Tag Archives: non potable

What is the Most Common Use of Collected Rainwater?

Do you know that the most common use of collected rainwater is not for drinking? Here’s a prior post, which helps answer this question – and explains why non-potable use of rainwater is so popular – and sustainable.

The most common use of rainwater collection is for non-potable use. Irrigation, water features, wash down, toilet, and laundry are all non-potable uses that can have a positive effect on water conservation. A properly designed and installed rainwater collection system will provide enough water to support these desired uses with less impact on our water supply.

Rainwater is essentially free of pollution, so it can be stored without much more than screening. Storage can be underground, above ground, metal, plastic, or fiberglass. If irrigation is the desired use, keep in mind that approximately .623 gallons per sq ft of planting, per week is required for the healthy growth of plants, therefore storage volumes can be a concern in design due to space and costs. Conveyance can be gravity if there is enough head. Head is .4 lbs per foot of elevation. A pressure pump might be necessary to achieve the desired pressure needed. Sediment filtration for a simple irrigation system should be all that is needed to ensure emitters and soaker hoses perform as expected.

Water features such as fountains can recirculate the water being used, so very little storage would be required. Sediment and carbon filtration would be needed to keep pumps and nozzles working properly. A carbon filter would be helpful to keep odor to a minimum.

Wash down facilities can use rainwater collection and save money on their water bills by using rainwater collection as the rinse water. With enough storage, a large fleet can be washed with recycled wash water and rinsed with collected rainwater. Again, sediment and carbon filtration would be the only filtration needed. Wash down of equipment, whether construction or farming, can benefit from rainwater collection.

Toilet and laundry facilities for residential and commercial applications are becoming more popular with new construction. Rather than infiltration, which is mandated, why not use that water. Simple pumping and filtration of stored water is all the treatment needed. A return on investment can be achieved within a few years.

There are a wide range of uses for rainwater collection. With a little bit of imagination, you might come up with a use for rainwater collection that could save you money.

So, the next time you think collecting rainwater for drinking purposes is most common, think again – there are many more uses that are beneficial and sustainable.

Sustainability Key Rainwater Harvesting Benefit

RWC Washington State

Colorado needs to look no further than Seattle and Washington State for the sustainability benefits of Rainwater harvesting.

The Colorado rainwater harvesting narrative shows that as time marches forward, some laws that were passed almost one hundred years ago should be reconsidered because they are just no longer practical. Sustainability wasn’t a factor back then, but it sure needs to be part of the equation now.

In October 2009—after years of argument—the state of Washington officially declared that people could collect and store rainwater captured from a rooftop or other “guzzler” system without a water right, as long as it is used on site and essentially isn’t hurting anybody else. San Juan County was the only one that allowed rainwater collection and potable use for single family residence as an exemption to the water rights issue before the 2009 decision.

Since then, King County recognized the benefits of rainwater collection in January 2011 for household usage, with support from State Department of Agriculture. So now, King County Department of Health not only allows, but encourages rainwater collection.

Commercial, private, and communities all are finding benefits to rainwater collection and the positive effects on the environment of the Pacific Northwest and our water supplies. The Washington State Department of Ecology continues to support rainwater collection and studies the effects of in stream flow rates (Skagit) and salmon habitat.

All Washington State counties allow for rooftop collection for non-potable use, with some allowing for potable use. Non-potable use includes irrigation, toilet facility, laundry, wash down and others that are not intended for consumption or bathing. Commercial applications are directing roof runoff to irrigation and toilet facilities, rather than having this runoff enter our bodies of water with pollutants picked up along the way. Households are not only using rainwater for non-potable use, but are having systems installed that treat and disinfect the rainwater to potable standards that are superior to city drinking water, thus conserving water by simply not allowing it to become runoff. Rural households are using rainwater collection that benefits aquifers by rainwater collection and household use, through infiltration after use. Communities are organizing communal gardening applying rainwater collection, removing the strain on small water systems, while promoting community evolvement and education.

We congratulate Colorado on its progress in exploring new (to them) sustainability methods. We welcome Colorado’s steps towards better understanding of the benefits that we in Washington State currently enjoy.

Seattle Households Benefit From Rainwater Collection Year-Round

seattle-skylineWith an average annual rainfall amount of 37.5″, the Seattle area is an ideal environment for rainwater collection, since Seattle area households see a moderate climate compared to other cities in the United States.  Summers are generally short and winters are fairly moderate.

Let’s take a look at an average 2,500 sq. ft. home in Seattle, which can easily sustain itself while using rainwater collection for whole household use.

Autumn rainfall averages around 11.55″, filling tanks from the past summer’s use quickly with 17,911 gallons of water available for collection. Winter averages are around 14.42″ or the equivalent of 22,459 gallons available to keep tanks full. Spring continues with 13,036 gallons from an average of 8.37″, allowing levels to remain high. Even summer at an average of 3.15″ or 4.906 gallons available should keep tank levels from going dry to be filled again in the fall.

Seattle Precip 2015Depending on use, an average Seattle home can sustain itself on harvested rainwater without any change in lifestyle for the residents. The average demand from one occupant is 35 gallons per day or 1,050 per month – not including irrigation. Being connected to city water allows for a back up supply. Even with a small amount of storage, a supplemental system can conserve city water supplies and save money, by providing full usage during the wet periods. Future weather patterns predict wetter warmer winters and hotter, dryer summers. A look a last year’s averages on the above graph suggests this to be true. Rainwater collection is a perfect fit for Seattle residents whether non-potable or potable use is desired.