response 2 of 22:

Nov 5 17:59 UTC 1997

Bear in mind that Ann Arbor has much cleaner, better tasting water than a sot
of cities, so your perception of "needing a filter" may be a bit off.  I've
been in small towns where the tap water tasted like swimming pool water!

response 6 of 22:

Nov 6 01:24 UTC 1997

Perhas one should run the water long enough to be sure that you arn't getting
the stuff that has been sitting in the city mains either ;-)  I wonder if
any of the mains are made of lead?  I wouldn't be surprised if some of those
pipes down there are close to 100 years old.  I wonder how many of the iron
pipes are packed with lead?  I also suspect that most of the old ones are
coated with a nice, protective, coating of calcium, lime, etc. like our hot
water heaters.

response 8 of 22:

Nov 10 12:30 UTC 1997

We have friends who had a water filter.  After a while (~1 year?) she
developed a rash around her mouth at about the same time that their
filter started giving off "musty tasting water".  After trying to treat
the rash with the usual battery of cures, she stopped drinking the filtered
water.  The rash went away and the filter became fill for some land fill.

response 10 of 22:

Nov 11 12:31 UTC 1997

That would explain it.  These friends were on a well.

response 12 of 22:

Jan 6 02:21 UTC 1998

We filter mainly to remove the chlorine and ammonia, which combine to form
a stinky compound that I can smell in my hair.  THe ammonia is put in to keep
the chlorine from evaporating - they combine to form chloramines.  Otherwise
city water is pretty clean, having already been filtered through sand and
charcoal.  They add chlorine just for insurance, in case something leaks in.
There are two kinds of carbon filter - granulated and carbon block, which
remove respectively 97 and 99% of the chlorine, when new.  After they get
filled up with chlorine they absorb less.  When you can smell or taste the
water coming through they should be changed!!!  Sears used to sell block
filters for $20.  We bought a case of them for $7 each, and can sell them to
someone for $10 (to account for inflation) or let you know the place to buy
a case of 20.  Old filters look brown, having accumulated enough particulate
matter in them that bacteria can grow in the filter, but supposedly they do
not get through the carbon block because the pores are too small.  But their
waste products get through and taste and smell bad.  You can buy a chlorine
test kit from a swimming pool place for about $8.  The water turns yellow when
you add a reagent if there is chlorine getting through, and then you can
change it before the pointt where it smells.  Or you can change it every year
just to be sure, if you don't want to test the water.  (Keep the test kit in
the fridge and it is good for many years).  We have put in a larger filter
(20" long, in a 'big blue' housing) to filter all the water in the house. 
These run about $35, I think, and one has lasted us several years, but for
typical usage you would change them at least once a year.  I can smell the
chlorine when I do laundry - like a swimming pool.  Our drinking water has
3 ppm (parts per million) chlorine in it, and home swimming pools only have
1 (municipal onnes have 3).  Chlorine forms carcinogenic compounds with
organic molecules, and destroys vitamins when you cook in chlorinated water.
And it tastes bad.  Write in for addresses for filters and test kits, I can
hunt for them.  You can also buy a bacterial filter, but ours has not
collected any bacteria for over two years.  City water is already pretty
clean, except for the chlorine and ammonia.

response 14 of 22:

Jan 6 11:42 UTC 1998

 
Yes it does.  We went on their annual tour this last spring and the
building where they ozonate the water is quite impressive with all
its stainless plumbing and ozone generators.  Since ozone is very
unstable, it can not keep the mains clean, as Rane said.  Amonia is
no longer added, from what I understood.  When I tested for it, over
a year ago, I found none.  (Water test kit for tropical fish.)

response 16 of 22:

Jan 7 00:56 UTC 1998

I don't know about the tours, but a few years ago I called up the water
plant and asked for their most recent test results.  They were happy to
send me the summary and a lot of details.  It made for interesting
reading.  Others concerned about the city water supply might want to
do the same, in addition to the testing they do at home.

response 18 of 22:

Feb 26 11:59 UTC 1998

They use to use chloramine but built the ozone facility to meet new
water quality requirements.  Now they just add a little chlorine to
keep the water disinfected while it travels around in the water mains.
Ozone is very unstable and can't do that job.

response 20 of 22:

Feb 28 04:27 UTC 1998

The ammonia reacts with the chlorine to form the rather unstable compound
chloramine. In effect, this reduces the immediate concentration of 
chlorine, thereby reducing the tendency to chlorinate other substances to
from things like chloroform, while providing a reservoir of chlorine 
that lasts longer in the water mains. This also reduces the amount of
chlorine that has to be added to ensure that a suitable level gets to
the far reaches of the system.

response 22 of 22:

Feb 28 18:36 UTC 1998

They add chlorine *and* ammonia. Chloramine itself is a highly explosive
liquid. The chloramine is formed in solution (no, its not explosive in
solution).