Our taps and toilets make a loud horn sound when taps are not open full and when toilets are nearing the end of filling up after a flush. We had a plumber come by who said the PRV outside our unit, near the water meter needed replacing. Its been replaced but we still have the sound. The PRV company replaced the valve again just in case it was faulty but that did not help either.
If the sound occurs regardless of which tap or toilet is used what could be the problem and how do we solve it?