Upgrading to 1 1/4" Main Line

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Jordan Duff

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We live on a 300' by 300' lot. We just had another baby, and are needing to add on. Once completed, we would have 3 toilets, 2 tubs, 1 walk-in shower, 1 tub/shower combo, 7 sinks, dishwasher, and washing machine. I also plan to add 2 bury hydrants, and 2 sillcocks. Some day we hope to add a garage with a full bath in it as well.

Since the addition will go over where the current main line is, I was thinking I should replace the old galvanized main line now. I thought I would put the portion that would be under the addition inside a PVC sleeve so it could easily be replaced if there were ever issues.

Because of the big demands from the exterior hydrants (probably would have multiples running at once) and the possibility of adding another bathroom later, I was thinking about using 1-1/4" Type A Pex for the main line (about 100'). I'd branch off of that with 3/4" Type A Pex (about 200' total) to each bury hydrant. I'd either continue the 1-1/4" into the house, or go down to 1" after the bury hydrants. If I have enough I'd rather do the 1-1/4" into the house since that will service the sillcocks, but there are a couple of possible issues. We'd like to add a patio some day to the area where the pipe goes into the house, so I may do a sleeve under that area, as well. If that's the case, I'd need to do a 90 degree turn, instead of coming in on a curve. Which would mean 100' of pipe may not quite be enough. I hope to do all of this work myself, but plan to have a plumber do the tie-ins at the water meter and the house.

If you've made it this far in my post, then thanks! These always turn out longer than I want them to...

Does my plan seem reasonable? Is 1-1/4" overkill? There is a big jump in price from 1" Type A to 1-1/4" Type A, but I don't want to be lacking pressure inside if the outside hydrants are running. On the hydrants - would they have plenty of water if I had one 3/4" line that tee'd off into two 3/4" lines after 50' or so, then went another 50'-75' to each hydrant after the tee? I'm not 100% sure how to do the lines for the sillcocks, but I can cross that bridge after I've got the main line tackled.
 

JG plumbing

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This depends on three things you don't have listed. Your pressure at the meter (minimum possible pressure as it will fluctuate a little throughout the day), how much pipe you have total, and the elevation change to the highest outlet from the meter.
 

arctic bill

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there is something else, a lot of municipal towns and cities ask for fire sprinkler systems on new or big renovation projects. so bear that i mind.
 

Jordan Duff

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The pressure at the meter is around 50 psi. There's around 100' of cold water lines already in the house (and slightly less hot water lines). Elevation change from the meter to the highest outlet is 20'.
 

JG plumbing

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What kinds of sinks? Lavatory vs kitchen vs laundry vs bar? How many?
 

JG plumbing

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1-1/4" should be fine. I'm cobbling this together figuring 300 ft of pipe total? You do need a 1-1/2" meter. Your pressure is on the low side.
 

Jordan Duff

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I’d go with 1.25” and not lose a bit of sleep.

have a great one👍
Am I ok with the bury hydrants sharing the same 3/4” line before they tee off into individual? Or should I come off the 1.25” with 1” and tee that into two 3/4”, one for each hydrant?
 

JG plumbing

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I would use the same 3/4 line. If you go off the main you could steal 12 gpm from your house. You close enough to the edge where you might see a difference of both are running. If you go off the same line you wouldn't be stealing as much from the house. You hydrants might see some noticeable drop this way, but it's better than the house.
 

Jordan Duff

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I would use the same 3/4 line. If you go off the main you could steal 12 gpm from your house. You close enough to the edge where you might see a difference of both are running. If you go off the same line you wouldn't be stealing as much from the house. You hydrants might see some noticeable drop this way, but it's better than the house.
That’s a good point. I guess I was hoping that if I went with 1.25” on the main line I would have plenty for both the hydrants and the house?
 

JG plumbing

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Your cutting it close. Your pretty high on the fixture count and low on pressure. Your right at the border of needing 2"pipe.
 

JG plumbing

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It could be that it works fine. Maybe you'll just want go off of the main for them, and know that you might have to throttle them?
 

frodo

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a 1 /4 line would be ok.
But because you say you will be adding at a later date
I would run 2- 1'' lines from the meter
add a plastic meter box. install 2 - 1'' valves
run 1 line to the house, run the other line to the outside faucets and the future garage addition
ask your water provider to give you a 1'' meter you most likely have a 5/8'' meter at this time

If your outside faucets will be under ground you will be required to have back flow protection on that line
 

Twowaxhack

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You need to calculate your expected demand. No one uses every fixture in the house at once plus the irrigation.
 

JG plumbing

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The tables don't account for every fixture running when comes to water. Drainage does.
 

Twowaxhack

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I’ve never found a house with a 2” water main.

And I’ve worked in mansions. 10,000 Sq ft + with 10+ baths on the property.
 

JG plumbing

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There's also the pex variable. 1-1/4"pex is actually more like 1"copper in size.
 

frodo

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I believe I said to run two 1'' lines. not a 2'' line
I believe I said to use one of the lines for the outside bibs and the future building.
the other line for the main house.
I HAVE seen 2'' lines run to houses. it all depends on how far the house is from the meter and useage.
I have run 2'' to houses. crashing through the woods on a ditch witch. Hell i remember standing in the seat dancing with ear buds on. tried to get the deer to bust a move but they just stared and shook their heads.
guess they did not like dazed and confused
 

Twowaxhack

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I believe I said to run two 1'' lines. not a 2'' line
I believe I said to use one of the lines for the outside bibs and the future building.
the other line for the main house.
I HAVE seen 2'' lines run to houses. it all depends on how far the house is from the meter and useage.
I have run 2'' to houses. crashing through the woods on a ditch witch. Hell i remember standing in the seat dancing with ear buds on. tried to get the deer to bust a move but they just stared and shook their heads.
guess they did not like dazed and confused
It wasn’t directed at you and distance would be the factor in those cases.

The OP isn’t that far from the meter.

He doesn’t need a 2” service, I think it’s funny that it was even suggested.

But whatever, if the OP wants to waste his money, fine with me.

The number of bedrooms and expected occupants would be the factor for me in this case. I work in homes with many bathrooms, it doesn’t mean they’re all going to be used at once.
 
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