wrote:
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.)


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.



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.

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
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?

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.




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?


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.



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...