Rainwater Collection, One of Your Best Sources of Water

Of all the substances that this world supplies for our survival, the most critical is oxygen. If the Earth’s atmosphere runs out of oxygen, I’m afraid we’re all done for. That is probably one of the few survival needs that we can’t actually prepare for.After that comes water. If we don’t have enough water, we’ll only live about three days. But finding water can be a problemwhen the city water goes down. Fortunately, there is still rainwater.

Granted, catching rainwater will vary in effectiveness, depending on where you live in the country, as well as the season of the year. But regardless of where you live, you will get some rain, sometime. Regardless of how much or how little that is, catching it provides an excellent source of water for meeting your family’s needs.

Historically, rainwater catchment has provided a large part of mankind’s water needs. When a farmer builds a dam or digs out a hollow to gather water from a stream or that flows across his land, he’s catching rainwater. When a city, state or federal government builds a dam, creating a reservoir, they are doing the same. While this isn’t the only source of water we have, it has been an important one, especially for agriculture.

Harvesting rainwater literally means catching it as it falls. On a simplified level, placing a bucket out on the patio and letting the rain fill it up, is a rainwater catchment system. However, it’s a very inefficient one. That bucket will only catch the water that is going to fall directly into it. More buckets would catch more water, but there would still be a lot of rainwater that would get away.

We can improve upon that system by tying a tarp at an angle between a couple of trees, so that the water which falls upon the tarp flows down it and into the bucket. This is a great way of taking advantage of a rainfall when out in the wild, especially if you are in arid country, where there aren’t a lot of streams and ponds to get water from.

That same idea, of having an angled catchment system, is what’s behind the farmer digging a pond in a low point on his property. If you have a large piece of land, especially a hilly one, you can do the same. Simply look for how the water naturally flows off the hillside and dig a hole at the bottom, where it flows down to. Lining that hole with waterproof plastic sheeting could make it even better.

How to Harvest Rainwater Tips

 Harvesting Rainwater in Suburbia Building the Rainwater Catchment System

 But Collecting Rainwater may be illegal


Harvesting Rainwater in Suburbia

Most of us don’t have enough land for that, but we do have a man-made equivalent to that hillside. That’s the roof of our home. Water flows down the roof even better than the hillside, simply because it can’t soak into the roof like it can into the ground. But most of us let that water fall onto the ground, either directed by gutters and downspouts or simply falling off the end of the roof.

All we need is a way of capturing that rainwater and storing it, and we will have solved at least part of our water problem. How much of it we are able to solve will depend a lot on how much it rains and how big our home’s roof is.

People with one story homes have an advantage in this, in that they have a wider expanse of roof to catch the water, than those who live in two story homes. Nevertheless, whatever roof area you have is ideal for catching the rain.

Building the Rainwater Catchment System

If your home has a slanted roof and gutters, you already have something to catch the water. The rain hitting the roof will run down the roof to the gutters, where it will gather. Gutters are installed at an angle, so that they can transmit the water to the downspout. So you have that part of the system as well. But if you don’t have gutters and downspouts on your home, you’ll need to add them.

I guess you could say that a rainwater catchment system consists of three basic parts:

  • Something to catch the water
  • Something to transmit that water to storage
  • Something to store the water.

Since your main purpose for putting in those gutters and downspouts is to collect water, I would recommend putting in screens or leaf catchers on the gutters. While an extra expense, it will reduce the maintenance you have to perform, by preventing leaves and other debris from gathering in the rain gutters. This material will begin to decompose in the gutters, which could cause contamination of your rainwater.


Water Storage

You can literally store the water from your rainwater catchment system in anything that will hold water. I’ve seen people make cement cisterns, use above-ground swimming pools and use a variety of different types of plastic tanks. But the most common storage system I’ve seen is 55 gallon plastic barrels.
You can buy used plastic barrels cheaply and easily. Most will have the heads cut out of them and be cleaned out. While it might be nice to have a barrel that doesn’t have the head cut out, there is no real way of knowing that it is thoroughly cleaned, unless it is cut out.


The one problem with using plastic barrels is their capacity; they only hold 55 gallons. While that may seem like a lot of water, when you get a heavy rain, you’ll probably have the opportunity to gather much more than 55 gallons of water. Considering how much water we need to survive, you may as well collect as much as you can. To do this, you’ll need several barrels connected together.

I’ve seen complicated systems, where the output of one barrel connects to the input of the next; but the easiest way to connect the barrels together is at the bottom. Use a 2″ shower drain in the middle of the bottom of the barrels as the outlet. Connect them all together with 2″ pipe, PVC Ts and elbows, as shown in the photo. This is built for two barrels, but all it takes to add a third one is to put in a T, a little more pipe and another drain. With this sort of system, the barrels will all fill up at the same rate.

The output of the storage system is stepped down to connect to a 3/4″ ball valve. This size was chosen so that a normal 3/4″ garden hose could be attached. A smaller valve like this is also easier to control than a 2″ valve would be.

The barrels need to be on a stand, so that you can use gravity feed to get the water out. Otherwise, you’ll need a pump to get water out of the barrels. That’s either another physical task to do or another need for electricity. Personally, I prefer letting gravity do the work.

You will need to create lids for your barrels to keep things from falling into them and mosquitoes from laying their eggs in your water. This is easily enough accomplished by cutting some circles out of plywood. Just be sure to paint the plywood with several coats of paint, especially around the edges, to make it waterproof.

But Collecting Rainwater may be Illegal

There are some states which have made it illegal to collect rainwater. The EPA holds that all water which falls on your land belongs to the government, not to you. So, it is possible that you will get fined, if they find that you are collecting rainwater.

There’s a solution to this. All you have to do is make your tanks invisible. The easiest way to do that is to bury them. While making the project more complicated, it does have the advantage of being stealthy. This is great for your survival OPSEC.

The other problem with underground water storage is that you will need to have some sort of a pump to get the water out of the tanks, so that you can use it. I would recommend two pumps, an electric one for normal use, backed up by a manual one that you can use if the power goes out.

One Final Precaution

While rainwater may be some of the cleanest, purest water you can find, it may not be all that clean and pure by the time it reaches your storage barrels. Birds use your roof for a bathroom, as well as squirrels. The leaves that gather in the gutters will decompose, feeding bacteria in the process. So, you can’t be sure that your rainwater is safe for human consumption.

Always be sure to properly purify your rainwater, at least the water which will be used for human consumption. I doubt that bathing or washing your clothes with rainwater would cause anybody problems, but that which is consumed must be pure.

Dave Steen


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