What can rainwater be used for?

Collected rainwater has the potential to meet any indoor or outdoor demand. In fact, there are many examples, in the Pacific Northwest and elsewhere, of households that use rainwater as their sole water source for all indoor and outdoor, potable and non-potable applications. In practice, the use of rainwater for certain purposes can be subject to regulation by municipal and regional authorities. Tempest is keen to work on your behalf to address any barriers that may exist. We can also assess your site's potential for collection and determine the feasibility of creating adequate supply for your intended use.


Relatively inexpensive treatment systems can be installed to bring rainwater to acceptable potable standards. It can then be used in any household application. Regardless of your reason for installing a rainwater harvesting system, Tempest will only use conveyance and storage components that are certified for potable use. This will make it easier to upgrade to a potable system later if required. To ensure you have a safe water supply, Tempest will analyze any existing system components (eg. roofs and gutters) for suitability, perform water testing, install appropriate water treatment and can complete required maintenance to ensure your drinking water remains pure and clean.


The simplest rainwater harvesting systems are non-potable and require only basic gravity-powered filtration. In all systems, we need to make sure that the collection and conveyance components (roofs, gutters, downspouts and other piping) are kept as clean as possible to ensure water quality, but there will always be dust and debris that will come into contact with rainwater before it makes its way into your storage and distribution systems. However, even without post-storage filtration and disinfection to render the water potable, rainwater can be used for a variety of indoor and outdoor applications.


Irrigation is a fantastic use for rainwater that is free of chemical disinfectants. Using rainwater in your landscape can be as simple as relying on gravity to fill up a watering can or low-pressure drip irrigation system. Other applications will require pumps to provide the right amount of pressure needed to move the water through distribution lines and irrigation systems to wherever you may need it on your site.

Indoor uses

Rainwater can be used indoors for certain non-potable purposes, most commonly for toilet flushing but potentially for other applications as well. Many people are surprised to learn that more than a quarter of the average household's water consumption is through their toilets. In commercial settings, this proportion is often much higher.


Livestock require plenty of water both to drink and for cleaning of the animals themselves and the facilities that support them. Why not collect rainwater for this purpose?

Other landscape uses

Rainwater is perfect for filling swimming pools, hot tubs and to replenish ponds and other landscape features that lose water through evaporation.

outdoor power and vehicle washing

Many people use rainwater to supply their power washers or clean their vehicles rather than clean, treated drinking water. Depending on your usage patterns, this can save a lot of water!

emergency purposes

For many remote properties, fire protection is a serious concern, and your rainwater reservoir can supply you or the local fire department with an available on-site water source. In some cases, insurance companies will recognize the additional security this provides with reduced premiums. Your reservoir can also provide for your needs if there is an unexpected disruption of municipal or other water sources in the event of an earthquake or other natural disaster.