How dirty is tap water in manchester?

Do you mean manchester UK? The tap water across the UK is safe to drink and produced to a high safety standard. However, this does not mean that it always tastes good. Sometimes it may contain harmless minerals which give it a metallic taste or may be discoloured. In some areas people use bottled water for drinking for these reasons.

Are you referring to Manchester in the UK or New Hampshire?  Here is some

I've never been to Manchester, but I herd tap water is safe base on what I hear and stories told by some friends.

i never been in manchester sory........!

Its safe, but I advice not to drink it cause it didn't taste good.