[pitcher]

Can anyone tell me the reason or what is the white spotted stains on a window and also the best solution to remedy the problem.

I have just quoted a job with this problem and they have blamed their current window cleaner, saying it was poor water quality.  The window cleaner used water fed pole system.    (The white spots do not rub off therefore I do not think that it is the water quality)

[pingu]

do you think they may water their plants with say a hose pipe and this gets on the glass?

Cheers
Dave.

[ftp]

If it's poor cleaning technique then the spots will be in trails very often one behind the other if it's more of a splatter with no definate run marks then it could be hosepipe or sprinklers etc.

[elite mike]

might be mineral deposits


virtually impossible to get off  

[R W C]

might be mineral deposits


virtually impossible to get off  

Was just about to say the same

[GWCS]

agreed, need to use a mineral deposit remover but not 100% removable.

[pitcher]

this is a 3story building so i wouldnt think its hosepipe water it s on all sun facing windows went there today window cleaner was there last thursday windows looked crap

[traps7]

Has someone waterproofed the brickwork/masonry? That will leave splash marks that'll look like spots.

[ftp]

have you tried cleaning a window with your wfp?

[karygate]

calcium deposits look like white spots that have to be scraped off. when first started they were on some windows ,once removed were fine but do not see them anymore on first cleans nowadays.