Rainwater Harvesting

We have covered the basics of water harvesting and the use of storage containers in complex water harvesting on these pages.  Most rainwater harvesting is for the purpose of watering grass, gardens and landscape plants.  Because of the pure nature of rainwater it can also collected, stored and used for potable water uses.  This means you can drink and bath in rainwater you harvested from your own roof.

When we begin any discussion about solar panels and getting off grid we first mention conservation.  We need to learn to get by with less power by changing our home and our habits.  The same thing is true of water harvesting.  Your first step to the successful use of harvested water will be learning to conserve it and use it wisely.

Conserving water is a big subject and will not be completely covered in the course of a couple of paragraphs.  Hopefully we will at least get you thinking in the right direction.  The use of low flow shower heads and dual flush toilets is a good start.  Turn the water off when brushing your teeth, run the dishwasher only when full and consider using gray water on your plants.  Outside landscaping should be considered also.  Ideally you should have only what you can water with the combination of harvested water and gray water.

When starting out with rainwater harvesting it is recommended you first take care of all of your non-potable uses first.  This is easier and less expensive.  This means you take care of the outdoor stuff, like gardens, trees and livestock.  If you still have harvested water left over, and the finances available, then it's time to consider using your harvesting system for indoor uses.

We mention finances because you need to be sure the water you bring into your home is clean, pure and ready for drinking.  This adds considerable expense to you harvesting system.  It is possible to get set up with a plastic cistern, a well pump, a roof washer and a UV sterilizer for around fifteen hundred dollars.  It is also possible to spend fifteen thousand or better on more sophisticated forms of storage and filtering.  You can start slow or jump in full bore, that part is up to you.

Determining your water use, after using water conservation methods, and see if it is possible to harvest enough rainwater to fill your needs.  The water harvested will depend on the size of your storage and the size of your collection area.  Obviously, one small roof top, even in a good rain, will not allow you to harvest a large amount of water.  Another consideration will be the yearly rainfall for your area.  To take care of all your needs it's good to be in an area with an annual rainfall of about twenty four inches.

Rainwater harvesting for potable use means you need to pay particular attention to your catchment system, usually a roof.  If you home roof is not suitable, either because of size or type, consider a "water barn".  This is roof built for the purpose of water harvesting.  There is no reason why the water barn cannot serve a dual purpose, like a shed, barn, loafing shed, hen house or you name it, but it does not have to.  It can just collect rainwater.

The best roof for collecting water from is uncoated stainless steel or factory enameled galvanized steel with a baked-enamel, lead free finish.  If you plan to use an existing metal roof it should be checked for any traces of lead.  Wood shakes, asphalt shingles and clay tiles are not recommended for catchments.  Ideally your roof should not be directly under large trees.  This causes less water to fall on the roof and the possibility of bird droppings.  If you use a fire place be aware of the possibilities of soot deposits on your roof.  These deposits could contain polynuclear aromatic hydrocarbons or other hazardous materials.

Washing the catchment roof in between rains is an important part of rainwater harvesting for potable uses.  Some systems have built in roof washing systems, or one can be home made out of PVC pipe.  Depending on the type of washer your system uses and depending on the amount of debris your roof might collect determines the amount of additional washing you might need to do.  You do want to make sure the money going into you containment tank is as clean as possible.

Water treatment is another additional element needed when harvesting water for potable uses.  Your system should start with a roof washing system and then a preliminary filter.  Your other treatment options include micro filtration, UV sterilization and ozonation.  A popular method of treatment uses  physical filters to remove particulates and a UV light chamber to kill bacteria and other organisms.  The least expensive form of water treatment is simply adding chlorine or bleach to the water.

Weather your rainwater harvesting amounts to a few buckets of water every time it rains or enough to take care all your needs for a month, get started.  It's very green and lots of fun.