do we need to filter water that come from our house pipe? why? and does it safe to drink it without filter?

Answer 1

Depends where you live. In Australia most tap water has already been filtered, as has water in the UK. I don't know about the US.
If your house pipes are old, or you live in an old neighbourhood, with old main pipes, then you could be getting a large amount of minerals and metals through your water. If you live away from a large city then during summer, the water may warm up as it travels through the pipes, particularly if the large pipelines are above ground. This could encourage any microbes to multiply to dangerous levels. In Australia, about twenty to thirty years ago we had amoeba getting into and growing in our water supply in this way; if it entered your nose, say when you went swimming, there was a chance of getting amoebic meningitis - often fatal. They now add chlorine to the water supply during summer.

In these cases you should consider getting a filter, particularly for your drinking water.