Every winter, the Pacific Northwest earns its tongue-in-cheek nickname, the Pacific North-wet. From October to April, we have more water than we know what to do with so most of us let it wash down the drain, literally! Come summer when our skies clear and the rain stops, we buy it back to water our thirsty gardens. How silly is that? Rather than waste the abundance of water delivered in the wet seasons, we can save it for the hot and dry summers when our communities need it most.
What is rainwater harvesting?
Rainwater harvesting is the collection of rainwater from a structure, or other impervious surfaceSurfaces that water can’t pass through., to store it for later use. Typically, this involves harvesting the rain from a roof. Gutters capture rain then channel the water into one or more downspouts that flow into a storage vessel. Rainwater harvesting can be as simple as collecting rain in a barrel or as elaborate as a system of large cisterns that can support an entire community.
Collected rainwater can be used both indoors and outdoors. It can be used to water gardens, wash cars, flush toilets, and put out wildfires. Some systems can even filter and purify the water making it suitable for drinking.
Harvesting rainwater, when done correctly, has many benefits.
Collecting rainwater helps reduce the impact of runoffThe flow of excess water running over a surface.. When delivered in large quantities, stormwaterA large amount of precipitation resulting from a storm. can overwhelm nearby rivers, creeks, and streams. Without being about to soak into the ground gradually, excessive rainwater erodes streambanks, floods neighborhoods, and transports pollution. Rainwater harvesting lessens the force stormwater has on your property and in your neighborhood by reducing the volume and intensity of water flowing across impervious surfaces.
Plants and beneficial insects flourish with irrigation from collected rainwater. Most city water has low levels of chlorine, an important additive that keeps water safe for drinking. While this chlorine won’t kill plants, it can harm the beneficial microbes that live in the soil.
Climate change is making it more important than ever to conserve water. Our region expects to encounter a shortage of water as we experience longer, more intense periods of drought. As water availability becomes more uncertain, it will also become more expensive. By collecting rainwater now, you can get in the practice of planning for extended droughts while also saving money on your future monthly water bill.
How much does it cost to harvest rainwater?
There are many important factors to consider when researching rainwater harvesting systems:
- Design elements to ensure that water stays clean from algae and bugs
- Adequate sealing to prevent leaking
- Non-destructive installation methods to protect existing gutters and downspouts
- Additional features to control flow and connect to city sewer systems
Installing a home rainwater harvesting system typically costs between $8,000 and $10,000 and should be installed by professional contractor. Prices vary depending on the type and size of your harvesting system and how you intended to use the water.
Depending on where you live, a rainwater harvesting system can be built right into your existing water supply. This means that your municipality’s water system can be used as a back-up once your collection has gone dry.
How much rainwater can you collect?
How much water you can collect depends on the size of your catchment area, the type of material it is made of, and where you live. Use the calculator below to get a rough estimate how much rainwater you could collect each year.
Despite widespread belief, it is legal to collect rainwater in Oregon.
If you’ve ever talked about collecting and using rainwater in Oregon, someone has probably told you it’s illegal.
That is incorrect. It’s perfectly legal to harvest rainwater in Oregon, providing you catch the rainwater off an artificial, impervious surface, like a roof or parking lot. You can’t build a dam or dig a big hole to capture rainwater and store it.
Generally, permits are not required for rainwater harvesting systems that are used for outside irrigation. Some systems, especially larger systems or those intended for indoor water use, may require permits. Check with your local city or municipality regarding restrictions, permits, and rebates.
Which rainwater harvesting system is the right fit for you?
When it comes to rainwater harvesting, the possibilities are endless. Explore a few different options to see which may be the right fit for your yard or community space:
Tualatin SWCD is helping Washington County residents harvest rainwater.
Tualatin SWCD can help you design a rainwater harvesting system that works for you. We offer free consultations to discuss your options and have programs that can help pay for installation in urban areas of Washington County. Read how we worked with one resident in Aloha to install a rainwater cistern on his property. Contact us if you are interested in installing a rainwater harvesting system.