This is Part 5 in the series “How to Build a Rainwater Collection System”.  Click to see parts one, two, three and four.

Steel water storage tanks for rainwater collection are generally bolted together grain silos adapted for this use. Made of galvanized corrugated steel panels, wall panels average 17 – 20 gauge with the galvanized roof panels being high rib or flat seam with a center hatch at the top and an access hatch near the bottom of the roof. A felt pre-liner is used between the steel and the main liner to protect it from abrasion. Liners are usually polyethylene and NSF approved when used for potable application or PVC, which is generally used for non-potable. However, PVC can be used for potable, as long as it is NSF approved.  RainBank recommends polyethylene for this application.

Steel tanks need to be built on a engineered cement slab with hold-down anchor brackets designed for the seismic zone where the tank will be placed. Plumbing for overflow, suction, discharge and any cross over lines used in multiple tank applications can either be PVC flanges, polyethylene or PVC boots if coming up through the cement slab. If penetrating through the side of the wall panels, PVC flanges will need to be used.

Steel water storage tanks offer durability and protection of the liner from UV rays, plus offers an industrial or rural architectural look. Many commercial applications use this type of storage for both of these reasons. Overflow lines can be installed on the outside of the tank, but it is recommended that any pressurized lines be underground and frost protected in our Washington climate.

Accessories include exterior ladders, platforms, and level gauges. The galvanizing does not need painting although if properly prepped, tanks can be painted to suit.

Assembly can be difficult for the homeowner or contractor, so it is recommended that a trained installer with the proper tools and knowledge be used.

Are you interested in building your own water harvesting system?  Leave a comment below.

Ken Blair

President at RainBank Rainwater Systems

A rainwater collection systems designer and consultant, Ken has designed and installed residential and commercial systems, primarily in the northwest United States for more than 10 years and, in 2014, began consulting and managing builds in other states. Ken is an accredited ARCSA Professional Designer / Installer and Life Member, the Northwest Regional ARCSA representative and advisor to its education committee and is available to speak about Rainwater Collection Systems design and builds.

Ken is a United States Navy veteran, having served on active duty during the Vietnam War era.

A career entrepreneur, Ken created a new business focus with a commercial dive company in Hawaii in the mid 1980′s to respond to and clean up oil spills, oil spill equipment training, service and maintenance for the oil co-op service industry. Ken is passionate about having a positive impact on the environment and is also a founding director of BANK-ON-RAIN (2011-2014), whose mission is to create grassroots solutions for rainwater collection for consumption and agriculture in developing areas of the planet.