How to Store and Use Rainwater

May 11, 2016

When it rains it pours. Why not capture it?

After an unseasonably dry summer in the Northwest last year, we breathed a sign of relief when the rains returned to rejuvenate the earth and our gardens. The good news is that according to the Cascade Water Alliance, the reservoirs are back up to normal! If we learned one thing, it was to not take water for granted. As landscape designers and gardeners, we can make a big impact on our environment by creating more drought tolerant gardens and using water more efficiently in the garden.

One way to do so is by storing and using rainfall that would otherwise end up in the sewer system. Rainwater harvesting is a great way to lessen the impact on the environment while saving money on your water bill at the same time!

Rain Storage Systems

Harvesting systems can be purchased from a number of garden centers and home improvement stores. Rain barrels are a very simple way to capture rain from your roof,  are very user-friendly and are also reasonably priced so that you can quickly see a return on your investment.

With easy-to-install kits, it’s simple to get your own basic water harvesting system established. Installing a first flush diverter also helps to reduce contaminants from your roof to improve the water quality. Barrels range in size, with the most common types having the capacity for 55 gallons.


Photo Credit:

What happens when the rain barrel gets full?

You may be surprised how quickly one rainfall can fill up a rain barrel, which is why you may want to have several if you have the space. The barrel should have an overflow pipe that directs extra water, ideally, into a rain garden or swale (or dry stream bed).

Diverting extra water to a rain garden or swale slows it down, keeps it out of the storm drains, and allows the soil to filter it naturally. It also adds beauty to your garden! In the photo below, you’ll see a dry stream bed that serves as a storm water collector during rainy periods.

Rain Garden Dry Creek Bed by Sublime Garden Design_800x570

Photo Credit: Heidi Skievaski

If you are interested in storing water on a larger scale, then you should consider installing an underground cistern. With the ability to hold several thousand gallons, you’ll can use captured water for much more than lawn and garden care.

With the right system in place, you can use your collected grey water to run your washing machine and to meet your water needs in your home’s bathrooms. With a filtration system installed, you can also use the water for washing dishes, running your dishwasher, and to meet a significant amount of your water needs in and around your home.

Be aware, however, that installing an underground cistern is a significant investment. If you just want to get your feet wet, so to speak, start with one of the simple rain barrel kits. If you start to notice a positive impact on your utility bills, or if you just want to do more to save water, you can then determine if you want to take water harvesting to the next level.

Safety and precautions

It may go without saying, but do not drink water captured from a rain barrel. In most cases you also do not want to use water captured from your roof to water edibles. Do not use water from your roof to water plants if it has been treated with any chemicals, including moss killers, or if you have a copper roof or gutters. For safety reasons make sure your barrel is screened and always covered to prevent children and small animals from falling in and drowning, and to prevent mosquitoes from multiplying.

Make sure that your rain barrel was intended to be used as such– do not use a garbage can or other container that may not be sturdy enough to hold large amounts for water.  Make sure that your barrel is installed on a level and stable surface and if you live in an area that freezes often in the winter, you may want to disconnect your rain barrel to prevent it from cracking due to multiple freeze and thaws.

One last word of advice

Before you spring into action, be sure to check your local municipal codes. Some municipalities discourage rainwater harvesting by specifying that you are only allowed to collect a certain amount or ban it all together, while other municipalities encourage it and will provide tax credits. Either way, it’s wise to know what you’re getting into before diving in head first.

Happy water-wise gardening!


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