Sometimes, when my toilet is flushed in the middle of the night, it will make a high pitched whining noise for several (5-10 seconds) while refilling. This doesn't happen during the day, and it only occurs sporadically in the middle of the night.

Can this be caused by higher water pressure during the middle of the night?

Could the temperature of the water be the culprit? It is mid-April right now, and the daily temps are just starting to get higher (like in the 70s).

I have attempted searches on the internet, and most point to the refill valve or ballcock assembly having issues, but since this only happens sporadically, and in the middle of the night, I am wondering if it could be some cause outside of the toilet.

  • Hello, and welcome to Home Improvement. It's hard to say what the cause might be, but the refill valve, plus a change in water pressure, sounds rational to me. And, you should probably take our tour so you'll know you'll know the details of contributing here. Apr 18 '20 at 16:53

In many areas water pressure is lower at night, to reduce leaks on the network. This will slow filling, and the valve might be 'dithering' at an awkward point, whereas under higher pressure it fills quickly enough to move over the awkward point quickly.

  • 1
    so, then, the valve is not getting the water pressure it wants and therefore whines about it?
    – Ack
    Apr 18 '20 at 19:03
  • Based off this response, it sounds like this doesn’t warrant further inspection/replacing anything. If the whining becomes more consistent, is that when I should take further action?
    – Kyle D
    Apr 19 '20 at 18:02
  • You can test this by slight tightening (closing) your shutoff valve. With the right tightening something should whine (either valve or assembly)
    – DMoore
    Jan 15 at 5:23

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