Need expert help, please! 1920 plumbing

Dear experts, I bought a "fixer upper house" built in Memphis in 1920.
All the original water supply plumbing is/was lead from the street meter to each fixture/ The inner diameter of this lead pipe was a little less than 1/2 inch.

Over the years, some people had added assorted copper and pvc here and there under the kitchen. several joints were leaky and the water heater was nasty, so I decided to redo it all since the crawl space is large and easy to work in.

I soldered 1/2 copper to the lead supply line coming out of the dirt, and ran 1/2 copper to everywhere else under the house. It all looks good but the water pressure didn't improve. I have now dug up the main supply line all the way to the street. That's the only original lead pipe still in use.

What size new line should I use there to make things right and improve the pressure?

I would like to leave the 1/2 branch work under the house if I can, but I would like you all to tell how to make it right, whatever that involves. I'm handy and learn fast, but this is my 1st plumbing project other than installing water heaters! Please help!

I'm not a plumber but........I would replace all of the lead pipe and put in a minimum 3/4" copper from the meter to the house.

You need to know distances, number and type of fixtures, incoming pressure and then run the numbers through the supply pipe sizing charts in your code book.

A lot of old houses had 1/2" water supply lines, but that won't cut it with today's codes or usage. Depending on how many fixtures you have, it might have been better to use larger pipe in the house, too.

You can buy an inexpensive water pressure gauge that screws onto a hose bib. You may want to check your static pressure., then with water running.

Thanks for the advice so far. Several people I've talked to have said to use 3/4 copper. The house has 1 original bath, an ordinary kitchen with added dishwasher, and two hose bibs. The existing line FROM the meter is the same small lead line as those that were under the house.

Thanks!! Don

You should also know that PVC is usually not legal to use indoors. You can use it to bring water from the street to the house (underground) and for underground irrigation.

Gary- Really? I believe you- it's interesting because of all the myriad of pvc that someone had added. My house had a half-ass added on bath where a rear porch had been. All the plumbing to it was pvc. (at least 4 different sizes too) However, the sink, toilet, and shower were disconnected for some reason and since the floor joists were rotted and sagging, I gutted the whole thing and made it a big closet for now.

Some day I will probably make it a nice bath.

How about the use of copper 3/4 line from the street? IF I run a hose bib directly off that line, should I keep 3/4 up to the spigot or reduce the line to 1/2?

Thanks!

It seems like this question get's asked about 10 times a week. There is no way to give a definitive answer to your question without knowing all the variables. I.E. incoming pressure. Distance to fixtures, Type and size of water heater, Type of pipe you are using, number of fixtures and their designed flow rate. I know that ain't what you want to hear. You want someone to say yes, 3/4" would be fine. But the calculations must be done to properly size the lines. Furthermore, these calculations require using the proper charts and a couple hours of time to figure. I can't speak for everyone else here, but I doubt anyone is going to provide that service for free.

Thank you! project working so far.

Thank you all for your advice. I dug up the old lead line from the street and replaced it with 3/4 copper. I put a T in the line up next to the house and ran a hose bib in one of those (mostly) buried plastic boxes. The soldered joints have shown no leaks after 2 days and the water pressure at the new hose bib is great! So I'm reburying it all. Soldering down in a 2 ft deep trench was awkward, but far from impossible. The digging (all by hand with an ordinary shovel) was the worst part but Memphis has no natural bedrock--it's all clay and not too bad if it has rained recently.

**To NHMASTER: Your point above is very well taken. I kinda launched into this on an impulse last week. So far, I'm happy with the results.