Insulation for walls?? (to reduce noise)

Is it possible to insulate internal walls eg between a bedroom and bathroom to reduce the noise of water running toilets flushing etc.

Of course it is. Obviously there are different types of insulation. Standard insulation would help, but acoustic insulation would help more.
Wrapping insulation around waste pipes, etc will help dramatically reduce the sounds of toilets flushing.

It's something I did in my current home, and something I am doing in my new one.

Are you asking in regard to a wall being build or an existing one?

I have some left over roof sheet insulation (the stuff they put under the tin roof for insulation and help lower the noise of rain on the roof).

Can I put that in my internal walls to help lower the noise (currently have a few walls off at my house after getting asbestos removed)? The only problem would be that the insulation is 75mm and my studs are 70mm however I'd be using it more as a sound insulator than a thermal one.

Its for the house we are currently building. We one of the bedrooms is in between the ensuite and the main bathroom with both toilets up against opposite walls. I feel sorry for my poor child who will grow up in that room! Another room at the front of the house shares walls with the garage and laundry so we would like to sound proof these rooms but dont know what to ask the builder for.

Ohh that sounds like what I need. Can any kind of insulation be used. We are getting SilverCell in our roof which is the foil looking one. Would we have to use something else?

We are getting "Lafarge Soundshield Acoustic Plasterboard" to three rooms, it's part of our bonus items... but the tender does say the value for those three rooms is $1200. We are using it to (hopefully) block noise from tv room, to an adjoining bedroom.. and also for the rooms next to the laundry and toilet.
I'm sure your builder will have various options for this situation.... maybe it is something they will let you do yourselves. I have read on here about people doing their own sound (acoustic?) insulation.
I think the insulation for sound is different stuff from the usual.
Good luck buzz

If it was me, and I didn't want to spend the extra $$ on soundcheck plasterboard, I would buy some acoustic batts put them in myself just prior to the plasterboard being installed.

As already suggested you would be better off using acoustic batts like these

http://www.bradfordinsulation.com.au/Pr ... ernal.aspx