On April 7, 2017, California Governor Jerry Brown declared the state’s historic drought over. But that doesn’t mean it’s time to return to the freewheeling days of wide-open faucets. If you’re looking for a way to stay green while keeping your lawn from turning brown, the answer may be home rainwater collecting.
In rural areas, rainwater seeps into the ground and replenishes the aquifer, an underground layer of water-bearing rock, such as gravel or silt, that stores groundwater. In suburban or urban areas, much of the rain that falls is swept into the storm drain system.
A rainwater collection system allows you to capture this water on your property and helps you minimize the usage of water from your utility. A typical system consists of a rain barrel installed at the bottom of gutter downspouts to capture the rainwater that falls on your roof. Water enters the barrel through a mesh filter that keeps out leaves, twigs, and other debris. The filter also helps to prevent mosquito breeding and keeps other pests out of the barrel. The barrel may also have a spigot near the bottom that you can connect to a hose to water your plants or connect to an irrigation system.
While it is illegal to dam or divert natural water sources such as rivers or lakes that flow through or are adjacent to your property, collecting water that falls on your property in the form of rain is legal in California. Just one inch of rain, collected from a 1000 square foot roof, is equivalent to 620 gallons of water, so the water savings add up fast.
If you are considering installing a rainwater collection system at your home, there is a good chance that your local water district has resources available on their website to guide you through the process of determining what system is right for you. Some may even offer materials like rain barrels at no or low cost.
Ready to have a go at rainwater collecting? Consider the following do’s and don’ts:
DO use rooftop water only. Although harvesting runoff from parking lots, patios, and walkways is technically possible, it is more difficult since a subterranean cistern or a pump is usually needed to move the water into an above-ground rain barrel or cistern. Also, there are typically greater levels of debris and contaminants that must be filtered out of the runoff before it enters the storage system.
DO consider your roof material. Chemicals from asphalt or wooden shingles can leach into the water. Roofs made from cement, clay, or metal surfaces are better for harvesting.
DO use a first-flush diverter to remove the first water that enters the system as this water will have the highest concentration of leaves, twigs, animal waste, sediment, and other contaminants. A first-flush diverter will direct the first few gallons of runoff from the roof away from the rain barrel.
DO use a rain barrel that is opaque or shielded from sunlight to slow the growth of algae inside the barrel.
DON’T drink the water or use it on fruit and vegetable plants. Without advanced filtration, rainwater is non-potable. Water harvested from rooftops and gutters may contain harmful bacteria, parasites, animal waste, or chemicals that could cause make you sick if ingested.
DON’T connect the system to a potable water source. Rainwater can contaminate potable water sources. If you intend to connect your rainwater collection system into your yard’s existing irrigation system, make sure you have the correct permits from your water utility and the proper backflow prevention device to avoid contamination.
DON’T introduce greywater into your system. Wastewater from your sink, washing machine and dishwasher may contain harmful bacteria that can flourish in your collection system.
DON’T forget to maintain your system. Clean the inside of your rain barrel of algae and debris at the beginning and end of each rainy season. Inspect gutters to make sure debris is not entering the collection system, and make sure screens are not damaged to restrict mosquito breeding.
Lastly, DON’T do it for the money! Water from municipal utilities is relatively inexpensive; in some areas of the state, water costs less than one cent per gallon. Even the most basic collection systems won’t make an impact on the money in your wallet, but when it comes to thinking and acting green, every little bit helps.
Before hiring a contractor to perform installation of your rainwater collection system, rain gutters, or roofing work, make sure they are properly licensed by the Contractors State License Board. And if your rainwater collection system includes landscaping elements, consider working with a landscape architect licensed by the Landscape Architects Technical Committee.