Water Pressure

[ch47dpilot]

If I put this in the wrong forum please let me know where it should go. Now for the question. I'm having city water put on to my 28 acres(required for the house). I'm going to have a 2" service installed since the price differences are small. I'll have to tun about 450-500 ft to where the house will be built. I've looked at some online calculators and I think if I go with 1.5" line I will only loose about 4-5 psi, assuming city runs about 20g/min. what does everyone think, is that a good number, is it too much pressure lose, or am I doing it over kill. Based my calculations from this site: PVC Pipe Schedule 40 - Friction loss and Velocity Diagram

 

[grsthegreat]

My house is about 300 feet back from the community water lines, and i ran 2" poly pipe. I have no issues with flow rates. My neighbor cheeped out and ran his at 1", and if he flushes the toilet while someone is taking a shower, one or the other goes waterless. Going too small is a BIG issue.

I was informed at the time by my excavator to make sure i used 2" lines, and boy am i glad i listened to him. There down 5 feet and id sure hate to have to excavate that twice.

 

[ch47dpilot]

That was my thinking, probably go with the 2" since you only want to dig once, granted here in Southern Alabama we don't need to go too deep but still 4-500ft is still a long way. Thank God I got a case trencher(4ft deep x 6-10"wide) for only $600. Anyone know if once you get in the house if you reduce to 1" if it will affect it that much. most of the PEX manifolds I've seen are 1" so figured I could reduce to 1" once in house to the manifold

 

[grsthegreat]

That was my thinking, probably go with the 2" since you only want to dig once, granted here in Southern Alabama we don't need to go too deep but still 4-500ft is still a long way. Thank God I got a case trencher(4ft deep x 6-10"wide) for only $600. Anyone know if once you get in the house if you reduce to 1" if it will affect it that much. most of the PEX manifolds I've seen are 1" so figured I could reduce to 1" once in house to the manifold

Most come into the house under the subfloor (Idaho again) and split it off to a 1" to the house and a 1" to the outside frost free lines. The house is piped 1" to the manifolds than run as 1/2" & 3/4" in house.

 

[ch47dpilot]

Thanks, that was my thinking, house is going to be really long so I'm thinking about 2 small manifolds, 2" into 2 1" lines to each side of house. Going to have to figure out which is cheaper but I think running the 1" to other side of house will be better. I'll probably cut the 1/2 & 3/4 PEX requirements in half

 

[kidr]

All your calculations will be for naught if you don't realize that pex is undersized. 1/2' pex is equal to 3/8 pipe. Go up one size using pex.

 

[ch47dpilot]

OK, I guess now I have a new question, if 1/2" PEX is really 3/8" what size is recommended for thing sliek your sink, toilet, ect. I thought they ran 1/2" copper or is it 3/8"? As far as the road to house that I plan to go with a 2" ID tubing of some sort, not sure what. What do people recommend, I've even seen them use PVC but I want as few connections as possible. When you bury it do you need to do anything to protect the tubing?

 

[grsthegreat]

Im not a plumber..im an electrician. But i work in alot of new houses here in north idaho. The house are all run (now days) an 1/2" and 3/4" pex tube. My house was built in 1996 and it was run in 1/2" and 3/4" copper,

Wish PEX was around back then. Anyways, all my main runs throughout the house (4,200 SF 2 story) were in 3/4" pipe and all runs up to sinks, toilets, etc were done in 1/2" runs.

Also, at the furthest point in the hot water run we ran a separate 1/2" run all the way back to the water heater to install a hot water recirculating pump. best investment i ever did. Not only do i get instant hot water, but i dont have to waste water by running the sink for 2 minutes while hot water gets to the back side of the house.

 

[ch47dpilot]

Viega | Plumbing, heating, gas, drinking water, drainage and bathroom design a new recirculation system, looks interesting haven't done any research yet

 

[boggen]

my best suggestion is contact a local plumber. and get them involved. they will be required regardless to do actual hookup between pipe to your house and the main line. and most likely the final connections on the water meter.

==================

GPM (gallons per minute ) is one variable
and PSI (pressure per square inch) is the other variable.

GPM would come from knowing your "peak water demand" say washing dishes, shower, washing cloths, flushing toilet. possibly a second shower going.

PSI would come from your local water company / city. contacting them, and they should be able to tell ya what the local pressure is for your area. and/or if they decrease water pressure right at the hook up between the main and pipe running to your house. or if they reduce pressure at the meter on your house. (assuming the first)

==============

bigger pipe is always better.

things to consider, multi showers running at one time, or possible dishes being washed, toliet flushed, cloths being washed, etc...

bigger pipe is always nice when dealing with filling up a pool, or having a outdoor lined pond. were you need to do weekly water changes.

other things might be a livestock water tank. for say a horse, or something.

================
bigger pipe is not always better when it comes to the physical water meter initial cost on side of your house. water company may charge a good amount for a larger pipe sized meter.

================
another thing to note. PVC pipe, to poly pipe to pex they may say 1.5" or 2", but the actual "inside diameter" of the pipe can be different!!

while pex is nice. having the right crimp tool and fittings can get rather expensive. it would have been nice to run pex here on the farm house, a few years back. and running each cold and hot water line, to each thing individually from pump room. vs running a single pipe and teeing off to each thing. but again more expensive than what i had at time.

one thing i did how ever, was install multi "shut off valves" so much easier to deal with things. and i ran 1" pvc main pipe throughout house for cold water, only reducing as i Teed off to goto, sinks, toliet, shower, washer. for hot water, to reduce how long hot water got shower (furthest away) i just ran a single 1/2" cpvc and teed off that to each sink, shower, washer.

recirculation pump placed on hot water line *shrugs* to me normally not worth it, or less large house say 4 bed room house. and the bathroom furthest away. i might then add a circulation line to that bathroom. but beyond that is it really worth it? to me no. so i wait approx 1 to 2 minutes. for hot hot water. the closer you are able to set the hot water heater to everything the better. a side note if you do, the recirculation pump for hot water. i would encourage insulating the hot water line. it makes a large difference.

 

[Tractor Seabee]

You are doing the 2" to reduce pressure loss. The water utility will install the size meter (probably 3/4-1") based upon yor demand (GPM) requiremeents not the pipe size. Difference in price of 1 1/2: and 2" is not much. Recommend you use Coiled polethelene pipe. You can get it in 500' rolls, no intermediate connections to fail. Go at least 18"-2' deep (unless frost line dictates more) and put in a tracer wire/warning tape above it; save a lot of grief down the road if it is dug up. . Ask the water utility what their minimum depth is as if it is not deep enough they will not hook up to it.

Ron

 

[grsthegreat]

You are doing the 2" to reduce pressure loss. The water utility will install the size meter (probably 3/4-1") based upon yor demand (GPM) requiremeents not the pipe size. Difference in price of 1 1/2: and 2" is not much. Recommend you use Coiled polethelene pipe. You can get it in 500' rolls, no intermediate connections to fail. Go at least 18"-2' deep (unless frost line dictates more) and put in a tracer wire/warning tape above it; save a lot of grief down the road if it is dug up. . Ask the water utility what their minimum depth is as if it is not deep enough they will not hook up to it.

Ron

thats depends....they put a 2" meter on mine... i bitched enuf

 

[TRR]

I've also heard that if you go to big on your pipe there won't be enough flow thru it to keep the water from getting stagnant. I don't remember what the flow rate was but it ended up somewhere around a 1.5" pipe. You should verify this because I can't remember where I saw it.

 

[grsthegreat]

I've also heard that if you go to big on your pipe there won't be enough flow thru it to keep the water from getting stagnant. I don't remember what the flow rate was but it ended up somewhere around a 1.5" pipe. You should verify this because I can't remember where I saw it.

hmm, not sure about that. My meter is hooking into a 12" line.

 

[clemsonfor]

Yea im thinking one shower and you will clear all the water out of the pipe under your house and all the way to the street, even if its a few hundred feet, that is unless you take a shower in 1:30.

 

[JRobyn]

In central TN, the "connection charge" from the utility district varied HUGELY for larger taps/meters into the trunk line. I think that my 3/4" connection was about $150, but for 2" was something like $2000. The utility district prices the connection based on the expected water use and evidently figures that a 2" tap is for industrial or large Ag users and it is priced accordingly. My install contractor told (a very skeptical) me that a 3/4 tap and meter would suit our needs (two houses) just fine, and so far, he has been right.

The contractor also installed my line from the tap/meter out at the road about 2500 ft to the house, using 2" 200 psi slip-joint pipe with rubber-gasketed ends. I thought that 2" would be more than I needed, but he convinced me to use it for two reasons - 1) he had a bunch of it on-hand that he sold cheap (significantly less than smaller stuff), and 2) that is what he typically installed FOR the utility district on smaller trunks. If it's good enough for main trunks for the utility, it is good enough for me. I have the advantage that the pressure at the tap is quite high (about 90-100 psi), so it will squirt a lot of flow through my "little" 3/4" tap/meter. And the tap/meter is about 90 ft higher in elevation than the house. So I have LOTS of pressure and need to regulate it down to reasonable levels.

 

[DK35vince]

I ran 1 1/4" plastic water line from my water meter to the house. (Around 880'.)
I had to add a regultor to get the pressure down to 40 PSI coming into the house.

 

[CurlyDave]

There is a very good reason to use the larger pipe size.

In most water systems it is highly recommended to keep the maximum water velocity under 7' per second. This is to minimize pipe erosion from rapidly flowing water.

I have never seen a system where this criteria did not result in a larger pipe size than a pressure drop calculation.

 

[SPYDERLK]

Yeah, but how large? 2" will do ~60gpm @ 7fps. Even 1" is way above houshold needs. Acceleration of long columns of water becomes pretty much an issue causing temporal surge losses w small pipes. Use of an accumulator tank at the useage end will prevent the toilet flush/shower issue as well as water hammer.
larry

 

[orezok]

My house is about 700' off the main. I put a 2" lateral in not because I needed the volume for my house, but to support a fire hose connection that is located at my house. Fortunately I have 140# of pressure at the main. I put a pressure regulator at the meter, but installed a regulator bypass valve to boost the pressure to full main pressure with the turn of a ball valve.

Wild fires being a given around here, I keep about 500' of 1 1/2" hose and while I would not try to fight a fire myself, I can soak down the entire area around my house before I bail out.