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Old 06-09-2011, 01:13 PM   #1
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anybody want to clear something up for me? Pressure


ok here is one for ya.

I live in a neighborhood that is known for bad water pressure. Not sure of the PSI, don't have a tester. It is to the point where you can't do two things at once or they will trickle. If the sprinklers is going and the toilet flushes they sprinkler goes way down to almost nothing. Same thing with the other fixtures. If the dishwasher/laundry is filling you can really take a shower.

Not sure if this is water pressure or water flow issue?

Whole house is 1/2" copper.

I talked to a neighbor who said he upgraded to 3/4" and it made a big difference.
does that sound like it would fix the issue mentioned?

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Old 06-09-2011, 04:29 PM   #2
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anybody want to clear something up for me? Pressure


Probably, however I would like to know the incoming water pressure.

I would buy a pressure gage attachment that fits where the garden hose hooks up and take the pressure there with no major water usage. Then I would start opening up water spigots and watch the gage.

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Old 06-09-2011, 04:41 PM   #3
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anybody want to clear something up for me? Pressure


First, you really need to buy a water pressure gauge and see what your incoming water pressure is. They are less than $20 and a good investment.
Second, do you have galvanized or copper water pipes?

That said, here's some statistics that might help you decide to upgrade to 3/4" pipe.

The area of a 1/2" pipe is: .196 sq inches.
The area of a 3/4" pipe is: .44 sq inches.
So a 3/4" pipe has 2.24 more area than a 1/2" pipe.

Also, my research indicates that it takes four times the power to move twice as much fluid per minute through the same pipe.

So upgrading from 1/2" to 3/4" pipe should make a big difference in your situation. After you verify your incoming water pressure, you might even want to consider upgrading using 1" PEX tubing for your trunk runs if your incoming water pressure is indeed low. Using 1" pex tubing would be much cheaper than using copper piping and IMO, would really be a good solution.

HRG

Last edited by Homerepairguy; 06-09-2011 at 04:43 PM.
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Old 06-09-2011, 11:22 PM   #4
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anybody want to clear something up for me? Pressure


Standard water system sizing for houses includes knowing what the static pressure is, the length of the system overall, and the number of fixtures.

Looking at a sizing chart, you will see that as the incoming pressure increases, you can use smaller pipes. The opposite is also true, however this means increasing the size of your system all the way to the meter or whatever else your source may be.
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Old 06-10-2011, 12:37 PM   #5
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anybody want to clear something up for me? Pressure


ok thanks for the advice. I had a few typo's in my original response but you get what i was saying. You can't do two things at once.

So I should get a tester first and see what the PSI is? Attach it to a garden hose check it then turn on another faucet and re-check?

So it appears that upgrading will in fact make a big difference?

I will by a tester, check and let you all know
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Old 06-10-2011, 04:31 PM   #6
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anybody want to clear something up for me? Pressure


It's not going to make one bit of difference. It's amazing if you spend the $ and time to redo all plumbing you will convince yourself, even if it wasn't worth it that somehow it was. Reminds me of my friends paying $46,000 to do geothermal and convincing themselves it was worth it. It's 300% efficient... yeah but electricity costs 300% more than fuel to do the same thing so it's a wash. If you ask them they think it was all worth it because they're paying $1,100/year for heating/cooling and it cost them $46,000 yet I'm paying $1,130 but I paid $7,000. I could do a whole lot of energy saving with the extra $39,000 and beat them.

Here's the problem(s). The diameter of the fitting to your toilet and sinks are 3/8ths. The only way you're going to increase the flow of water is to increase pressure. 3/4" is going to hardly do anything. Same with your outside faucet, which is typically 1/2", the piping to your shower head is 1/2". Absolutely everything in your house ends at either 3/8th or 1/2" so the only way to make a difference unless your pipes are full of crap is to get more pressure. Spend the $ on a tank & pump, that will do it.

Last edited by Piedmont; 06-10-2011 at 04:42 PM.
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Old 06-10-2011, 10:48 PM   #7
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anybody want to clear something up for me? Pressure


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The only way you're going to increase the flow of water is to increase pressure.
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Old 06-11-2011, 04:09 AM   #8
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anybody want to clear something up for me? Pressure


bfan781,

If you decide to upgrade your pipes to a larger diameter, start with the run from the city source to your house first. Use 1" for that run and see what happens. Then upgrade the size of one of your trunk lines in your home and see what happens. If you don't want to open up a lot of walls, just run pex tubing on the floor of you home for a test, though you will have to open up the wall in the bathroom. This would be the cheapest way to verify without upgrading all of the plumbing in your home to verify.

Homes in our area are plumbed in copper using the trunk and branch system, using 3/4" trunk lines and not 1/2". The 3/4" trunk lines are branched to smaller diameter lines at the receiving end to the fixtures.

Newer homes in sub-divisions like my nephew's home are plumbed in pex using the homerun system. The homerun system uses a source manifold that has 1" input from the city. The outputs from the manifold are individual 5/8" to each shower/bathtub and 3/8" to each faucet. One line for each fixture. That's the homerun method.

HRG
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Old 06-11-2011, 06:22 AM   #9
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anybody want to clear something up for me? Pressure


Before I spent any money I would call the utility company and ask them why it is so bad. It seems if it is the whole neighborhood they have responsibility to correct. But you need to know your pressure and your neighbors. Maybe they need to add a pump station, get the neighborhoood behind this, if you can't get anywhere then I would do as piedmont suggests.
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Old 06-12-2011, 03:35 PM   #10
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anybody want to clear something up for me? Pressure


Quote:
Originally Posted by Piedmont View Post
Here's the problem(s). The diameter of the fitting to your toilet and sinks are 3/8ths. The only way you're going to increase the flow of water is to increase pressure. 3/4" is going to hardly do anything. Same with your outside faucet, which is typically 1/2", the piping to your shower head is 1/2". Absolutely everything in your house ends at either 3/8th or 1/2" so the only way to make a difference unless your pipes are full of crap is to get more pressure. Spend the $ on a tank & pump, that will do it.
Piedmont,

I personally think that your conclusion is incorrect. You said that the only way to increase the "flow" of water is to increase pressure. The "flow" of water is dependent on BOTH pressure and pipe diameter. For instance (where gpm = gallons per minute in straight pipe):

GENERAL GUIDELINES:

In a gravity fed system:
1/2" pipe = 7 gpm
3/4" pipe = 11 gpm
1" pipe = 14 gpm

At 20 psi pressure:
1" pipe = 26 gpm
1.25" pipe = 47 gpm
1.5" pipe = 76 gpm

At 40 psi pressure:
1" pipe = 38 gpm
1.25" pipe = 68 gpm
1.5" pipe = 110 gpm

As one can see, the data above shows that water flow is dependent on BOTH pressure and pipe diameter. In a gravity fed system, going from 1/2" pipe to 1" pipe will approximately double the water flow. At 20 psi and 40 psi, going from 1" pipe to 1.5" pipe results in about 2.9 times the water flow. Since the OP is dealing with fixed pressure from his/her city, then to increase the flow of water the pipe diameter can be increased.

He/she would have to have a good diameter pipe size (say 1") from the city to his/her home first since a restriction there would negate any increase in pipe size for the rest of his/her home.

Also note that the dynamic pressure at the far ends will drop due to friction, elbows and pipe diameter. So again increasing pipe diameter also increases elbow diameters and results in less dynamic pressure drop at the far ends.

I do agree that increasing the pressure by using a tank and pump is also a good solution providing that the OP's pipes are not galvanized and full of crap. (Which is why I asked what kind of pipes he/she has in my original post.) But the OP's original question was about increasing pipe size and not about a tank and pump.

My take anyway,
HRG

Last edited by Homerepairguy; 06-12-2011 at 04:16 PM.
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Old 06-12-2011, 06:52 PM   #11
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anybody want to clear something up for me? Pressure


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My take anyway,
HRG
Your take is correct. Plumbing code books clearly outline this with sizing charts.

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