squealing from toilet when washing mashine is filling

Coveredinbees!!!!

as title, we have been experiencing a high pitched whistle from our plumbing for some time and I couldn't work out where it was coming from. By luck I happened to flush the toilet when the washing machine was filling and the noise stopped. Next time the washing machine started to fill I turned off the water flow to the toilet and again the noise stopped. Why would my toilet squeal when the washing machine fills?

I had the lid off the cistern and it has a bottom filling valve like this one

http://www.wickes.co.uk/Fluidmaster-Brass-Shank-B-E-Fill-Valve/p/118747?CAWELAID=120135120001173967&CAGPSPN=pla&utm_source=google&utm_medium=cpc&utm_term=&utm_campaign=Google%20Shopping%20-%20Heating%20&%20Plumbing&tmcampid=&tmad=c&tmplaceref=lzQbnSzV&tmcustom=mkwid|slzQbnSzV_dc|pcrid|43364569612|kword||match||plid|

chrisw

A bit like when you let the air out of a balloon, it squeaks as you stretch the neck due to a particular vibration frequency as the air escapes.

The washing machine drops the water pressure to the particular point where the water running past the rubber washer causes a vibration and hence a squeal. More or less pressure and you can't hear it. Changing the rubber washer might or might not remove the squeal. Try turning the valves off slightly.