how do you get mildew off a concrete walkway?
Answers:
I have faced the same problem. Rent or buy a pressure washer. It will quickly remove the mildew and dirt build up. You will be amazed at how good your concrete walks will look. The only problem is that the mildew will return over time. Of course you cannot change the climate in which you live, but you can take some steps to minimize the reoccurance. Mildew likes damp and shady areas that are not subject to constant drying winds. Trimming trees and shrubs to expose the walks to sunlight will help. Correcting drainage problems will also help. If none of these options are available, consider the purchase of a pressure washer. An electric homeowners model can be had for under $150.00. You can then keep the mildew at bay as needed.
With all due respect to the other people who have answered this question, bleach is not a good solution. It is messy, smells bad, and is harmful to your landscaping. It is also a temporary fix since rain water simply rinses it away over time. It can also stain your concrete if applied too strong.
Good luck with your mildew problem.
Other answers:
dump a bunch of liquid bleach down brush it around with a broom, let stand 10 15 min. then preasure wash it off.
dump a bunch of liquid bleach down brush it around with a broom, let stand 10 15 min. then preasure wash it off.
bleach
lets make it 3 for 3, bleach!
ditto on the bleach thing. I here that oxyclean is also good for this...