Loud running water noise in gutter

[noseall]

... put a diffuser in ...

Interesting ... what's a diffuser noseall ?

Something that will slow the water down. Tying a rag to a bit of copper pipe slung over the running outlet will do the trick.

 

[Nige F]

I'll bet that the downpipe is almost overcome with water due to that valley discharging into it aswell as the eaves run . So it can be heard Particularly if that's the only downpipe

 

[MidsTW]

I'm with nige on that one. Don't think anything is wrong... It's just the shear volume of water running throught the system. There isn't much between the bedroom and the gutter so I'd expect to hear a little noise.

You could check that your gutter and downpipe sizes are appropriate for the area of roof you have to see if you are overloading that downpipe... Although with it being a new house I imagine it would.