Craning in the tank; how the rainwater system works

The rainwater tank arrives!

. . . divertimento . . .

A brief description of the tank and rainwater collection system:

Tank Construction: Fibreglass
Capacity: 25 000 l.
Dimensions: 19'8" long x 8'6" dia.
Supplier: ZCL Composites (donation)

The system: All of the eavestroughs on the house run to a single point at the north east corner of the building. From here, rainwater drops into an 8" inflow pipe that runs underground toward the tank. The large diameter of the pipe is to prevent it from freezing up in winter. Near the filter, the 8" pipe breaks into two 4" pipes, which feed into the filter.

A submersible pump sits in the tank to move the rainwater into the house. The pump intake draws in water from within the middle of the water volume (not directly from the bottom of the tank). A layer of sediment may collect right in the bottom of the tank, and can be cleaned out periodically.

The rainwater will be used for flushing toilets and for outdoor watering. In the future, we hope to be able to use it for laundry and showers. Regulations don't currently permit these uses.
If the tank level drops too low (although this is unlikely, given its size), a float in the tank tells a solenoid valve in the house to switch over to city water, until the rainwater levels are replenished.

The rainwater collection system is also an important part of our site storm water management strategy. No storm water is sent off-site to city sewers. We have maintained permeable surfaces throughout the site; swales direct rainwater and allow for infiltration. The small amount of overflow from the cistern moves through a shallow swale and percolates into the ground.

. . . now, back to the feature presentation . . .

Unit Precast's craning truck snuck the tank through the canopy and brought it down site as far as it could reach ...













Then, the excavator picked it up and very carefully swung it into place.













...and everyone breathed a sigh of relief to see it settled in!

Big thanks to our project sponsors:

Unit Precast for donating their labour (co-ordinating and installating the system)

ZCL for donating the massive fibreglass tank!