put in 1 1/4" pipe and said I will never need to change the main pipe and will never have gas pressure drop issues, unless of course I install all kinds of new big gas items.
Old 07-25-19, 01:16 PM
airman.1994's Avatar
Join Date: Dec 2005
Location: VA
Posts: 5,795
Received 8 Votes on 8 Posts
you need to know how much pressure before you can size.
Old 07-29-19, 05:44 AM
Thread Starter
Join Date: May 2019
Location: United States
Posts: 8
Received 1 Vote on 1 Post
Thanks for all the replies. They now seem to agree that the 1/2" line is not sufficient. Having a few more contractors provide quotes.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: