What are the components of a rainwater harvesting system?
Rainwater harvesting systems have 8 basic components that are vital to the functionality and reliability of the system. These components include:
- Catchment Area: This is the surface on which the rainwater falls.
- Conveyance: The gutters and downspouts connected to your house that brings the rainwater to the collection system.
- Vortex/First Flush Fine Filter: A fine mesh as small as 280 microns that filters out silt, sand and debris, preventing it from entering your storage tank. This type of filter also provides overflow protection for extreme rain events.
- Smoothing/Calming Inlet: Designed to distribute the harvested rainwater entering the tank evenly by dispersing the water in an upward and outward motion, the Smoothing Inlet is critical to ensure that the stored water is not disturbed when rainwater fills the tank. It also disperses the rainwater in a motion that facilitates the oxygenation of the entire tank.
- Storage Tank: This is the single largest investment for your rainwater harvesting system. Although there are a multitude of options for storing your collected rainwater, to get efficient use and sufficient storage, most homeowners will need more than what a 50 gallon rain barrel on the end of a downspout can provide.
- Floating Filter: Used to keep the suction filter clear of any contaminants on the surface or bottom of the tank, drawing the 'premium' water to the pump, extending the pump's life cycle.
- Pump: A submersible pump is used to draw the filtered rainwater from the tank for use. Depending on usage, you can install anywhere from a 1/2 horsepower pump up to a 1 horsepower pump.
- Overflow: The overflow a mechanism in a rainwater harvesting system that sheds excess water from extreme rain events and prevents backwash from entering the storage tank. In some cases it also skims the top of the stored water to clean the tank, and prevents rodents and animals from entering and contaminating the collected water.
What materials are best for collecting rainwater off a roof?
Provided the rainwater is for non-drinking water purposes, virtually any materials can be used in the collection system. If the rainwater will also be used to meet the potable water needs of a home's residents, it is important that the homeowner use care in selecting materials and coatings which will come into contact with the water as it is collected to prevent impurities as the rainwater travels through the collection system.
Examples can include:
- Asbestos roof materials used in older homes.
- Products such as asphalt shingles or lead materials in any form (lead flashing)
These types of materials can contribute particulate matter into the water, requiring additional filtration before the water reaches the storage tank or cistern.
If you do plan to use the collected rainwater for drinking, make sure the materials and/or coatings used in the construction of the storage reservoir have been tested to ensure they do not leach harmful contaminants into the water being stored.
In some situations, it may be necessary to install a home water treatment system to disinfect the water or to filter other impurities from the rainwater supply.
How much maintenance is required to maintain our system?
It is important to check your water harvesting system to make sure the water is moving where you want it to go. You can hire a trained professional to come and inspect your system annually, but here are some quick tips to keep your system operating efficiently.
- Keep gutters and downspouts free of debris
- Clean and maintain filters regularly, including drip filters
- Regularly flush debris from the bottom of storage containers
- Keep landscaped holding areas free of debris
- Control and prevent erosion
- Clean and repair
To keep your collection system free of debris, we recommend installing leaf screens on the entire length of the gutter, which will reduce the system's maintenance significantly.
How much water can I harvest, and how much storage do I need?
In general, 1 inch of rain on a 1000 square foot roof will produce approximately 623 gallons of harvestable rainwater. Storage depends on how much you plan to use, how much you plan to store, and what you want to use it for. For the maximum benefit of harvesting rainwater, it’s important to consider a long-term solution if you are considering harvesting rainwater- a 50 gallon barrel at the end of your downspout will be completely filled after one rain event.
We have made some basic calculations for Colorado based on the average monthly rainfall over the past 50 years- it should give you a good idea of the potential water you can harvest.
For storage, it all depends on how serious you are about harvesting rainwater. Flxx® Rainwater Harvesting and Equipment offers storage from ________ to ______ gallons for above ground tanks, and anywhere from 1000-10000 gallons for underground storage tanks. For an introductory product, we recommend something like this. For more information and to see our selections, feel free to contact us, or check out our products page.
What happens when my tank is full of water?
When your tank is filled completely with harvested rainwater, an installed device (conveniently called overflow, or overflow outlet) will divert the excess rainwater from your tank to wherever you designate.
Are pumps required to collect rainwater?
Pumps, just like filters, are not required to collect rainwater, but to effectively use rainwater, especially from an underground storage tank, a pump is necessary, if not required. If you have a system professionally designed or engineered, a pump will most likely be included in this design. If you would like to order a pump, we offer several different models here.
What about mosquitoes, rodents and other pests?
This is a legitimate concern, since these insects, rodents and other animals can potentially contaminate your water supply. There are several different ways to prevent this type of contamination- most of which is included with the tank or system that you order.
Pest Control of Rainwater Collection Systems
Mosquitoes, insects and other pests (such as birds, frogs, snakes) are undesirable elements to have in a rainwater harvesting system and must be kept out of all pipe systems that lead to the water storage vessel and the vessel itself.
Mosquitoes are known to be responsible for the spread of many diseases. Mosquitoes breed in water and all breeding habitats must be eliminated.
Mosquitoes can breed in almost any standing water around the home. Ensure containers holding water around your home are regularly changed or emptied weekly.
FRH recommends all rainwater collection systems be equipped with a First Flush Water Diverter, which is a simple accessory that diverts the first "flush" of rainwater most likely to carry contaminants and mosquito larvae from the roof. Other debris and insect prevention attachments such as Leaf Eater downspout filters also help minimize mosquito breeding areas.
Will my tank freeze in wintertime?
Although most above-ground tanks are designed not to freeze, the cold temperatures of the Rocky Mountains have proven manufacturers wrong before. Some hardware must be winterized to protect it from future leaks, but if freezing is a concern, we recommend considering an underground storage tank- the upfront cost might be slightly higher, but replacing a $300 rain barrel costs you $600.
How much does a system cost?
Pricing depends on the level of involvement and commitment you have to rainwater harvesting. Most of the pricing for our tanks is included on our products page. For more information, please contact us.