White slime clogging drain - what is it?

[ClematisBlue49]

Has anyone had this before? Every so often I notice about half a cupful of sticky white slime on the grille below drain pipes leading from the roof, boiler condensate pipe, and bathroom waste pipes. I'm in a hard water area, but it doesn't look like scale build-up.

Until recently I thought a the foxes were throwing up in the drain! But it happened today while I was in the garden with no foxes around.

Is it fat from pots and pans that’s got down the drain and gone cold?

If it’s from bathroom could be shower gel/shampoo?

Definitely sounds like fat.

If your kitchen waste doesn't enter that grille then I am going to assume it's something from your bathroom rather than boiler or roof. What products do you use on yourself and for cleaning?

Thanks all.

I don't think it's fat because I am scrupulous about wiping plates and pans before washing them, after a blockage about 10 years ago. I don't think it can be from soaps or shampoo (I shower at night).

The only thing I'd done between seeing the drain clear and the slime appearing was to wash my hands quite thoroughly in warm water after gardening (with hand gel). So I'm wondering if the warm water from the sink might have washed down facial cleanser / toothpaste from earlier. It's weird that it doesn't happen often, but then I generally wash my hands with cold water, which may make a difference. I was worried it might be related to the boiler (some sort of sludge), but it was serviced last month so hopefully not.

NB I'm selling my house currently so quite paranoid about things suddenly going wrong! 😕

I hear you about things going wrong when selling!

Based on what you've said i think its likely to be the hand gel as I expect you used more than normal if you've been gardening. The boiler would be brown rusty coloured sludge so not that.

Thank you @AutumnFroglets , that's very reassuring about the boiler.

I'm going to put some Bathroom Unplugger down the sink to make sure the pipes are clear, as that does seem the most likely source.