Drain has stagnant water in. Any ideas?

[Roofroofroof]

I have had a single storey extension built. The builder has been great. Looking at my gutter on the roof from the bedroom window I can see there are small pools of water sitting in the drain from yesterday's rain (today is dry). This water isn't draining away.

I spoke to the builder who said the gutter is water tight and will never leak. That there is 6 inches of waterproof material going up under the slate so it won't leak. But surely ALL the water is meant to drain away?

When it rains water does go down the drain but after the rain a small amount is left in pools.

Not sure what's to be expected. The architect didn't plan drainage (another story) so isn't much help.

That doesn't look stagnant! It's just clean fresh rainwater, which will either be washed away when it next rains or it will evaporate, nothing to worry about.

That’s a tiny amount of water - most of the gutter is dry? Unless I am seeing it wrongly.

Yes the water stays on the gutter instead of draining off as the gutter only has a very slight gradient. So leaves some small pools of water all along. I just wants sure this is how they are meant to be. I assumed all water is meant to drain away. My living space is underneath that area.

*wasn't

I thought I was going to see something similar to my drain issues! op - this is what stagnant water in a drain looks like. You are lucky, you have nothing to worry about 😊

Haha, yes, OP's is neither a drain nor stagnant.

Ahh sorry I meant gutter. But should a gutter run dry? @DrSpartacular

@TopicalNameChange ahh yes that does look stagnant and muddy!

The revised question is 'Should a gutter on top of a ceiling remove rainwater rather than sit in small puddles?'

That's fine.

Tiny puddles like that are not going to be a problem.