How to treat my water

Here is my city's website's page about their water treatement: http://www.ville.longueuil.qc.ca/vw/asp/gabarits/Gabarit.asp?ARBO_CATEGORIE_PERE_SEL=7%DF26%DF153%DF923&ID_CATEGORIE=923&ID_MESSAGE=6333&CAT_RAC=7

Now, they say that they use Chlorine gas in the treatment, and then Chlorine (Cl2) when it is in the pipes.

I will be doing an extract recipe soon and would like to know how I should treat the water. Should I boil all of it for half an hour ? (2x4 gallons to have about 6.5 gallons)? The owner of the LHBS said that the chlorine would simply evaporate in the beginning of the fermentation. The problem is, I absolutely need this batch to be as good as it can so I don't want to risk it. I guess I could only boil about 3.5 gallons before hand and the 3.5 gallons I will be using will boil off the chlorine while I'm doing my boil right?

Also, I'm pretty sure they don't use Chloramine right (which would require using campden tablets)?

I know it seems a bit hardcore, but this is my 2nd batch (I did my first with sterile water from the LHBS but for this batch I can't go get the water) and I don't want to have off flavors in it.

You could also let the water sit overnighht. We used to do this for goldfish, so that the chlorine wouldn't kill the fish. If you need such "perfect" water I would just go buy a few gallons of spring water from the super market. - Dirk

in your case, i wouldn't even worry about it. your extract already had the mineral content needed when it was created. chlorine in water is feared more than it needs to be.
I brew with chloramine treated water...which doesn't evaporate at all...it has to be chemically bonded/removed. But I don't even bother, and so far no one has noticed any chlorine related off flavors in any of my extract, PM or AG brews.

If you' can't sleep at night though, go ahead and use spring water from the grocery store...NOT reverse osmosis or distilled water though...its too mineral deficient.