How to Harvest Rain Water in a Household Setting

Two Parts:Setting up a Collection SystemCreating a Storage and Retrieval System

Water is a precious resource in many parts of the world. Even where it is not scarce, using purified water on your garden or lawn seems wasteful (not to mention expensive). Rainwater can be used for a variety of uses, and as long as you know how you can collect it and save it for use at a time of your choosing. This article will explain methods you can use to collect water at your own home.

Part 1
Setting up a Collection System

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    Create or identify a surface suitable for rainwater collection. The easiest way to collect rainwater is to channel the water that runs off of a broad surface. This surface is known as a "catchment area."[1]
    • The most commonly used and easily adapted catchment area is the roof of a house. In some states that heavily regulate water collection and storage by individuals, this is actually the only legal catchment surface allowed for rainwater collection.[2]
    • Because rainwater can collect at the base of any sloped surface, the options are quite varied. You may even notice that water forms a temporary stream as it runs down the gullies of a hill on your property. This water can also be collected and stored for later use.
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    Set up a collection point for water on the catchment.
    • In the case of your roof, the gutters of your house may already serve to collect the water. They catch the water as it runs off and thus allow you to capture it for your own use.
    • For the hypothetical hill example referenced earlier, you can excavate a wide but relatively shallow hole or basin at a point in the gully. The water will collect there as it runs down the natural channel.[3]
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    Connect the collection point to a conveyance system. Quite simply, the "conveyance system" is just some form of tube or channel that transports the water to a storage unit.[4]
    • Most gutters already have some form of piping that is used to expel the rainwater a distance from the foundation of the house. However, most such arrangements are inadequate for the requirements of rainwater collection. If the water should become backed up in the tubes, the water could overwhelm you gutters and either spill over or weigh down the gutters to the point where their braces collapse. If you live in a high rainfall region or one in which rains come down in sudden bursts, you must have high quality tubes or pipes that lead to the storage unit.
    • If the water collection point is at ground level, you can dig a channel that leads to a storage unit. However, keep in mind that the channel must have a sufficient slope to keep the water moving. That fact may ultimately determine the location of you collection point.

Part 2
Creating a Storage and Retrieval System

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    Install a storage system that can work close to your home. The biggest barrier to rainwater collection is the matter of storage. It is only useful to collect rainwater if it can be done in large quantities, but it is not always easy to determine the best means of doing so.[5]
    • Above ground storage options can be as simple as a barrel, or a number of barrels connected in series.[6]
    • Alternatively, you may choose to use a single large underground tank or cistern. Because of the size of any water tank, it may not be the item that you want in your backyard. In these cases, it could be best to excavate a sizable area for the purpose of installing an underground tank. The use of an underground tank increases the likelihood that soil or pollutants will enter the water as small cracks or breaks appear in the tank or pipes. However, if you have limited space this may be your best option.
    • Yet another option is to use an above ground open reservoir to hold the water that you have collected. A layer of concrete or densely packed gravel can prevent the water from absorbing into the ground. However, in areas that are especially dry, this method would likely result in the loss of all or most of the water through evaporation before it could be used. Additionally, because of town and city ordinances against open reservoirs (but that usually except chlorinated pools) such a reservoir is not really a valid option for anyone but those who live in rural regions.
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    Connect the storage unit to the conveyance system. Extend the pipes or channels to the barrels, cisterns, or reservoir that will be used. Remember that the best conveyance systems are powered by gravity. If the storage unit is above the level of the pipes or channel, it will have to be pumped into the barrels or tank. If you intend to use a gas or electric pump to do so, the savings that come with collecting free water will be diminished.
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    Develop a system for water retrieval. You must be able to draw water from the storage units whenever it is needed.
    • For those with above-ground barrels or tanks, the usual method is to elevate the storage units and place a release spigot near the bottom of the unit. Pressure from the water above the point of the spigot will push out the water below.
    • Below-ground tanks will require some form of pump. When selecting a pump, you must determine the quantity of pressure required to do the job. If, for example, you are trying to water your lawn you must calculate the quantity of pressure needed to push the water through the hose(s). Keep in mind as well that pressure can be lost due to friction, and long pipes or hoses serving as your water retrieval system can result in greatly diminished pressures.
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    Add filtration mechanisms (optional). Though the water that you collect from a rooftop or hillside should not be drank, it may still be a good idea to install filters of some sort. The pipe and storage tanks could fill or become clogged with dirt. Because some chemicals may be present in the rainwater in your area--and will only be concentrated in your storage tanks--you may also want to partially purify the water before using it on your garden or lawn. Install these between the collection and conveyance sections if you are using pipes, or between the conveyance system and storage unit if you are using a channel. You could also filter the water as it leaves the storage unit to make sure that it is at its cleanest when you decide to use it.


  • If you don't want to invest in a pump, you can siphon water out and still run it out of a hose. This is cheaper and will not require electricity, but a little less convenient.


  • Rainwater should not be used for drinking except in emergencies. The best water source for drinking is one that has undergone a filtration process called reverse osmosis.
  • Collecting Rainwater is restricted in many parts of the U.S. It is legal only under very specific circumstances in the state of Colorado, and it is illegal altogether in certain other states.

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Categories: Water Conservation Solutions