Fired up the power washer after a few years last week. Under current drought restrictions we can wash impervious surfaces once a week on our scheduled day. Got about 1/3 done last week, hoping to finish today. Got some streaks, since it was so dirty. Anybody have any recommendations for some sort of chemical to spray on before the next wash. I’m gonna go over it again to try to beat the streaks out. Used to spray some bleach, was wondering if there’s something better available.

I use Zep or Simple Green concrete cleaning solutions. I take the cleaner and mix it with water in a 5 gallon bucket. Then I dunk a stiff bristle broom in it and apply it to the driveway and lightly agitate with the broom to let it work into the concrete for a few minutes. I basically do a 8x10 section at a time before getting the pressure washer on it. And with my pressure washer, I use a pressure washer surface cleaner (which it looks like you have).

I've also used 30 Seconds Mold Outdoor Cleaner. They all work pretty similarly.

A friend has a power washing business and does a lot of driveways. He swears by the Simple Green industrial cleaner and degreaser, instead of the all purpose cleaner. He gets a walk behind or ride-on commercial scrubber from a rental business for really big jobs, and buys the 5 gallon jugs of cleaner. Two or three trips over the surface, and then power washes all the suds off.

Thanks for the replies! I’ve used Simple Green for some smaller, oil stains and had good results. I’ll give it a try on the driveway. I also have the back patio to do also.

word of caution, a pressure washer can remove the top slick coating/finish on concrete ... not knowing any better, I pressure washed our back porch years ago, thinking I was removing dirt/grime but in reality I was removing the finish of the concrete, left an ugly mess that my wife reminds me of frequently.

I’ve notice the sand residue after power washing, it’s better than the algae growth that needs to be removed.

I need to look into one of the walk behind or ride on units. It’s got to be faster than the power washer. I finished the driveway today, after the third Wednesday. Best results were with the wand and some Zep cleaner, but much more time consuming. the surface cleaner left a lot of streaks, but was faster.

Purple Power got rid of a giant oil slick on my driveway when it took me a few months to get around to replacing the rear main seal in my Sierra.