The cold water pressure in the house dropped around three days ago and now there is no cold water coming out if the downstairs taps and the pressure in the upstairs cold taps is dwindling. Any ideas as to what is wrong and can I do anything to fix it? I had to turn off the cold feed to the downstairs toilet to change a syphon, could this be it? Also the overflow pipe had been leaking intermittently inside the house from the downstairs cistern just incase that sheds any light!