Water pressure question

My wife and I recently bought an 83 year old house with some needed fixes that we mostly knew about ahead of time... but as neither one of us has ever actually owned a house before, we're learning certain things as we go along.
I know basically nothing about plumbing. Before we moved in, we had an inspection done (which I unfortunately couldn't be present for) and the inspector noted low water pressure that he said was caused by "galvanized water mains". I went back and checked the pressure and it seemed fine. Had a plumber look at it and said it looked fine to him too. (He didn't actually do a pressure test, just ran some water.)
After moving in, we pretty quickly figured out what the inspector was talking about. Run one water source and the pressure's fine - not great, but fine. (It's a little low when running something like an outside sprinkler, but fine for showering or dishwashing.) Try to run two sources at once, though, and both drop to a trickle. Downstairs sources seem to get about a 65/35 split if I've got the first and second floors competing with each other. Run the basement washing machine and flush the first-floor toilet, and you basically cannot take a shower at all for about 10 minutes. But even when running two sinks on the first floor, the pressure drops noticeably. Potentially more annoying, my shower head on the second floor seems to be suddenly getting clogged up with specks of rust. It was fine for like six months, but within the last 2 weeks or so I've got water jets going everywhere and occasional small bits of rust popping out.
I guess my question is, does this sound like a problem with the pipes coming in from the street, or with the pipes in my house? The pipe from the street is huge, and I can't believe it would be blocked up that much - it's gotta be eight inches around, and appears in basically decent shape to me. It does look like it's probably original to the house, though, or at least very old. Our house is also very close to the street and most of the pipe itself is contained within our basement, so it hasn't been exposed to exterior water or tree roots or anything like that.
The pipes inside our house are basically all clustered in one area; the washing machine in the basement, first floor bathroom and kitchen, and second floor bathroom are all basically in one vertical line going up. I guess I'm hoping that there's just one nasty old little pipe that needs to be replaced and that would solve the problem. Am I just dreaming or is this possible? How much might this repair cost?
And what exactly does the term "water main" refer to in a house? (I'm from NYC; to me, a water main is a 15 foot cement pipe carrying water to three million people.) Is it the pipe from the street or a central pipe carrying water throughout the house?
I'm *really* hoping I don't have to replace that massive pipe from the street; I wouldn't even know who to call for that, and would imagine it would be a huge expense.
Thanks...
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snipped-for-privacy@yahoo.com wrote:

I'd stay away from that plumber. From what you've described, it's pretty easy to fiure out there is a pressure problem. All you have to do is tun on a couple faucets at the same time. It's well known that galvanized pipe, which was used in older homes, will corrode from the inside out. Over time, the inside gets clogged and the flow reduced.

No way the water supply to a house is an 8 inch line. Are you sure you're not looking at the sewer line? In any case, the outside of a galvanized pipe isn't a guide to what it's like inside. I'm sure a google search will come up with lots of pics of corroded galvanized pipe.
It does look like it's probably original to the

Impossible to say. It's not likely however to be just one little section. Tytpically you need to replace all the galvanized pipe inside the house with copper. If the line to the street is shot, that would have to be replaced too. However, it;s more likely it's within the house, as the pipes there are smaller and will become more restricted.

Not clear to me either. I would call the line coming into the house the water supply line, or street line. The pipes withing the house I would just call water lines. In reality, the inspector may have simply meant all the galvanized pipe visible, as he may not have been able to narrow it down. I'd find the biggest outlet that is close the incoming supply line and see how much flow you can get from it. If it's real good, then that would mean the supply coming in is OK.

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snipped-for-privacy@yahoo.com wrote: <snip> The pipe from the street is huge, and I can't believe it would be blocked up that much - it's gotta be eight inches around, <snip>
Are you sure that is the supply line?
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snipped-for-privacy@yahoo.com wrote:

<SNIP>
Been involved in many of these.
Basically, *no* one on Usenet can tell you what steps to take. Other than to seek out a plumber who is competent to truly investigate and find the source and scope of the problem.
Don't just jump in and contract to have all the galv in the house replaced. May not solve a thing.
He should:
Determine the service lateral size and material. Do tests to see if the flow from the service line is sufficient.
If it *is* OK, then move to the bldg supply lines. See if there is possibly a single restriction near the service entrance which is causing low flow. Move on from there to the branches and make suggestions on how to proceed.
Jim
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People have wildly differing thresholds for "fine" in this regard. Some will regard "good flow" from each valve/faucet to be adequate, and not consider multiple faucets at once.
As mentioned earlier, there's really no way we can make concrete suggestions, because the causes/cures can be just about anything, with costs for repair ranging from almost nothing (more fully opening a shutoff valve) to enormous amounts (replumbing the whole house)
You need to find a trustworthy plumber, or someone similarly experienced, who can come in, properly diagnose the problem and identify a reasonable solution. Have him _show_ you why he thinks he's identified the problem.
"galvanized water main" sounds like the inspector thinks the line from the street is at fault. Without full testing, it's difficult to tell whether he's right or not, but at least he's identified the main line as galvanized, and galvanized pipe often cruds up over time. As does copper pipe (but much more rarely).
That doesn't have to be expensive. In many areas, the water utility has what are called "thumpers". These units will quite often do a reasonably good job of flushing out the build up. The trick is convincing them that it's degrading your service unacceptably, and if you can manage that, the service is quick and usually free.
I'd give 'em a call. If that doesn't help, get a plumber in to diagnose the issue. _Demonstrate_ to them why you don't think it's acceptable.
--
Chris Lewis, Una confibula non set est
It\'s not just anyone who gets a Starship Cruiser class named after them.
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On Tue, 05 Sep 2006 19:39:48 -0000, snipped-for-privacy@nortelnetworks.com (Chris Lewis) wrote:

If it is the water supply line that's at fault, and for some reason you don't want to replace it, you can probably get acceptable results by putting in a pressure tank. Your static pressure sounds fine.
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On 5 Sep 2006 10:34:16 -0700, snipped-for-privacy@yahoo.com wrote:

Please don't say you paid for this.
Oren
"Well, it doesn't happen all the time, but when it happens, it happens constantly."
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snipped-for-privacy@yahoo.com wrote:

When talking about plumbing you have to be rather careful even plumbers use different names for the same thing. The main IS usually the pipe that delivers water to many houses. The water pipe from the main to the house is usually called the water supply pipe, the turnout pipe, etc. and also often called a main by some people.
I can't believe that the water supply pipe to the house is 8" in diameter, and I doubt that a main would run through your basement. But stranger things happen. The large pipe is probably not a water supply or main, but a sewer pipe. Your water supply pipe from the street would likely be less than 2" in diameter and modern ones are usually only an 1" or 1-1/4" pipe.
The best way to get rid of stuff coming down the pipe is to periodically flush it. Open one faucet fully (no faucet screen) for a minute or so, close it and move on to the next fauce.
I don't think you have enough information to determine what the pressure problem is. Ask people next door to you if they have pressure problems.
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George E. Cawthon wrote:

<snip>
<snip>
<snip>
I questioned that too then re-read it. He says 8" -around- which would make it about a 2" pipe. Still huge for normal house service.
Harry K
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George E. Cawthon wrote:

Well alright, that's probably true then. I never really followed the pipes with my eyes to see where they all go and/or come from. Strange that I've never noticed the actual supply pipe, though, although I may have just mistaken it for a regular house pipe if it's only 2".

They don't. I don't need to ask; I see them running lawn sprinklers in the front and back full blast simultaneously. I can't do that. I can't run one sprinkler with the same pressure that they get running two at a time.
I guess I'll call a plumber back here (I was going to anyway, was just hoping to get a ballpark before I ask a guy to come out), as I obviously don't even have any idea what's going out and what's coming in to the house. So I don't even know what to look at.
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<<...snipped...>>

<<...snipped...>> <...snipped...>

Just a note that the OP said "8 inches _around_", not 8 inches dia.
A 2 inch galvanized pipe would be roughly 8 inches around. Still a heckuva lot larger than the usual 3/4 or 1", but aa lot more reasonable than 8" diameter.
--

Larry Wasserman Baltimore, Maryland
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snipped-for-privacy@fellspt.charm.net wrote:

He said "around" but I don't think he meant "around" Eight inch around would not be "massive." See OP's comment just before yours in the thread, 2" is normal to him.
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George E. Cawthon wrote:

I meant 8" diameter. The colloquial "around", not actually measured around the outside of the pipe. I meant from one side to the other through the middle. It's a big pipe. But yeah, you've all convinced me that it's the sewer line.
I found my water "mains" this morning and I think I know what the inspector meant by that now. I don't walk to all four corners of my basement much, but I did today and I just followed the pipes coming out of my meter. There are two pipes coming from the meter that traverse the length of the house all the way from front to back where most of my plumbing is clustered. So maybe my inspector wasn't using the term properly, but these two pipes are what I'm betting he meant by "mains" (six months ago I could have just asked him, but he wouldn't remember now). These two pipes are about 2" diameter and are definitely not copper so most likely the galvanized steel he was talking about. They don't look that old, though, is the odd thing. But then, my pressure is not *that* bad. So maybe they're just starting to go.
Anyway, I will definitely get another plumber in, but at least you've all pointed me in the right direction and stopped me from having my sewer line ripped out unnecessarily :)
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It is real easy to check water pressure , you can even get a gauge adapt it to a hose and get a pressure reading, Check it at deferent times during the day that will give you an average. But were you are getting confused your problem is not pressure it's volume, Your Galvanized pipes can be corroded to the point of a 1/4" opening you still can read adequate pressure. But you have no volume. Think of it like this you have a 1/4" pipe with 60PSI then you have a 2" pipe with 60PSI witch would more water come out of? Now chances are your pipes are corroded to the point of restricting the flow if the whole house is piped with galvanized pipe all the pipe is corroded to the point of needing to be replaced. A good plumber can explain this to you and it sounds like your in need of one. I will bet your city pressure is right on the money, but if you did a Gallons per minute test it be a deferent story. But what do I know I'm just a plumber
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