1 Gather Your Materials
Before you begin, make sure you have all the necessary materials and tools on hand such as…
Rainwater storage tank or barrel
Concrete blocks or a stable platform
Gutter system and downspout
First flush diverter (optional)
Pipe and connectors (if needed)
Prescreen or filter (for keeping debris out of the barrels)
Garden hose or pipes
T-connectors and clamps
Post barrel filter (for keeping debris out of the pump)
2 Choose the Right Location
Select a suitable location for your rainwater storage tank or barrel. It should be close to the area where you plan to use the harvested water and near your gutter downspout. Ensure the ground is level and stable to support the weight of a full tank. 55 gallons of water weigh 460 pounds. We placed our barrels on cinder blocks as we have two water barrels that are connected.
This allows us to ensure both barrels are at the same height so that when it rains each barrel always has exactly the same amount of water in them. This also allows each rain barrel to feed into one another and can also feed the pump independently. This allows us to take one barrel off line to drain, clean and do maintenance while the other is fully operational.
To take advantage of the rainwater that flows off your roof, your barrel should be installed at the bottom of a downspout, either on your home, garage, or shed. Initially (before we built our first flush system designed) we had the barrels at either end of the deck directly below the downspout just to test out how everything would work.
You may need to cut the downspout above ground level and insert it into the top of the barrel with a hose or a pipe. Or create a diverter system like we did. Make sure the location you choose is level, stable, and accessible. You may need to use some brackets, straps, or blocks to secure the barrel to the wall or the ground. You don’t want your barrel to tip over or roll away when it’s full of water. You also need to seal any gaps or holes in the barrel or the hose with silicone or caulk to prevent leaks and definitely mosquitoes!
As I said we have incorporated a “First Flush” system that diverts the first flow of water from the roof away from our main catchment system and allows it to slowly drain away from the cabin. The first pass of water in any storm essentially washes your roof of all the sediments that have collected since the last rain, such as pollutants, debris, bird droppings, and other contaminants. By using this first flush system, you can protect your storage tank from contamination and ensure much better quality of your harvested rainwater.
We built ours using sections of 4″ and 3″ PVC, elbows, connectors, a shut off valve at the bottom of the main catch tubes and an empty water bottle inside the main tubes. The water bottle floats to the top and blocks the main tube off and thus diverts the remaining rainwater into the rain barrel. We leave the valve open a crack which allows the main tube that catches all the roof sediment to slowly drain after the rain has stopped. This resets the system automatically for the next time it rains.
We also built a “site glass” using a few PVC elbows and a clear piece of vinyl tubing so we can see how quickly the water is filling the system and also to ensure its draining as a rate we want after the rain has stopped.
The valve at the bottom allows us to drain the collection tube at a desired rate. Sometimes if we’re getting a big storm coming we will drain the rain barrels, leave the rain barrel drains open and leave the drains at the bottom of the main tubes open to fully flush out the system. it takes only an hour of rainfall to fill both rain barrels.
Here is a detailed video explaining the set up of our first flush system by YouTuber LDSPrepper…
3 Prepare the Foundation
If you’re using concrete blocks, arrange them in a stable foundation pattern to support the tank or barrel. Ensure they are level and well-compacted. For smaller barrels, a solid, level surface is sufficient.
4 Install the Gutter System
If you haven’t already, set up a gutter system on your roof to direct rainwater towards the downspout leading to your storage tank or barrel. Install a first flush diverter if desired to divert the initial rainwater flow and reduce debris entering the tank. You can install a small plastic leaf guard in the opening of the gutter drain or a complete gutter protection system.
5 Connect the Tank or Barrel
Position the rainwater storage tank or barrel on the prepared foundation. Ensure it’s level and secured in place. Connect the downspout to the tank’s inlet, one you’ve created, or have it drain over an inlet screen to prevent debris from entering.
6 Set Up an Overflow
Install an overflow system, typically a pipe or hose, near the top of the tank or barrel. This allows excess water to flow away once the container is full, preventing overflows or damage.
7 Screen or Filter
To ensure the stored rainwater remains clean, install a screen or filter over the inlet to catch any remaining debris. You need an opening large enough to reach in and clean out the inside either with a brush or wet dry vac. There are also filters you can incorporate before the rainwater enters the barrel like this leaf eater system.
We have also installed an in-line garden hose filter on the outlet side of the tank before the water enters up from underneath the cabin and into our shurflo water pump.
8 Regular Maintenance
Check your system periodically for debris in the gutters, screens, or filters. Clean them as needed to maintain the efficiency of your rainwater harvesting system. We drain our barrels once a month, use a wet/dry vac to get the very bottom cleaned out and also add a capful of bleach to each barrel to help keep the water more sterile.
By following these simple steps, you can install a rainwater storage tank or barrel that will last and function worry free for decades.