Rainwater Catchment, Water Tanks

Considerations for Underground Water Storage Tanks

3 Comments

Xerxes underground tanksRainBank is experiencing increased interest in underground storage for our Seattle customers, requiring special considerations for underground water storage tanks.

Aesthetics and available space are the most common reasons from these customers. Many are building larger homes on small lots that once had a 1,200 square foot home with a front and back yard. New construction is trending towards a larger footprint, leaving less room for water storage tanks. Slimline tanks allow for less visual impact, but are restrictive on volume. Other residents are remodeling older existing homes that still have yard space available – and are looking for greater amounts of storage.  Below grade storage can be the answer, leaving a yard area that can accept landscaping right over the top of the water tanks.

Here are some things to consider with underground storage.

  • First and foremost – costs. Below grade storage will require excavation and. most likely, exporting much of that soil, which would have to be loaded and trucked off site.
  • Drainage needs to taken in account, with the new City of Seattle stormwater rules preferring infiltration for overflow. Where infiltration is not feasible, connection to the city storm system can be implemented for overflow as long as caution is taken to prevent sewer gases  or back flow from entering the tank.
  • Water tanks need to be properly vented and have a riser to access the tank for periodic cleaning and pump service. The installer must be sure that plumbing will not be compromised with slight settling or shifting of the tank.
  • Below grade tanks tend to be more expensive to meet engineering requirements of underground tanks, and once installed, are considered a confined space and caution must be taken if access is necessary. 

Underground-Tank-Construction3-1038x576For those who understand the considerations of underground storage, you have the luxury of landscaping that is free of visual impact and have different available options in tank sizes, styles, and materials. Tanks can be single or multiple, plastic or fiberglass. Cement tanks can be used for non potable use or lined with a NSF certificate for drinking water. 

Infrastructure, Sustainability

Rainwater Collection Can Cut Demands on Urban Water Supplies

Space_Needle_Mount_Ranier_Seattle_Washington_USAUrban growth, especially as seen in Seattle, can actually help cut demands on city water supplies. Still valid today, we wrote about this in July 2014 under the title Rainwater Collection Reduces Dependence on City Water in Seattle. Read more below:

As anyone who lives in Seattle can see, there is a massive amount of rental construction happening. With the growth of the South End of Lake Union and the Ballard area, over 23,000 units are expected to be added in the next few years.

A cultural shift in water conservation with simple technology can reduce the amounts of water usage through more effective water management practices. While the “Green Storm Water Infrastructure” or GSI mandates that runoff from impervious surfaces is to be infiltrated on site, other innovative and effective technologies are crucial in reducing the need for upgrading and expansion of sewer and centralized water systems.

Think of the reduction of the amounts of water coming off our roofs into stormwater if we diverted that water to usage such as toilet flushing and laundry facility. This practice could cut runoff by as much as 50% in high density housing complexes, while saving hundreds of thousands of dollars that would be used to meet the demand.

Bio swells and rain gardens do very little for infiltration during the rainy periods when the ground is already saturated. Rainwater collection used for toilet and laundry facility could be using that water during those months rather than having it overflow, and it would reduce the run off during those periods. The end product would be reduction of stormwater runoff, less dependence on city water and its infrastructure, cost savings to the building owner and tenants, better use of our natural resource, while reducing pollutants in our waterways.

Learn more about rainwater collection and whether it is a good fit for your home or commercial project. Use the form below to request a quote for a feasibility study.

Potable, Rainwater Catchment

Proactive in the Advancement of Rainwater Collection

mt.rainierRainBank has always been proactive in the advancement of rainwater collection. We designed and built the first potable system in Seattle, as well as the first potable systems in Skagit, Jefferson, and Whatcom Counties.  

Additionally, we have been designing and building rainwater collection systems for potable and non potable demands for more than 15 years throughout Washington and Oregon.

RainBank began in San Juan County, which at that time, was the only county that allowed rainwater harvesting in the state. San Juan County had an exemption to the state’s water rights laws that considered rainwater a tributary and therefore not subject to those laws. It wasn’t until 2009 that Department of Ecology convinced the legislature that rainwater collection was beneficial and therefore should be allowed. More counties began to come on board to allow  the use of treated rainwater for potable use, with King County adopting in 2011. Since then, many counties in Western Washington now allow the practice, but there are still those who have not.

We were recently contacted by a customer from Wahkiakum county in southwest Washington, who wished to use rainwater collection for potable use on his property. The spring that was grandfathered in did not pass the last well report and was deemed unsafe for consumption. I petitioned the county health department for acceptance of a sole source potable system and was told they never heard of the practice. I sent documentation from Department of Ecology, King County policies, ARCSA (American Rainwater Catchment Systems Association), a list of Washington counties that have adopted rainwater use, a few case studies, and our website.

I am pleased to announce that Wahkiakum County responded that they will consider a design for residential potable use for this project.

It is through experience, expertise and commitment that RainBank Rainwater Systems is the leader in Washington State’s rainwater catchment industry.

Rainwater Systems