how deep is your waterline?

[Obed]

Our waterline is 2 ft. deep. We are in Tennessee with a 12" to 18" frost line.

Regarding the diameter of your water line, having a larger dia. pipe than the 3/4" at the filter will make a difference if your waterline is long. Smaller diameter pipes will have a significantly higher coefficient of friction than larger pipes. The result can be lower water pressure for smaller pipes when you are running water. Yes, a 1 1/2" or 2" dia. pipe will give you better water pressure than a 1" pipe on a long run, even if the pipe at the water filter is only 3/4". I was a nuclear power and steam plant engineer in my former life so I know a little bit about fluid flow.

That being said, we ran a 1" water line 250 ft. to our garden and without water pressure issues. If I were running a 700 ft. long waterline, I might consider making the pipe a little bigger. My dad has a 500'water line running from the city water line to his house on basically level ground; his water pressure is not great. I think his waterline is 3/4".

I'm sure you will enjoy the new waterline. I'm amazed the original line was only 3" deep.

Obed

 

[RFB]

The 3/4 inch filter is an inconsequential restriction in contrast to the friction loss incurred by 700 feet of hose/pipe.

The member who suggested larger diameter is correct.

 

[CurlyDave]

For PVC pipe there are considerations other than pressure drop.

Microscopic particulates in the water supply will cause pipe erosion at velocities greater than about 7 feet/second. This is usually the controlling factor when sizing long runs of water supply pipe.

Essentially, make it too small, and it will actually wear out. You probably don't want to dig it up and replace with larger pipe in a few years.

In Florida, I would also check pressure rating vs. temp. With PVC pipe it drops pretty dramatically. For instance, see this chart:PVC Pipe | Standard & Custom Extrusions | Schedule 40 & 80 Temperature Derating

 

[blueriver]

No codes here either ... when I bought this place I had no idea where things where buried. Over the years I have found them ... some I hit driving T post in the ground ... at about 6" others I uncovered when plowing the garden.

I do like the caution tape idea and I also agree for your run to use larger diameter pipe.