I have owned several cars over 12 years old. The washer fluid stream gets weak. A simple repair is to drain or pump out all the fluid from reservoir. Keep pumping until fluid stops coming out. Then put a mixture of half white vinegar and half water into reservoir. Push wash button until the vinegar mixture sprays out.
Leave it in over night and pump it all out the next day. The vinegar dissolves the calcium and gunk that has built up in the lines. The spray should be much better now. I have not noticed any damage to paint from the diluted vinegar.
One caution. If the pump is metal and badly corroded, cleaning out the lime and scale could cause it to leak.