No I don't think they are but...
Stupid questions I am sure,
Have you tried to clean the hole with a pin or something?
Are the hoses and water tank clean and not clogged?
Do you use an additive to the washer tank? If you do, what is it?
If a 'general detergent' is added to the water in the washer container, this can clog the lines.
If that all fails, then maybe, consider only using the window washer whilst travelling on the highway at around 100k/s, this should then make the water travel up the windscreen just a tad.