Ever since they capped one of the sprinkler zones in an area that no longer needs watering, two of my toilets start whistling when the sprinklers are running and only stop when I flush them. How can I get this corrected?
Whistling toilets after plumbing alterations which occurs continuously except when flushed most likely indicates that debris was dislodged and is now affecting proper seal of the fill valves.
Turn off the water to each toilet, disassemble each fill valve, and give them a thorough flush by cracking the supply valve and letting water flow through, rinsing the washers and internal components. Heck, now is as good a time as any to go ahead and rebuild them by replacing all internal gaskets/washers.
I know this is an old thread but thought I’d share in case someone else has the same issue. Our toilet started making a whistling noise when our back sprinklers were on (they are the larger spray arm type). I can only assume they were affecting the water pressure just enough to cause it. We discovered the noise was coming from the part I’m pointing to. Hubby checked it over for damage etc but to the eye it looked ok, put it back together but same issue. So we bought a new toilet fill valve from Lowe’s for $8 and replaced it. Problem solved.