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Old 08-13-2009, 01:06 AM  
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Default Simple Q & A session with newbie looking for advice

Hi everyone, i have a few questions about running fresh water lines up one floor to a sink.

I live in a 125 year old house on the Delaware river, 3 floors high with a basement...water heater, boiler, pumps etc are in the basement.

only first two floors are fitting with plumbing fixtures, the third was an attic with no running water.

is it possible for me to tap into the water lines in the bathroom below to run the sink? will i have enough pressure? will it drain correctly if vented properly?

basically my question is is it possible to do this without running lines from the basement 3 floors up i'd much rather tap into current supply if possible.

Thank you guys please dont bash on me too hard im new =(

(btw googled this and i couldnt find any solid answers, time to ask the experts)

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Old 08-13-2009, 07:34 AM  
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I'm not a plumber, but if you run off the existing lines, you will be adding friction loss and if both faucets were to be used at the same time, they would both certainly have less pressure than with only one running. The other thing is that you will lose .433 lbs for every foot you go up vertically.

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Old 08-13-2009, 10:55 AM  
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Welcome Gmoney:
Just as a rule of thumb; you can operate up to three fixtures off a 1/2" line without loss of pressure. If you can determine the number of fixtures on the line and the size of the line, you can work it out from there. There should be a 3/4" line into the house and to the first group of fixtures past the water heater, then the 1/2" lines serve as the branches. I would want to run the new lines from the existing ones too.
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Old 08-13-2009, 04:35 PM  
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What Glennjanie was saying about having only three fixtures on a water supply pipe is just what your local plumbing inspector considers "good practice", and it might even be part of the plumbing code as well. If you have more than that, the concern is that simultaneous use of all four fixtures at the same time will result in none of the fixtures having sufficient water pressure. It's not like there's any underlying scientific reason why you shouldn't have more than three. After all, if you look at the men's washrooms in schools and office buildings, it's common to see more than four urinals all supplied by the same 1/2 inch water supply pipe. They're counting on the fact that you're never going to have all the urinals flushing at the same time.

So, if you keep that in mind, and try not to use your attic sink when you can hear water being used down stairs and vice versa, then you should be fine.

Water has a density of 62.4 pounds per cubic foot at sea level. The surface area of the bottom of a cubic foot is 144 square inches. Therefore stagnant water has a hydrostatic pressure gradient of 62.4/144 = 0.4333333 psi per foot of height.

So, the water pressure in our upstairs sink will be about 8 feet time 0.433333 psi per foot or 3.47 psi less than in your downstairs sink. Winnipeg's water pressure is typically about 60 psig as measured at the water supply for the city, so a 3 1/2 psi drop is nuttin. In cities like San Fransisco, where you have 200 foot high hills, they have to have much higher water pressures because the people living at the tops of some of the hills there wouldn't get any water at all otherwise.

Last edited by Nestor_Kelebay; 08-13-2009 at 04:42 PM.
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Old 08-13-2009, 11:02 PM  
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New Jersey uses the 2006 National Standard Code.
Take a look at Chapter 10 section 10.14 and tables 10.14-2a & b at the link below.
2006 National Standard Plumbing Code On-Line PDF

Pipe sizes are dictated by fixture units and the tables list the fixture units assigned to different fixtures. This is done to keep the velocity of the water flowing in the pipe low enough that erosion of pipe materials, water hammer, excessive friction loss, and some other undesirable things do not occur.

Basically water supply is pretty easy. The tough question is what are your plans for the drains. Thats the hard part!

It's not quite as simple as tying into the vent stack that serves the fixtures on the floors below.

A permit will be required for work of the scope you are proposing.

Last edited by Redwood; 08-13-2009 at 11:12 PM.
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Old 08-14-2009, 03:28 AM  
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wow thank you guys for the advice seems like im definitly going to need a plumber for this job but its nice knowing these facts before going into it, you guys are great!!

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