Water run off stained render

[Qwertyqwerty]

The run off water from cleaning some pretty dirty windows has left a dirty streak down the white render. Is this normal or have I done something wrong? Also any ideas on how to fix it?

 

[Green Pro Clean Ltd]

If its just dirt off windows a hosing with custys hose should sort it. 

If you've let it dry a bit dip your wfp in some soapy water and have a scrub.  Sounds like its not been there too long so should come off easy. 

 

[Qwertyqwerty]

Thanks, I'll give that a go tomorrow