Rainwater Harvesting and Water Catchment Systems

rainwater harvesting image

What is rainwater harvesting?

It simple is catching water in a containment system of some sorts to use for another purpose.
Who would harvest rainwater?
People have been harvesting rainwater since nearly the beginning of time; this is definitely not a new concept. There are records that indicate that back in the 3rd century B.C. in India people were actually punished for not participating in rainwater collecting. Can you imagine? Times sure have changed.
Today many people harvest rainwater for many reasons. The first reason is that certain areas are more prone to drought conditions. People find that through water collection they can use this water to protect their crops against the conditions. And with the ever changing weather conditions we’ve been having throughout the nation, we really never know how much rain we will get during growing season. By collecting rainwater, you can also help prevent flooding near your homes foundation when the rain does finally come and use it in a permaculture system.  
Besides using the water for growing, many people also use it for laundry, dishes and hygiene. According to rainharvesting.com, by using the water for these purposes you can reduce main water requirements of your home by up to 70%. And if you pay for your water usage, you would definitely benefit from having a 70% decrease in your water bill ! If your hot water system is supplied with rain water, that savings jumps up to 85% !
Speaking of numbers, did you know the average home uses 3 gallons of water for flushing the toilet, showering uses 2-2.5 per minute, Washing clothes uses 25-40 gallons a load depending on the type and year of the washer, dishwashers use 20 gallons per load, and to take a bath? That’s 36 gallons right there! That’s ALOT, of water usage!  
But can you drink it??  
By now you may be wondering if you can also drink rainwater. There are two main perspectives about that: yes and no. Many people feel that drinking rainwater is perfectly safe and argue that people in some countries do this daily so it must be perfectly safe. Then you have other people who would say that no, it is not safe to drink at all.  As far as this goes it is important to remember that rainwater can contain pollutants and organisms among other things, but there are actually ways to purify it for drinking.  But back to purification methods real quick, the first way you can purify rainwater is through using the boiling method for 10-15 minutes. This is a great method because it is fast and kills waterborne pathogens effectively.  
(photo credit: modernsurvivalblog.com)
You could also use chemicals to purify it like bleach for instance; just add 8 drops of liquid bleach to 1 gallon of rainwater. Make sure to wait 30 minutes, if you are in a situation where the water is near freezing you should wait an hour before drinking.  A third method to purify rainwater for drinking is through solar purification, also called solar pasteurization. Put the water into a clear zip lock bag and it on top of a flat piece of aluminum foil, shiny side up. Make sure to place it in direct sunlight and keep in there. The water needs to remain at 160 degrees for several hours. You can also use an empty water bottle for this.  
You could also make a filtration device, but remember filtration and disinfecting water are two different things entirely. Filtration only removes debris and parasites that may be living in the water. Disinfection kills harmful organisms and viruses that will make you sick. Therefore even if you filter the water, you still have to disinfect it before you can drink it.
 But back to our main subject….  
(photo credit: primedpreppers.com)


How to Harvest Rainwater?

There are two main ways to harvest rainwater. The first is by using a rainwater cistern. What this is, is typically an underground basin of water. A cistern is normally made of a concrete or masonry tank and our sealed to prevent contaminants, except what is already in the water it’s self already. These are mainly used for farms or homesteads, and ideal for those who wish to live self-sufficiently or even off the grid. Cisterns can also be built aboveground and be harnessed to pressurize your home’s waterlines.

The second way to harvest rainwater, which by the way has become more main stream, is by purchasing or making your own water catchment system. For a water catchment system to work, you need to consider four main elements: Area, slop, drain, and storage.
If making a water catchment system that is attached to your home, the area in this case is your roof. Your gutters serve as the slope as the water moves down these into the drain toward your storage or container. For these containers, many people use 15, 30, or 55 gallon drums, a 275 gallon water tanks, or a large rubber trash barrel with a lid. All of these containers are for non-potable water. If you are planning to collect rainwater for potable or drinking water for later purification, I would recommend finding a container that is made of food grade plastic. To build a system you can use your existing guttering to collect the water, and then direct the water into one of the chosen containers.

Make sure to use a screen to filter the water through to prevent debris from gathering into the container. If you are using more than one container, you can use PVC pipe and fittings to join the barrels to create a reserve. You would also attach a garden hose adapter so that you can you can screw in your garden hose to water your garden or fill smaller containers to purify to drink, if needed.
There are many different types of designs for building your own water catchment systems that you can find online, or if you are creative you can make your own design.


Before building your system, rain harvesting is actually considered illegal in some areas. If you happen to be a rebel and plan to make a system anyway, you can find a way around this by enclosing it or running your PVC into a shed or garage to collect the same way only out of the view of prying eyes.



  1. Yeah. I agree with what you say. Rainwater is a viable water resource now because of global warming, which has brought about increasingly erratic weather. Add the fact that traditional surface water have either dried up or have become less and less potable due to pollution, and people will be hard-pressed to find alternate sources. We should always look into other ways of procuring water, as well as conserving it. Anyway, thanks for sharing your thoughts on the matter.

    Bert Aguilar @ Rainfill Tanks