We have a power washer, but I didn't want to go through the hassle of finding it (since the move) and using it. Also, our water bill seems to be on the rise lately. So, I wanted to choose an option that wouldn't use as much water.
I filled a bucket with 1 cup vinegar, a squirt of soap, and warm water. I got a rag and started wiping. The mildew came off very easily!
I only used two small buckets of water. I used the water I washed with to rinse, by throwing it on the side of the house. I certainly think a power washer would've used more water, so I'd say this method was a great success!
At some point I'll probably need to clean the siding above the windows so I may use the power washer for that. Or, I may just use a ladder and a mop.
Does your house have a side that grows mildew? How do you usually clean it?