There are a lot of people in Florida who have an interest in harvesting rainwater. We certainly get enough rain to make it a worthwhile activity.
Sometimes we get calls from customers who ask us what kind of roof would serve them best if they want to collect rainwater. Here’s what you need to know if you’re wondering the same thing.
You can harvest rainwater on any kind of roof.
There are more complicated systems out there which rely on overhead tanks. We wouldn’t really recommend those on a tile roof.
However, the type of roof that you have could impact the quality of the water you get.
Let’s be clear…any rainwater that you harvest is “grey” water anyway. It’s really only suitable for watering your inedible plants. (If you wanted to use the rainwater on anything you plan on eating you should probably purify it). If you’re feeling really “hard core” about your environmentalism, then you can gather it up and use it to flush your toilets.
You cannot drink it. Not without getting a really expensive, professional system that is designed to purify the water, turning it from grey water to white water. Most people do not install those systems.
But the Cockrell school of engineering did find that asphalt roofs and “green” roofs do add a whole lot of dissolved organic carbon (DOCs) to the water. Which is actually fine, as long as you don’t add chlorine in an attempt to purify the water. If you do, you’re going to wind up with a carcinogen. You’ll want to use some other method to filter the water before using it on your edible plants.
The impact is pretty minimal in the grand scheme of things.
In fact, we would only worry about it if you were, in fact, installing a system that’s meant to purify the water as well as collect it. If you’re installing a basic system you’re not going to purify the water anyway. You’re just going to carefully apply it to your plants and get on with your life.
Image credit: Sutichak Yachiangkham