Category Archives: Rainwater Catchment

Commercial Rainwater Harvesting, Rainwater Catchment

How Rainwater Collection Protects Water Supplies

Federal Way Washdown_RainBankLLC_webCan Rainwater Collection Protect Water Supplies?

As mentioned in Ken Blair’s previous article, rainwater collection for residential and commercial construction helps protect our water supplies by using rainwater for irrigation, toilet facility, and other uses.

For example, the city of Federal Way, WA uses a rainwater collection system for its school maintenance facility. It collects rainwater for washing  its school bus fleet, and during the summer, the collected water is used for irrigation.

In Harvesting Nature’s Supply, ARCSA (American Rainwater Catchment Systems Association) board member, Neal Shapiro writes about a city library using rainwater collection for toilet flushing, Santa Monica’s first municipal building to implement rooftop rainwater harvesting for indoor use.

Shapiro, watershed management program coordinator for the Office of Sustainability and the Environment for the city of Santa Monica, CA, goes on to document the library’s rainwater harvesting system, showing  how rainwater can be collected on site for non-potable use in a commercial setting. This approach promotes the use of “local water resources and local self-sufficiency; reduces dependence on imported potable water, which benefits distant watersheds by keeping more water there; and reduces negative impacts from stormwater, which carries numerous pollutants to Santa Monica Bay”.

To read the full article, published on eStormwater.com, please click here.

Rainwater Catchment, Technical Information

Considerations for Water Treatment

FiltrationRainBank Rainwater Systems designs and installs custom treatment systems to meet customers’ specific needs.

Harmful bacteria, pathogens, and cysts removal is a must in a potable rainwater collection disinfection train. This is typically achieved with a class “A” UV light. Flow rates are calculated to achieve the correct amount of contact time with the UV spectrum for proper disinfection. The correct class of UV for a specific application is required. A class “A” UV must be used for water that is not deemed safe to drink. A class “B” is only used for water that has already been safe to drink.

But there are other considerations for water treatment. The raw water must be relatively free of sediments, turbidity, organics and inorganics before entering the UV chamber. The UV spectrum will not be able to penetrate the water column effectively otherwise. Special consideration of environmental constituents should also be addressed for proper treatment.

Environmental concerns can include location of collection area. Where is the house located?  Possible hydrocarbons Skagit_Filtrationfrom a nearby freeway would be a concern. Pesticide use from farming or city landscaping maintenance should be considered. Roof material and manufacturing process could pose a health threat and should be addressed – all of which can be corrected with proper filtration, whether it is accomplished with canister elements or back flush devices.

Rainwater is typically acidic, approximately 5.5 to 6.0 ph; nominal being 7.0 ph. The lower ph levels, while not considered harmful to humans, can have a negative effect on plumbing and fixtures. A more nominal ph level can be achieved with proper treatment.

Rainwater is relatively clean to begin with; much more than surface water. It is what it comes in contact with that can change its purity. Proper design and installation of a filtration and disinfection only comes from using the “right tools for the job”.

Rainwater Catchment, Sustainability

Should I Collect Rainwater From My Roof ?

rain-432770_1280There are many good reasons for collecting rainwater from your roof. By doing so, you would be helping to protect our rivers, streams, lakes, sounds, bays, and oceans from pollutants entering these bodies of water through stormwater runoff.

A combined sewer is a type of sewer system that collects sewage and surface runoff in a single pipe system. Combined sewers can cause serious water pollution problems due to combined sewer overflows, which are caused by large variations in flow between dry and wet weather. This type of sewer design is no longer used in building new communities (because modern design separates sanitary sewers from runoff), but many older cities continue to operate combined sewers.

By reducing runoff from our roofs, less water is entering the combined sewer system, reducing amounts of discharge into our bodies of water.

Collecting rainwater from our roofs reduces demand on our centralized water systems.

The overwhelming majority of the water used in the U.S. comes from freshwater supplies of surface and groundwater. Water extracted for public systems is treated to potable standards as defined by the Safe Drinking Water Act. Access to high quality water has greatly benefited public health, but it has also resulted in our current system which utilizes potable water for virtually every end use, even when lesser quality water would be sufficient. In addition to conservation methods, using alternative sources of water will be necessary for more efficient use of water resources.

Rainwater collection reduces electrical usage.

According to the EPA’S Rainwater Harvesting Policies, Municipal Handbook, the connection between water and energy is often overlooked, but the process of extracting water from surface or groundwater supplies, bringing it to treatment facilities, treating it to drinking water standards, and delivering it to residential and commercial customers expends energy – primarily because of pumping and treatment costs. The water sector consumes 3% of the electricity generated in the U.S. and electricity accounts for approximately one-third of utilities’ operating costs. Reducing potable water demand by 10% could save approximately 300 billion kilowatt- hours of energy each year. Water reuse systems, like rainwater harvesting, supplant potable water and reduce demand. The reduced water demand provided by rainwater harvesting systems translates directly to energy savings.

Collecting rainwater provides a safe, clean, reliable source of water and has many benefits available to the consumer.