Replacing old galvanized water supply line from meter to entry at house

[k9mlxj]

You should be able to "push" the new pipe under the concrete slab, but WILL need to make a big enough hole to "bend it" up out of the ground.

The Water Company tecnhician said 18 inches down would be the right depth.

I am now leaning on doing this myself--or get some young kids to do the digging. Just need to know which way to dig (particularly under the concrete slab).


So some details want to know... :


1. I wonder how big of a hole size (rough diameter) do I need to dig to push the new pipe under concrete slab? (It's 7 ft into the concrete slab before the current pipe turns upward)


The old pipe is in the way -- so need to pull it out first?

If so, still need to break/cut out a hole around the concrete slab and cut the old galvanized pipe,

then, do the digging from the dirt end on the concrete slab, toward the bottom of the spot where it comes up above concrete, and then pull out the old galvanized pipe section after the hole is made?


2. Since 18 inches down would be the right depth, and the water meter is about 1 feet below ground right now, so he said that the pipe would slope downward.


Just wonder about this detail -- at which point would the new pipe slope downward after the water meter --

-- immediately after new pipe connects to the water meter, or
-- a few feet further -- before going under the side walk (it's about 6 feet after the meter before the new line would go under a side walk)
-- immediately after the side walk
-- immediately before enter the fence of the backyard?
-- immediately after entering the fence of the backyard?


3. The water company technician suggested the new line normally goes diagonally to the concrete slab (for a shorter length?).


So wonder if the new line should go diagonally

- immediately after the meter, or
- after the fence in the backyard


Haven't done this before at all, so wonder about these details... .


[ Meter ] - (6 ft dirt) --> [ side-walk ] (4.5 ft wide) --> dirt (5 ft) --> fence --> 30 ft dirt --> concrete slab (7ft) --> goes up to concrete level


Thx.

[k9mlxj]

The Water Company tecnhician said 18 inches down would be the right depth.

1. I wonder how big of a hole size (rough diameter) do I need to dig to push the new pipe under concrete slab? (It's 7 ft into the concrete slab before the current pipe turns upward)

The old pipe is in the way -- so need to pull it out first?

Been a while as I had some other things to work on.


Coming back to this, anyone would have tips on the hole size on the concrete slab to be made (like 24" x 24" is big enough hole?) where the copper pipe comes up from 18 inches down?


Also, I happened to talk to a HD guy and he said I could use hard copper pipes underground as they are stronger than the soft copper pipes.

I guess hard copper pipe isn't recommended for earthquake-prone area so it's a no-go?

[k9mlxj]

no one?

Also, if I were to use soft copper tubing (1" I suppose), is it better to bend 2x45 degrees instead of 2x90 degrees when I need to bend it to go down 20"?

Wonder the simplest way to bend the 1" soft copper tube w/o kinks or flattening the tube (conduit bender won't work?).

[Terry]

Soft copper comes in a round coil. If you need a bend, you can just use the rounded section and cut it out. Copper warms up and stiffens as it's bent. You only get one shot when you are unrolling the copper.
No fittings under a slab unless they are silver soldered. Soldering with lead free or 95 percent tin doesn't count as silver solder.

You tunnel under the slab or bore a hole under. If you plan on digging from inside, consider what size your shovel is.

With the price of copper, it starts to make more sense to think about things like Poly or PVC.
Anything you put in there is going to be a huge improvement.

Water pipe sizing

[big2bird]

I live just south in Anaheim. I replaced mine almost 25 years ago, and used 1" PVC 18" down. 20' is under the driveway, and I still have had zero issues. I dug a trench, used a female adapter, and drilled under the driveway with the new pipe, and left it there.
If you saw cut the concrete, I would put it in an 4" ABS sleeve, so you can change/add pipes.

[k9mlxj]

I replaced mine almost 25 years ago, and used 1" PVC 18" down. 20' is under the driveway...

Here's something I don't understand. I checked my water bill and it states "Rate Code /Service Size : RES_T_B 3/4 inch".

But the connecting old galvanized pipe (from the house) size to the meter is 1" diam. When it comes out of the concrete it's reduced to 3/4" when connecting to the copper pipe from the house.




I called the water company and the lady just followed my account profile and said I needed a 3/4" pipe connecting to the meter.

But I wonder about the reason the Service Size states 3/4" when the galvanized connecting service pipe size is 1"?

I would put it in an 4" ABS sleeve, so you can change/add pipes.

An ABS sleeve -- for the whole length of the service line from the meter to above the concrete by the house?

[Terry]

If you have a two or three bath home, you should have a 1" service to the home with your 3/4" meter.
Only if you have a one bath home would a 3/4" service make any kind of sense.
The larger pipe size reduces friction at very little cost on the upgrade, which is noticeable to the homeowner when the plumbing fixtures are used. It's better to oversize a service then to undersize it. If you have two baths, then 1" is the correct size.

[k9mlxj]

What does the 3/4" service size on the meter mean then?

[Terry]

Water pipe sizing

Have you looked at this page yet?
It has a chart from the code book explaining pipe size. We don't have to reinvent anything, this stuff is old news.
Water meters used to be 5/8", and then in the last few decades, or maybe I should say, in the last 60 years they were 3/4".
You can pass a lot of water through a 3/4" meter and setter.
After that, you need to worry about friction loss. The longer the tubing is, the more loss you have. Think drinking a pineapple shake through a coffee stirrer.
We also can't use even 1/2" PEX for a tub spout with diverter. It's so small it pushes water upward to the shower head in the "tub" position.

Friction loss determines pipe sizing. The longer the pipe, the less water that can go through it.

Copper Pipe at 80 feet with a 3/4" meter and setter.
1/2" pipe, 6 units
3/4" pipe, 19 units
1.0" pipe, 36 units

A bathroom with a tub, toilet and lav is 7.5 units
The cold requires 3/4".

[jadnashua]

Over a short distance, when you reduce the pipe size, the water just speeds up through that short section and slows back down again when the pipe gets bigger, maintaining the volume. It becomes a big issue when the restriction is long, then it cannot recover, or the velocity gets higher than you want and can erode the piping.