Rainwater Collection and Storage
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Why collect rainwater?
Rainwater collection - also known as rainwater harvesting - is the collection of rainwater that would primarily be run-off and make it's way into sewers and/or creek beds as overflow.
Benefits
Facts
On average, a person in the US requires a minimum of 13 gallons of water per day to meet basic human needs. Many countries in arid regions live off much less. However, Americans use at least 50 gallons per day on average to meet our current lifestyle. If you include irrigation water in this calculation, it quickly doubles to over 100 gallons of water per day. Yet, globally water supplies are increasingly coming under severe stress.
In addition, despite municipal diligence, testing is indicating more and more pesticides and herbicides are showing up in the water supply. In the US, simple, every day products, like well-known, brand name weed killers have been found in the water as well as 30 different pharmaceuticals and related chemicals in surface water samples (Ternes, 1998). These chemicals enter our drinking water supplies when they are flushed down the toilet and they are compounding in our water systems because they never get filtered out!
Ask yourself, "What will I do when- not if - the tap goes dry?" Being left without water from a municipal grid is a serious situation that borders on crisis - and yet worldwide it's becoming more and more of a possibility - if not a reality. The problems are often even worse for those on independent wells. Unless you live in a place that receives a huge amount of rainfall, many people are finding their wells are going dry earlier and earlier in their respective dry seasons. With rain water collection, it's easy to measure your water level and monitor your consumption accordingly.
Where is the nearest fresh water source you could use for drinking water? A pond at the local golf course? Who knows if it's safe to drink? Would you buy all of your water in bottles from the grocery store? That could get expensive. Water delivery? Also gets expensive. By collecting the rain, you control your water source and, once your system is in place, it costs you nothing.
Independent, sustainable water supplies utilizing rainwater harvesting are the way of the future. They are safe, easy to maintain and it's the smart thing to do. Rainwater is free of chlorine and pollutants commonly found in municipal water grids.
Benefits
- By capturing this water and filtering it, you can provide a clean and independent water source for your family in an eco-friendly manner. Properly managed, you may be able to go off all other water sources.
- If it's your only source of water, there is no monthly utility bill to pay or well to maintain and you can also receive a tax credit in many areas. Check with you local county authority for details.
- If you are making your own cheese, beer, or any other recipe that requires non-chlorinated water, you won't need to buy bottled water at the store.
- Rainwater collection offers a storm management tool. Capturing rainwater before it becomes storm water not only decreases the amount of stormwater that needs to be treated, it also decreases the amount of water that quickly runs off the land into local streams, often scouring them in the process. Permaculture practices offer a nice complement to rainwater collection to help keep water beneifically on your property and minimize erosion.
Facts
On average, a person in the US requires a minimum of 13 gallons of water per day to meet basic human needs. Many countries in arid regions live off much less. However, Americans use at least 50 gallons per day on average to meet our current lifestyle. If you include irrigation water in this calculation, it quickly doubles to over 100 gallons of water per day. Yet, globally water supplies are increasingly coming under severe stress.
In addition, despite municipal diligence, testing is indicating more and more pesticides and herbicides are showing up in the water supply. In the US, simple, every day products, like well-known, brand name weed killers have been found in the water as well as 30 different pharmaceuticals and related chemicals in surface water samples (Ternes, 1998). These chemicals enter our drinking water supplies when they are flushed down the toilet and they are compounding in our water systems because they never get filtered out!
Ask yourself, "What will I do when- not if - the tap goes dry?" Being left without water from a municipal grid is a serious situation that borders on crisis - and yet worldwide it's becoming more and more of a possibility - if not a reality. The problems are often even worse for those on independent wells. Unless you live in a place that receives a huge amount of rainfall, many people are finding their wells are going dry earlier and earlier in their respective dry seasons. With rain water collection, it's easy to measure your water level and monitor your consumption accordingly.
Where is the nearest fresh water source you could use for drinking water? A pond at the local golf course? Who knows if it's safe to drink? Would you buy all of your water in bottles from the grocery store? That could get expensive. Water delivery? Also gets expensive. By collecting the rain, you control your water source and, once your system is in place, it costs you nothing.
Independent, sustainable water supplies utilizing rainwater harvesting are the way of the future. They are safe, easy to maintain and it's the smart thing to do. Rainwater is free of chlorine and pollutants commonly found in municipal water grids.
Required equipment
1. Surface areas to collect from. This can be any kind of surface where water collects such as roofs and even pool covers.
2. A system such as gutters to gather and transport the water from the collection surfaces to the storage facillities- usually a tank.
3. A "first wash" method which can be a roof washer, filter, or eliminator
3. Holding tanks
4. A method to filter the water so it can be used for its targeted purpose.
2. A system such as gutters to gather and transport the water from the collection surfaces to the storage facillities- usually a tank.
3. A "first wash" method which can be a roof washer, filter, or eliminator
3. Holding tanks
4. A method to filter the water so it can be used for its targeted purpose.
Remember, maintenance is critical for a successful rainwater collection system
How to plan for rain water collection1. Surface areaBe creative when thinking about your surface areas. Metal roofs work well. You can collect water off of any roof, but if you are going to use it for drinking water, looking into the materials used to compose your roof. Also, think about areas such as pool covers or any other flat surface where water will pool and can be deposited into a holding tank. You may need to purchase a pump to collect the water from the surface and move it to anther areas for collection.
How much collection area is needed: In a geographic area of with an average rainfall of approximately 32 inches per year it is recommended to have at least 1000-1200 square feet of collection surface per person. Therefore, two people living in this area should have 15,000 gallons of storage and 2400 square feet of collection surface. |
 This structure uses a 45 degree downspout which is more congruent with the design of the house, but has a tendency to lose more water due to back pressure during heavy rainfall. |
2. Moving the water
The water will need to be moved from the collection area to the holding tanks. Gutters and pipes are the most typical way of doing this, but it can also be done by hoses. Consider the width of the gutter, pipe or hose you will need. This is determined by how much water you typically receive in a one hour period. In areas where consistent, soft showers are the norm, a smaller width or diameter or the transportation method is acceptable. If your area experiences heavy downpours, you'll want at least 5 to 6 inch gutters (or the wider if possible). The same is true with the pipes that will carry the water to the holding tanks.
Be sure to check your transportation system on a regular basis. Gutters and pipes should be kept clear of debris. Check your down spouts to ensure all the connections are solid and leakage does not occur.
The angles of your down spouts are important. Many people like to make the elbows of their gutters and down spouts to follow the lines of their house as closely as possible so the water transportation system does not interfere with the lines of the building's architecture. However, if you are prone to heavy rains, a downspout with a more gradual angle will capture more water.
Be sure to check your transportation system on a regular basis. Gutters and pipes should be kept clear of debris. Check your down spouts to ensure all the connections are solid and leakage does not occur.
The angles of your down spouts are important. Many people like to make the elbows of their gutters and down spouts to follow the lines of their house as closely as possible so the water transportation system does not interfere with the lines of the building's architecture. However, if you are prone to heavy rains, a downspout with a more gradual angle will capture more water.
 This structure makes use of a more slope versus the one above. The downspout is more visible, but the water encounters less back pressure when moving downwards. |
 Functionality was the key consideration when using this barn's roof area as a collection surface. Screens were place over the gutters and mouths of the down pipes to filter debris before it enters the roof washer area. |
3. First wash method
Roofs and other collection areas quickly accumulate dust, dirt, leaves, bird droppings and other debris that you do not want in your water. This problem is solved by having a device or method that will remove sediment and debris that has collected onto your collection areas. When enough rain has fallen that some run-off begins to occur, the roof washer or eliminator will divert this early water into a separate holding tank that can be used for purposes other than drinking water such as filling ponds or watering plants. It is important to locate this device in an easily accessible area so you can regularly check on the system. A malfunctioing system can cause you to lose a significant amount of the harvestable rainwater.
A roof washer should not stop the practice of physically cleaning the roof just before the rains are due to start. Rather, both methods combined should provide the best results in rainwater harvesting.
A roof washer should not stop the practice of physically cleaning the roof just before the rains are due to start. Rather, both methods combined should provide the best results in rainwater harvesting.
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Options:
1. Filter type A filter inside a fiberglass housing removes sediment up to 100 microns from rainwater before it enters the storage tank. It does not remove stains in the water caused by leaf tannins and pollen. It can be mounted at the same level or above the inlet of the storage tank, but always BELOW the lowest downspout (optimally, at least two feet lower). It must be drained and cleaned regularly to prevent the formation of algae in the translucent box. The filter can be pressure washed and makes an excellent choice when your collection area sits at the same level or higher than your storage tanks. 2. First flush capture Also known as an eliminator this is a type of roof washer that, instead of filtering rainwater, captures a metered wash -- the first, dirtiest flush -- before it can enter the storage tank. This system does require the dumping of the designated amount of captured water between rain events. However, this captured water, with its concentration of leaves and other organic debris, makes a great compost tea for your plants and can also be used in measure amounts for uses like ponds where the fish and aquatic plants will take delight with the nutrients being put into the water. 4. Collection and holding the water in tanksOnce the initial water is diverted the remaining water will be moved into the collection tanks. Tanks are available in many different sizes, from a few gallons to collect water for watering plants to 10s of thousands of gallons for serving household needs. As an example, in an area that receives approximately an average of 32 inches of rainfall per year, it is recommended to have at least 5000-7500 gallons per person in storage capacity.
Holding tanks are available in a wide variety of materials, surface options, and colors. How to select the right tank that best meets your requirements1. What is the targeted use of the collected water?
Dark colors will deter the growth of algae, while lighter colors such as white are likely to quickly incur algae growth, particularly in warm climates. 2. How much space is available for the tanks? Perhaps a small tank located adjacent to a shed, barn or garden is helpful for your daily chores and a 350 to 500 gallon tank will meet your needs for quite some time. For larger requirements, like household use, tanks of 7,500 gallons and upwards are the most useful. 3. Are their neighborhood or other restrictions that dictate how close the tanks can be located to building lines and how high they can be? Tanks are available in various profiles as well as capacities. In some areas, a low profile tank might be a more attractive option as it may be able to be camoflauged by trees or other landscaping materials. |
 First flush capture type of roof washer, also known as an Eliminator  Home made roof washer for livestock purposes made from PVC  Multiple tanks are used in this storage system used a "balanced" method. Alternatively, you can segregate the two tanks, using one for purchased water if needed and keeping one with rainwater. |
4. Construction materials
Fiber glass: If made of USDA approved food-grade polyester resin interior and gel-coated exterior, these are generally approved for potable for rainwater usage. Rainwater, due to its low pH, can't be stored in just an container. Check with suppliers for details.
Metal: Not recommended for human consumption and galvanized steel is not recommended for animals, but can be used for gardens and household plants. If the metal is lined with a resin material, these may be suitable for animal use as well.
Plastic: these are the typical rain barrels and smaller barrels you see at garden, home improvement and farm supply stores. These are suitable for plants or animal usage, but will not produce potable water. Custom tanks: these include water walls and hybrid tanks where conventional solutions may not be an option. They are offered by many suppliers, so check with them on options.
Fiber glass: If made of USDA approved food-grade polyester resin interior and gel-coated exterior, these are generally approved for potable for rainwater usage. Rainwater, due to its low pH, can't be stored in just an container. Check with suppliers for details.
Metal: Not recommended for human consumption and galvanized steel is not recommended for animals, but can be used for gardens and household plants. If the metal is lined with a resin material, these may be suitable for animal use as well.
Plastic: these are the typical rain barrels and smaller barrels you see at garden, home improvement and farm supply stores. These are suitable for plants or animal usage, but will not produce potable water. Custom tanks: these include water walls and hybrid tanks where conventional solutions may not be an option. They are offered by many suppliers, so check with them on options.
5. Tank site selection and preparation
1. A flat location: When using traditional tanks and barrels, select a site that is as flat as possible and has a minimal number of trees or shrubs that will have to be removed. It is recommended to make the area as evenly flat as possible.
2. Surrounding plants, utilities, other structures and property restrictions. Think about power lines and poles. If you are bringing in a larger tank that will have to be delivered and set into place by a crane, these can sometimes present problems. Be sure to get any required permits ahead of time.Remove any trees, shrubs, etc that will touch the perimeter of the tank upon installation. If you have nearby trees that may send their roots into the tank in search of water those will be need to be removed.
3. A pad. Fiberglass and metal tanks need to sit on a pad made of sand that is 6 to 8 inches deep. The pad for the tank doesn't have to be fancy, but it does need to be level and absolutely free of any rocks or roots that could crack the bottom of the tank as it grows heavy with water. Although a 10,000-gallon tank full of water weighs about 40 tons, a concrete pad is overkill.
2. Surrounding plants, utilities, other structures and property restrictions. Think about power lines and poles. If you are bringing in a larger tank that will have to be delivered and set into place by a crane, these can sometimes present problems. Be sure to get any required permits ahead of time.Remove any trees, shrubs, etc that will touch the perimeter of the tank upon installation. If you have nearby trees that may send their roots into the tank in search of water those will be need to be removed.
3. A pad. Fiberglass and metal tanks need to sit on a pad made of sand that is 6 to 8 inches deep. The pad for the tank doesn't have to be fancy, but it does need to be level and absolutely free of any rocks or roots that could crack the bottom of the tank as it grows heavy with water. Although a 10,000-gallon tank full of water weighs about 40 tons, a concrete pad is overkill.
6. Pumps and final filteringPumps:
For many residential situations, a Grundfos MQ is recommended. The Grundfos doesn't require a separate pressure tank because it is built in and is rated specifically for use with rainwater. Filtration and disinfecting specifications:
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7. Low point drains
One of the necessary items you will need is a low point drain. Locate your drain preferably at the lowest spot in your piping.
A low point drain:
A low point drain:
- Prevents mosquito infestation during long periods without rain
- Permits you to drain the line to prevent the line from freezing
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