First get a toothpick, or unbend a paper click, and poke at the washer jets. They may just be clogged.
Otherwise, pry away the padding under the hood where the jets are located, you should be able to trace the tubes from there, and possibly see if they need replacing.
<span style='color:green'>Nobody likes you.</span><img src='http://www.bmw-forums.com/forum/html/emoticons/ph34r.gif' border='0' alt='user posted image' />
<span style='color:green'>Are you experienced, little girl? I want to know what goes on in your little girl world.</span>
<span style='color:green'>I'm the man! I'm bad, I'm so bad I should be in detention. I'm the man!!!</span>