Why does my standing well water leave a film or gunk?
Minerals like iron, calcium, or manganese in well water oxidize and precipitate out when exposed to air, forming a powdery film or sediment overnight. This common reaction makes the water look murky and creates buildup on basins, but it is typically a harmless aesthetic issue rather than a sign of contamination.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1covering the cup with cling film to test for dust
- 2cleaning cups with dental appliance or denture cleaner
- 3testing water quality
- 4Asking online forums for identification
- 5Checking for foul odors or active flooding
- 6dumping out the ice, washing the bin thoroughly, and cleaning with bleach water
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“I’m on well water and get my water tested regularly with no issues. This tiny film always appears if I leave water standing for about a day or more. What is it?”source ↗
“We have been caring for a family member's home that's been uninhabited for 6 months. Just found this in the ice cube tray of the freezer. Wondering what it is if anybody knows?”source ↗
“It is not hard and kind of disintegrates/melts between my fingers but does possibly feel a little oily.”source ↗
“i have a similar issue but mine is brown. eww”source ↗
“I noticed the water looked a little murky. Seems to be powdery black sediment at the bottom.”source ↗
“I lifted the float to test it was still working and noticed some gunk on it.”source ↗
“Do I need to be worried about the murkiness and gunk, or is this just how things are with the plastic basins?”source ↗