New construction vinyl siding

I have done a new construction home that has that light dirt/dust on the home and when the water dries the dirt is still there. Not sure if there is any detergent that would help break up the dirt so it would loosen itself from the vinyl siding. Advice would be greatly appreciated!

Thanks

What are you using in your mix now?

I just put some dawn soap in it to drag it down but that did not seem to work