White bloches on leaves

[Beryl]

We have been having a discussion on the lottie today. Several of us have noticed white bloches (patches) on the leaves of various veggies (and some flowers) Leeks, celeriac, R. beans, etc. It doesn't seem to be doing any harm. The concensus of opinion is that it is the use of tap water spashing on the leaves then the hot sun.
Just wondered if anyone else has any ideas as to what might be the cause.
Thanks
Beryl.

[Beryl]

[Merry Tiller]

Tap water sounds favourite to me