While some states such as Colorado have severe restrictions on the amount of rain that residents can save, Florida is not among those states. In fact, in West Palm Beach the use of rainwater collection systems is actively encouraged by the local government. Residents here can collect as much rain as they want, and the city actually gives away free rain barrels from time to time.
A major reason that rainwater collection is supported here is because Florida gets a lot of rain. In the summer (meaning the rainy season from about May to November) it can rain torrentially every afternoon. While the plants certainly enjoy the abundant supply of water, it makes it hard on the public drainage systems if they have to handle that much water. Any amount that can be stored helps alleviate the stress on these systems, so it’s in most areas’ best interests to allow residents to store the water.
(If you don’t live in Florida, odds are good that you can still harvest rainwater for yourself. This site has some information on state-specific laws, and most of the rest of the information that we’ll cover here will apply to you as well.)
The fact that it rains so much in South Florida is also somewhat of a blessing for those of us who care for our plants. Obviously the plants get watered often, but since it does rain regularly, anyone looking to install a rainwater collection system won’t need one with a large capacity to keep up. The abundance of rain means that even a small system will be continually filled, unlike rainwater collection systems designed for climates like those in Arizona where it may only rain six inches a year, all at once. In those situations, the storage capacity needs to be large in order to store water for much longer periods of time. Here, though, we can get away with much smaller systems.
In order to get the most out of your rainwater collection system, you need to think about what you want it to do. If you have a yard with 100% native plants and only want water to supplement something small like a vegetable garden, often a single 55-gallon barrel will meet your needs. If you have more extensive needs, such as lots of plants that aren’t as tolerant of the heat or sandy soils found in our area, then you may need something larger. We operate two systems on our property, one small and one larger, so we’ll go over the specifics of each.
Capacity isn’t the only important factor to consider, though. Since the only way to get the water out of the rain barrels is to use gravity to drain it out, you may need something like a pump unless watering by hand with a watering jug is enough. For smaller systems this is adequate, but if you want to use a hose or a drip irrigation system, you will want to consider installing a pump as well. First, though, we’ll look at how to build a single-barrel, 55-gallon setup that you can use to fill watering jugs.
For watering a small garden or even house plants, a single barrel can make a big impact. This is the simplest way to get started with rain barrels. You will need to tap in to one of the down spouts on your house, which is easy enough with the right kind of adapter. Then, run the hose to a hole in the top of the barrel. If you’ve gotten your barrel from West Palm, it’ll already have a spout on the bottom. If not, you can get a spout at Home Depot or add a bulkhead fitting and a PVC valve. You’ll also need four concrete or cinder blocks to set the barrel on, and that’s it.
One other thing to consider is overflow. If you’ve bought a diverter like the type linked above, this is already covered as the overflow water will just drain out the downspout like normal. If you’ve built something like mine, though, you’ll need to add an overflow spout to the top of the barrel, then direct the excess water away from your house with some piping. You may also like to add something to the downspout that will filter out leaves, if your roof has tree branches hanging over it.
I have another system on my property as well. This one collects water from my entire detached garage – about 300 square feet – and deposits it into three rain barrels. The barrels are linked by a manifold at the front of each barrel, which ensures the water is distributed evenly. While it is possible to put a system like this on concrete blocks as well, I opted to build it on a wood platform suspended by chain link fence posts that I set in the ground with concrete.
Each barrel will weigh somewhere around 600 pounds when full, so make sure whatever you build can support the weight. I did some back-of-the-envelope calculations before I decided how to build mine, and it’s been standing for over two years now. Plus, it survived hurricanes Matthew and Irma so it seems successful so far.
One of the benefits of building on a platform like this rather than on concrete block is that it frees up space underneath the barrels. This space also has moderate protection from rain and sun, so I used it to hold a 5 gallon per minute pump that’s powered by a 12V car battery. This allows me to have pressurized water from these barrels, which is enough to run a garden hose for watering plants or even washing the car.
The battery also supports some other equipment in my garage, like running the stereo, the landscape lighting, recharging my power tool batteries, and a few other things. It’s charged with a 160 watt solar panel that my neighbor allows me to leave on the roof of his back shed.
I also had to do some interesting things with the gutter system to get water from the east side of the roof to the west side of the garage where the rain barrels are kept.
This picture also shows the overflow for this system. It’s plumbed as 1″ PVC and drains to the front of the garage, where the downward slope of my property carries it to the storm drains on the street. At first I thought 1″ might be a little small, but since the rain barrels filter debris it’s proven to be more than adequate.
As for debris filtration: that’s what this 4″ PVC pipe in the last picture is. This is known as a “first flush” filter, and it allows the first rainfall to be diverted into this pipe rather than into the barrels. That means that any debris or bird poop or whatever gets sent to this temporary storage system first, and when the roof is reasonably clean the system will overflow into the rain barrels. There’s a further screen on the rain barrel itself, so the only thing that makes it into the barrels is relatively clean water. The first flush filter has a tiny pinhole in the bottom, allowing the dirty water to slowly drain out. I clean the filter at the bottom of this system about once a month to keep it working properly, but it is worth it for having to clean out the rain barrels much less often. My single barrel from the beginning of this post has no first flush system, and it’s a little more noticeable, but there’s no pump on that barrel so there’s less of a need for one.