Loud "rushing" sound in cold pipes when running ki

[andyste]

I recently changed the kitchen sink and mixer tap, and as the above title says, when I turn on the cold the pipes make a very loud "rushing" (or "shushing") sound.

It never did it with the old mixer tap, and the only obvious difference is that the new tap has small bore flexi hoses rather than copper tails. I'm assuming this is the problem, but is there any way to fix it other than replacing the hoses with tails (if it's even possible, given how small the threaded holes are in the tap)?

We've always had a similar noise when turning on a cold tap or flushing the loo in the bathroom & en-suite, although not as loud as the kitchen sink has got. Is there anything I can do to reduce this? It has a habit of waking the little 'un, as the rushing sound can be heard throughout the house.

Thanks in advance

 

[andyste]

No idea about the tap I'm afraid, it came free with the sink.

The noise only happens with the cold, the hot is fine (but it's a standard boiler to answer your question). The kitchen tap is plumbed in right by where the mains comes in. The strange thing is the noise is worse if the cold is only turned on partway - if that's any help for diagnosing.