Collecting Water with Rain Barrels and A Scrubber

rb1NOTE: This article was previously posted on Your Preparedness Story. 

When I was a kid, we didn’t have city water. We had a cistern as many in our community did. However, our cistern was not so good, it was made of cinder block, leaked and had to be cleaned at least once a year. Also, instead of just collecting water we had to have water delivered. The guy who delivered the water simply went to the local fire department where there was a self serve city water filling station. Because our cistern was not so great, and clean, we only used the water for cooking and cleaning. Our drinking water came from a local spring where a couple of times a week, we filled old milk jugs for collection.

Things I despised as a kid I now find somewhat enjoyable. As I have gotten older, I understand the pride of putting in a days work and it actually makes you feel better. I may be tired, but mentally I feel like a productive citizen. I also now enjoy gardening and cutting wood.  I know if the electricity goes out in the winter or the store shelves are empty, my wife and I can survive. In our community, there are a lot of people who still heat with wood and grow a garden. So I guess we aren’t really preppers, we are just average people living a lifestyle. Part of being self sufficient is having water. Where we live, we get a lot of rain.  We do have some drought during late Spring to early Fall. But late Fall through early Spring offers a great opportunity to collect water. Fortunately, we also live in a state were collecting rainwater is legal.

My wife, being a horse lover, decided we needed a barn. Thankfully as a kid I had a dad that knew how to work in construction among other things and made me help build several buildings. So, having the skill, I built a barn for the horses we didn’t have yet. The barn is 24′ X 72′. The roof is 14′ wide and 76′ foot long, times 2, that is roughly 2000 square-foot of collection space.  With the barn,  I convinced my wife to put gutters on the barn and get some food grade barrels. As of now, we only have 9 barrels. I am hoping to get a lot more. I have invested about 300 dollars for about 500 gallons of storage. A lot of the cost was in all the PVC/CPVC pipe and fittings.

According to information I found on the Net, 1 square-foot of roof space and 1″ of rain equals 1/2 a gallon. In theory, every inch of rain we get on our barn roof equals 1000 gallons. Where we live we get about 30 to 40 inches of rain per year. It might seem to make more sense to just buy a 500 gallon tank.  But what if that tank gets damaged? With individual barrels, you can compartmentalize.




The picture above is a picture of the roof scrubber I built. The principle is that the first rainfall washes the roof, dust, bird droppings, etc. and washes into the scrubber. The scrubber will fill and then all the clean water will flow on into the barrels. The scrubber is built with 3″ PVC pipe. The bottom of the scrubber is a cap with an 1/8″ hole drilled in the bottom. The hole allows the water to slowly drip out so the process can happen again. I made my scrubber about 18″ deep.  It probably holds a couple of gallons. The body is simply a 3″ pipe any length you want. The longer the pipe, the more cleaning.  Smaller roofs may not need as big a scrubber. The next part of the scrubber is a simple T. On top of the T I put some aluminum screen. I cut the screen lager than the opening.  The screen is held in place with a small section of pipe driven into the top of the screen. The only problem is that large items, mainly leaves, will collect and the scrubber may need to be cleaned periodically.


The barrels are obviously laying on their side. The barrels I used have a closed top with two bungs. The bungs have a small threaded inset in the middle that a 3/4″ threaded coupling can simply be screwed into. The back side of the inlet has to be but but that is a very simple process. I used 3/4″ CPVC water pipe like in most houses. I used teflon tape on the threads.

The top inlet requires a special coupling called a buttress thread adapter. The threads on the barrel are very course. I bought a bunch of these from this site –  Some places wanted as much as $20 a piece. As you can see in the pictures, one side the threads are very course and the other are fine.  A simple 2″ PVC adapter will screw in.



My barrels came with the bungs and have gaskets. The gaskets were not enough on some of my barrels and I used food grade silicon on the threads. I highly recommend this on all barrels. Do not over tighten the adapter.  They will break. I used 2″ PVC to connect the inlets on all my barrels, with 3″ off the gutters adapted down to 2″. All these items can be easily found at home improvement stores.

I got my barrels from a place that gets them from the local Pepsico bottler. I got mine for $15 dollars a piece. I doubt you will be so lucky. About the cheapest I found them are $50. You can order these type of barrels and many others from You can also buy IPC containers. They are square with a metal cage and hold from 275-330 gallons. They are $105 for the smaller and $125 for the larger one. Don’t forget you can also do this to setup a grey water system for your home.


Don’t forget insulation. We had cold all the way to zero this past winter and only had one problem. One of the valves busted, it was not insulated, but I put some silicon on it and it has been fine since. When water freezes it expands. When the ice begins to melt the expanded ice and water try to occupy the same space. In a closed space the pipes burst, but if you have space for the water to go you are unlikely to get a failure. One last note, in the picture of the barrels you can see a Y connector for over flow. I would recommend using a T instead of a Y. Also, at the end of the inlet section there is some pipe sticking up, that is for venting. A vacuum could possibly build up without it. I also duct taped some screen on the air vent to prevent bugs from getting in and possibly building a nest. I hope this article helps!


Anonymous Medic

This article first appeared on Ed That Matters.

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7 thoughts on “Collecting Water with Rain Barrels and A Scrubber

  1. James

    Good setup. I would recommend placing the barrels on cinder blocks if you can. This would allow room to fill water jugs.

  2. Interesting

    A couple of questions: 1. based on the size of your roof does the 1st flush system have adequate volume to “clean” the water before it gets into your tanks? 2. Are you concerned that because your tanks are white you might have a potential for algae? 3. Are you concerned about cross contamination since you don’t have a valve on the pipe between the tanks on the bottom? I’m asking these questions to learn more not to be critical. I’ve learned alot from the system I made for my 9×10 well house. I chose to have my tanks upright since I would maximize the the volume of water collected and not allow for oxygen to be present in the tanks. Your thoughts?

  3. Anonymous Medic

    I did consider the scrubber not being big enough, and it probably isn’t, but like I told a guy today, even if birds poop on you roof it take a certain amount of bacteria to be dangerous once diluted by the water it is unlikely there would be enough bacteria unless you just have a really weak immune system. algae was a concern but has not been a problem of yet. The top of the barn is relatively dark. As for height my plan is to eventually connect and have a pressurized system. Didn’t realize there were comments hope this helps.

  4. RayK

    According to your numbers, with 2000 sq-ft of roof space, even 0.1″ of rain (barely enough to clean the roof) would be 100 gallons of water. Your inflow scrubber is undersized if you really want to remove the sand and bird droppings.

    I’ve built a collection system with 4 IBC totes. I’ve put a PVC ball valve on each tank inlet and each tank outlet so I can isolate and treat each tank individually. The inlet manifold is 2″, the same size as the collection line. The outlet manifold is 1″, which is plenty large enough for gravity filling buckets.

    The totes, once filled with rainwater, are isolated by turning the inlet valve to the off position and I add an appropriate amount of bleach to make the water drinkable. The totes have a insulated shelter around them, so freezing and algae are less of a concern.

    Right now it’s a gravity flow system, but eventually I plan to add an inline pump and well system tank and tie it into the house piping.

  5. Illini Warrior

    in regard to that reference of using “food grade silicon” on the fittings …. really no such product on the market ….

    what it is “food safe” for the casual contact with food and it’s preparation and not direct & sustained contact – like in this application …. common usage is for sealing the edges of a countertop/sink or around built-in kitchen equipment ….

    there are products for this kind of application that’s food grade and compatible …..

  6. Dan Morgan

    I put faucets in my upright barrels about 12 inches up so sediment is below and I can fill a jug. On one barrel I put three faucets, one to get water out of and with a washing machine hose connect two more barrels. Pressure keeps them all at the same water level and I can close the valve anytime I dont want to use all three.

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