ghosts in the plumbing!

Ok- had a new one today…

was filling a whirlpool tub so I could check it and noticed a low pitched whistle/ howl coming from the supply pipes. I shut off the water and the noise continued and got louder for a second or two then stopped.

I couldn’t get it to do it again. I checked over the pipes in the crawl space and found no issues. Any thoughts?? I’ve had knocks, bangs, chatter and gurgles, but this was the first whistle/ howl.

Check the water pressure. If the tub has not been used in a while, there could be some pipe/faucet build-up or lime. Is there hard water in the area? Newer faucets are constructed of plastics and rubber seals, and just do not like hard water or high pressure.

Our toilet just had the same issue. There was debris lodged in the bowl fill tube.
Most likely, there was debris somewhere in the supply and most likely got cleared out when you used it…probably for the first time in years!

Mine: was whistling outside at the main and you could hear the whistle in the house. When I checked the pressure - 110! Recommend lower the pressure.

Check the extrol (expansion tank) on the water heater.
have encountered this before
ruptured bladder in tank
replacement corrected.