We Finally Figured Out How to Harvest Rain from Our Shingle Roof, Despite All The Deadly Toxins and Poisons

It’s a real buzzkill to watch all these prepper videos on YouTube show you how to build a rain harvesting system, only to realize that you can’t do it. Why? The rainwater from your shingle roof contains an ungodly amount of deadly toxins and poisons. Or maybe it doesn’t. But it probably does. We kept getting different answers. We emailed some rain harvesting specialists a few years ago and asked them if there was any way to do it. They said, “Don’t bother…” That felt conclusive.

Like I said, a real buzzkill…

And then there’s all the survival and homesteading guides that kinda tell you how to build a rain harvesting system, but not really…

My family brainstormed, but we kept running into walls. Then finally, we started piecing together a plan. After all, we’re not interested in drinking rainwater every day. We don’t want to spend tens of thousands of dollars on cisterns, pumps, and special plumbing. We don’t want to ditch the grid just yet. We just want a simple backup water source for emergencies, and now would be the time. If you’ve been going through the same frustrations, hitting the same dead ends, then maybe this post will help. We’re laying out the plan in maximum detail. We barely got any rain last week, and our barrels have already filled up. 100 gallons. We’re getting ready to send a sample off to a lab for a full test. (I’ll post the results here.)

Meanwhile, let’s get into it:

First, dig out your foundation. Add paver base and paver sand. This step helps you level the ground and provide a good substructure for your barrels. You want to dig below the topsoil and into the harder clay. If it’s too hard, soak the area with a hose and leave it for 24 hours. You can also use a pickaxe, but don’t swing it overhead like they do in the movies. Use it more like a hoe. Letting a 5 lb mattock drop into the ground will help break it up. Use a level to get the bare dirt as even as possible, but know that the paver base helps the most. Tamp it down.

We used 24 x 16 inch pavers for the base. They’re heavy as hell (50 lbs), but they’re worth it to create a large, even footprint. Lay cinderblocks on top. Two cinderblocks with one turned perpendicular match the paver size. The cinderblocks give you the clearance for hooking up hoses, filling up buckets, etc. You’ll put another layer of pavers on top for a smooth surface.

Remove the bottom section of gutter. You’ll probably have to unscrew downspout straps. You might be able to simply reconfigure your gutter pieces like the image shown above. We placed our barrels 2 feet away from the house to help protect the foundation. We wound up using a hacksaw on a downspout to get the right length. It can be frustrating to cut gutter, but it works. We tried aviation snips, but a hacksaw provided the cleanest cut. If you don’t want to mess with cutting gutter, you can buy precut lengths from places like Gutterworks.

Make sure to measure the gutter heights. You want a few inches of space between the barrel and the gutter exit. Remember that your gutter will be heading down at a 75-degree angle. Don’t use a 90-degree elbow.

Water will pool…

Some people skip this step and just buy diverter kits. We couldn’t find a diverter kit with consistent reviews. Biggest complaint: They’re either flimsy, or they don’t collect much rain during light showers. We’re building for extreme droughts, which means a free-flowing gutter. We also skipped the first flush. My full illustrated guide talks about them, but we opted for something simpler.

You can buy barrel nets that fit over the entire top part of the barrel. They’re easy to put on. All the debris from the first gutter gush ends up on the net. You just pull it off and shake it. Your barrels will also have a mesh screen over the top entry hole. It’s two layers of protection.

You can buy rain barrels from almost any hardware or big box store now. We decided to go with Epoch. They have a strong reputation. They use upcycled food barrels. Ours arrived clean, with all the parts already installed. We could’ve drilled out the holes ourselves, but it can be a real hassle if you’re also digging a foundation and working on other projects. These are tough barrels that will last a long time, and that’s the goal. They’ll take a beating. Remember, these things will be holding hundreds of pounds of water when they’re full.

You can link the barrels at the top and bottom to ensure they fill at the same time. Just add hose splitters to the faucets. Get a short hose for the top link. You can cut it and then add a female hose repair to the other end. You technically only need one splitter, but two means you can draw water from either barrel. The second barrel is probably going to have the cleaner water.

Unfortunately, most preconfigured barrels come with tiny garden hose outlets for the overflow. They’re not going to handle a major storm or a flash flood if you’re using a free-flowing gutter. Companies assume most people will be using a diverter kit. If you’re using a full gutter, then you need a bigger overflow. We did the math and arrived at a 2-inch hose. Combined with our two-barrel system, it can handle up to 3 or even 3.5 inches of rain per hour. Believe it or not, even during a drought, you can expect some pretty intense surges. That’s part of the problem. The rain comes in short bursts and flash floods. It’s not steady. You don’t want a flood to send water gushing over the top of your barrels. It’ll soak your foundation and ruin all that hard work. It’s not easy to find a 2-inch heavy duty hose, but we finally got one from Gloxco with a male NPT nipple. It’ll fit right into a 2” bulkhead union. For that, we’re drilling a 3-inch hole on the backside, just the first barrel.

A closeup of the hose splitters. Pretty standard. But if you want a heavy duty one that’s lead-free, try Morvat.

The hardest part was coming up with a way to filter the roofwater. Most pump systems we looked at were expensive and impractical on a budget. Then we got the idea to use a battery pump. It would give us the pressure and gpm needed to push the water through inline hose filters. While a battery pump will ultimately overheat and die if you run it like this for hours, we’re not doing that. We’re running the pump long enough to fill up a bucket for emergency drinking water. Or we’re running it long enough to feed our plants with a soaker hose. That’s 10-15 minutes max. The filter setup looks complicated, but it’s not that bad.

• First, add a 60-mesh hose filter to the pump intake. This step keeps grit from the barrel water from ruining the pump. The phrase “60 mesh” means 60 openings per inch of screen. You can go as high as 400, but don’t. If the screen is too fine, it can choke pumps and deflect water.
• Next, a Camco tastepure filter (20 micron) acts as a sacrificial first defense. It removes finer sediment. It also strips out some of the VOCs and heavy metals. Its main job is to protect the other filters.
• The Envig Catalytic KDF55 uses a stronger type of carbon that strips out a lot more VOCs and heavy metals.
• The Clear2O does a final sediment mop-up to catch anything that got through the first two filters, including any carbon particles.

These filters don’t strip out any viruses or bacteria. They do prefiltering for our gravity-fed setup at the end. You can add a little beach (about 1 ounce) to each full barrel to help knock out those threats early. Be careful. Bleach can interact with roof runoff to create toxic byproducts. That’s another reason why you have to do so much prefiltering. The good news:

All of these filters use garden hose thread. They come with garden hose attachments. So does the pump. You don’t have to fuss with adapters.

Simple.

Battery pumps offer convenience, but you might wind up in an emergency with no power and no water. That’s why we got a manual pump. It took a long time to find something capable of delivering the right pressure to push through three different inline filters, but we finally landed on the Bosworth Guzzler. There’s a model with a short handle for around a hundred bucks. It’s moderately hard to operate. We shelled out the extra money for the upgraded version with an extended handle, because… who knows? Maybe we’ll get injured. Maybe our kid will wind up needing to run the pump. The upgraded version makes operation way easier.

The filter line feeds into a bucket. We got 2-gallon and 5-gallon foodsafe buckets. Some days, you’ll want to filter several gallons. Other days, you’ll just want something light. For the hoses, we went with Camco 4-ft premium RV drinking hoses. They’re foodsafe. You don’t want to run standard garden hoses into your pump or your bucket. They can reintroduce contaminants.

On the filter end, if you need any adapters, look for ones made with lead-free brass or 304 steel. That way, you keep it all clean.

The inline filters remove heavy metals and VOCs, along with sediment. They don’t remove viruses, bacteria, parasites, etc. That’s where the gravity-fed systems come in. We spent a long time untangling all the claims and ad copy to find out which gravity filters actually do what they say.

Our conclusion:

Alexapure does the most. Their filters will strip out any remaining VOCs and heavy metals. They’ll also strip out viruses, bacteria, parasites, you name it. But you have to read the fine print. While the filter technically works for thousands of gallons, they only filter the really dangerous stuff up to 200 gallons.

Berkey/Boroux once promised a similar level of protection, but they ran into trouble with the EPA and had to remove their claims about viruses and bacteria.

British Berkefeld (Doulton) has the best certifications from NSF/ANSI for safe materials that remove lead and other heavy metals. Unfortunately, they don’t promise anything when it comes to viruses or bacteria.

You can find other gravity-fed systems, but all of them come with tradeoffs. That’s why we decided to go with Alexapure for our trial. We’re going to run this whole system, and then send the water off to a lab for testing. It’s going to tell us just how much we can trust our setup.

The entire setup costs about $1,000. That probably sounds like a fortune. I guess it is. But it’s a fraction of what a full system would cost.

Wells can run dry. Reservoirs take a long time to recharge. After fifteen minutes of rain, we had dozens of gallons of water.

We’re going to look at the results and then decide on the next steps. We might have to make some tweaks to the system, but we think it’s going to work. If it does, those of us cursed with shingle roofs might finally be able to make rain catchment work for us out here in the suburbs.

In a week or so, we’ll know for sure.

Let me know your thoughts…

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