House supply size increase

[cadillacben]

I'm probably 200' off the road and I ran a 3/4" supply pipe originally with a 3/4" tap off the city water pipe. Problem is that my water pressure sucks by the time it reaches the house. Knowing what I know now about hydraulics, I'm thinking that the 3/4" pipe has too much resistance and a larger pipe should help that out. My question is what size should I go to, 1" or 1 1/4".

I have:
2 - hose bibs
4 - faucets
2 - toliets
2 - showers

Thank you for any help

[pushkins]

3/4" pipe with minimal pressure will carry 660 GPH
1 1/4" pipe with minimal pressure will carry 1500 GPH

City water isn't under significant pressure so the above would be pretty close.
What you will probably have to do is start out with 1 1/4" and reduce down along the way to probably 3/4" nearer the house.

I'm not sure if you would need to start with 1 1/4" maybe an 1" would do the job, wait for others to post.

[suemarkp]

I have a similar problem -- a 100' run of 3/4" copper and it is up hill which further steals pressure. First thing to do is get a pressure gauge with a garden hose connector. Put this on a hose bib and measure the pressure (hose turned on, and no water being used in the house), preferably from a hose bib on a pipe run as close as possible to where the water enters the house. This is your static pressure and needs to be 40 to 60 PSI or higher (over 75 PSI is too much, and 55-60 is perfect). If this is too low, pipe isn't going to matter and you need to get your water company to incease the pressure (or install a booster pump yourself).

Now, turn on some water devices that you'll use at the same time -- e.g. shower, a lawn sprinkler, sink, flush a toilet, and run out to read the gauge. How much has the pressure fallen? This is the pressure drop due to the dynamic pipe loss. I would expect at least a 12 to 15 PSI drop in that long run of 3/4" pipe. Increasing the pipe diameter will reduce that pressure drop. I'm just guessing here, but I think a 1" pipe will cut the drop in half, and a 1.25" pipe will cut it by a factor of 4.

It is possible you have a restriction somewhere, and it could be in the house (e.g. main shutoff, solder blob inside a pipe, old galvanized pipes, bent pipe in feed to house, etc). So if you have a major loss in pressure, replacing the pipe to the house may not fix all of it if there is some other problem. If you're going to go to all the effort to dig a trench and run a pipe, I'd run 1.25" 200 PSI polyetheleyne pipe.