Water line vs. water pressure

[Michael McCann]

I love this site man! I've been reading posts for thr past four hours. No really, FOUR hours, I can't believe people take time to help others like this. OK, now to my question...

My house was built in the 50,s with a galvenized water line to the tap and lead line to the main. My water pressure is currently 35psi. Water Co. says there is 70psi in my area, so therfore, I am responsible for replacing my line and they will replace their line at no cost to me. I want to be able to gain the highest psi level available especially to my shower on the second floor. Keep in mind I will be building another full bath on the second floor in the future.
I plan to use 1" copper line to the meter and from there what should I do to maximize the water pressure short of using a pressure assist pump? I am Instaling a new gas water heater as well. If I have to, I will replace the existing 1/2" copper lines inside with 3/4". Water pressure is of the most importance here. Thank you
Mike

 

[Phil H2]

The answer is not that easy. It depends on how many fixtures the pipe is supplying, elevation change, available water pressure and distance.

Here is a link to get you started:http://www.metrokc.gov/health/plumbing/wsfu.htm . The top table shows fixture units assigned to different fixtures (some codes assign slightly different numbers). The bottom table shows the minimum pipe size required for the quantity of fixture units, length of pipe, and available pressure. An adjustment must be made for elevation change. 1 psi of is subtracted from the available pressure for each 2.3 feet of elevation gain.

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[Sponsor]

 

[hj]

pressure

How are you measuing that 35 psi? If it is without any faucets running, then that is the pressure at the city main, regardless of what kind of pipe you have, or install. The dynamic pressure, which is what you should be concerned with, is a function of pipe size, pipe distance, and flow rate. Up to a certain flow rate, increasing the pipe size will have no effect on your pressure, so you have to determine whether the initial pressure is adequate before you spend any money replacing pipes and not improve your situation.

 

[Rancher]

If you measured that 35psi with no faucets open, then that's the max you will get... no mater how big or clean your plumbing is..

Rancher

 

[Verdeboy]

I was just wondering if "their" line is restricted in some way, thus reducing the water pressure that is actually making it into your home. I don't see why else they would start replacing pipes. I would let them replace their lines first to see if you get the promised 70 psi before changing your lines.

 

[Plumber1]

A restricted line will not change the static water pressure, but it could affect volume.

 

[Jadnashua]

To put it another way...with all of the faucets closed, the static pressure should be the same everwhere in the house. When you open a faucet, depending on the volume, the pressure may drop. An old galvanized line will eventually restrict the flow so much that it can stop the flow entirely.

 

[Verdeboy]

A restricted line will not change the static water pressure, but it could affect volume.

There must be a lot of dead rabbits in Plumberville, cuz there's a lot of "hare"-splitting going on around here. I don't care what the static pressure is. If water dribbles out of the pipe, the actual usable pressure is too low. So, I say start replacing the lead pipes and then go on from there.

 

[Cass]

There must be a lot of dead rabbits in Plumberville, cuz there's a lot of "hare"-splitting going on around here. I don't care what the static pressure is. If water dribbles out of the pipe, the actual usable pressure is too low. So, I say start replacing the lead pipes and then go on from there.

Thats why hj asked if the pressure reading he took was with a faucet opened. He hasn't responded back yet.

The dynamic would definitely be affected by rusting Galv. pipe.

 

[hj]

dribble

The lead pipe is probably the least likely spot for a problem. It does not rust or constrict, (unless a tree root grows around it and squeezes it shut. And if the city pressure is too low, he can put in a 6" main and will still not get any better results.

 

[Michael McCann]

I'm learning here...

The pressure was measured on an outside spigot with a pressure gauge. The water company installed a pump station about seven years ago before I moved in and they tell me that there is 70 psi AT THE HYDRANT. From your suggestions and answers I see a possible battle with the water company. I just need the ammo. Does an increase in water volume necessarily help water pressure and just because there is 70 psi at the hydrant does it also mean there is 70 psi at my line?
Mike

 

[Cass]

If you have 35# pressure, a 10 foot diameter pipe or a 1 inch diameter pipe will not change the pressure.

You would have great flow with the 10 foot diameter pipe but still 35# pressure.

Changing pipe size has nothing to do with static pressure, just the flow of water at that pressure.

Static pressure would be the pressure reading in your house with no one running water while reading the gauge.

You can't have 35# static pressure in your house if it is 70# on the street UNLESS there was a break in the line B4 the meter that no one knows about / can detect.

If that were the case then your reading would be a dynamic one but you wouldn't know it.

Very unlikely, but possible.

 

[hj]

pressure

YOu would also have an astronomical water bill. The only two ways you could have 35 psi if the main is 75 psi is if you were on a 100' high hill above the main or had a defective pressure reducing valve between the meter and the hose valve where you measured the pressure.

 

[Shacko]

Water pressure

What you have to do is to check the static pressure at the meter and the pressure at the hose bibb, that is the underground loss. If you have near 35lbs. at the meter there is no way to increase the pressure without a pump. Lots of luck.


----------------------------------------------
"If all else fails, read the directions"

 

[Michael McCann]

Final question????

I understand galvenized pipe corrodes and possibly leaks after about 40 years. Pipe is over 50 years old. So, if the galvenized line coming from the tap and to my meter is corroded to the diameter of a pencil, would it be worth changing or should I just buy a pump assist. I will be doing the work myself; estimated costs are:
$300.00 for copper pipe and materials
$100.00 for friend to dig
$ ?????? my time
$400.00 Total

WORTH IT GUYS?
Thank you
Mike (Future HVAC student)

 

[Cass]

Yes, replacing galv. pipe is a good idea on a house that old and will improve flow. Not sure what size you are thinking of useing but I would go with 1".

How is your friend going to dig the line?

 

[Gary Swart]

No doubt about the need for a new supply line. Galvanized pipe was state of the art years ago, but since it is subject to rust and corrosion, it has a limited lifespan. I'm a bit skeptical that you have 70 psi delivered by the city but only realize 35 psi. It would take a major leak to lose that much pressure and the meter would be running overtime. I would replace that old line with 1" copper ASAP and check the pressure then. Actually, 70 psi is a bit higher than normal, but perhaps not so high that you would need a pressure reducer. At any rate, that would be a bridge to cross after the new supply line. I would suggest you not rush into replacing the 1/2" copper pipes inside with 3/4" until after the new supply line is in either. The necessity requires a study of the number of fixtures on each line, and it may or may not be necessary. In other words, don't do more than necessary. If the city will deliver 60 to 70 psi, you will have plenty of pressure, and a 1" supply line will give you plenty of flow.

 

[Michael McCann]

Digging Answer

Yes, replacing galv. pipe is a good idea on a house that old and will improve flow. Not sure what size you are thinking of useing but I would go with 1".

How is your friend going to dig the line?

He has a backhoe. I plan to move the line and H/W heater all to a new location on the side of the house where all water fixures are located in basement, first floor and second floor.

 

[Michael McCann]

Project is a go

OK everyone - I took in consideration all the info you guys gave me and the project is underway as soon as it stops rainning here. I will replace the main line with 1" copper and let you all know the outcome. Thank you
Mike

 

[Plumber1]

Instead of whatever your area is.

While your doing that, why don't you get the city to come out and put their gauge on your sillcock and show them exactly what pressure is at your house.