Generally I have to say, that the Eco-friendly cleaning products I found so far are all designed to safely clean your laundry and indoor surfaces - not big outdoor cleaning jobs like your roof, patio or driveway.
I once was introduced to a great product which was based on citrus oil: I used it to clean the otherwise hard to clean off diesel spills on pumps in gas stations. It worked wonders. While the pumps cleaned off nicely, the wash-off had no additional chemicals and thus didn’t contribute to more groundwater pollution.
There are many good alternatives for chlorine on the market and I would like to use non-toxic cleaners as much as possible. Watching the recent video about the immense, pure groundwater supply we have here in Florida certainly made me not want to contribute to the pollution of this vast freshwater reservoir.
The problem I ran into was, that the natural cleaners work great but become really expensive when you need to pressure wash larger spaces. You need so much of the cleaner that it gets absolutely unprofitable. This is so unfortunate because I am sure many people would opt for a “green alternative cleaner” if it was just more affordable.
From what I saw and calculated, we are not just talking about an additional $50 but hundreds of dollars more and I don’t expect anyone to pay for that. Proof me wrong, if you like and I happily do it for you. ;-)
In my company we use a highly diluted mixture of 20% chlorine and 80% water. Other pressure washing companies use a 50%+ chlorine solution which gets the job done faster - it’s more concentrated but also more toxic. And while they charge the same as I do, we prefer to work with a less toxic solution. It takes a bit more elbow grease and probably double the time but we prefer it that way. Soaking the soil around your home with chlorine is never a good idea - so the less we use, the better!
In closing I want to direct your attention to one interesting product on AskTheBuilder.com, where the owner, Tim Carter, promotes his own environmentally safe product called ‘Stain Solver’. Apparently this is more potent than the usual oxygen bleach cleaners you can get in Walmart or Home Depot. You can check out his video here: