Flexi Rain Tanks

Flexi Rain Tanks were invented in Melbourne in 2006 to save water affordably.  Ross Finlay, the inventor is an Engineer, with the very green philosophy of  “An Engineer does for a penny, what any damn fool can do for a pound”.  Here is his story of how the Flexi Rain Tank system came into being.

Just before the Melbourne stage 3a water restrictions came in, I looked at my silver birch trees in the front garden.  One looked sick, the other looked dead.  I went to the local hardware warehouse and was astounded at the cost of tanks.

The tank itself was just the beginning; there was delivery and installation.  They needed a concrete or boxed sand base, a pump, a little house for the pump, a flexible coupling to the tank, a first flush diverter … the list seemed endless.  I thought that while the people of Melbourne had made a good effort to save water, the industry was just making a killing rather than making it easier to save water affordably.  There had to be a simpler way.

There was.  The flexi rain tank was born, and because it was flexible, it did not need a hard base.  I also found a downpipe diverter which would send plenty of water to the tank when there was room for it,  but let any surplus water go into the storm drain when the tank was full, so no overflow, no flooding.  Best of all, I had water even when it was dry.  The simple design of tank meant I did not need a pump, I could open the tank lid, use a bucket to fill a water cart and take it to the flower beds without getting bucket back.   The 25mm (1”) outlet produced 40 liters per minute (3.5 timea the flow from my kitchen tap) and could also be used with a clockwork timer for a soaker hose or dripper system.  A stand was added so gravity could be used even more effectively.

I started to collect more water than I could use.  At first I just put more tanks up.  It only took 5 minutes to assemble one, so if the rain radar told me rain was  expected in 30 minutes and the tanks were full, I would just deploy another!  Soon there was not much garden left and I had 20,000 litres (20 Tonnes) of water.

A better solution was to connect the toilet, use more rainwater and save more mains water.   At this stage I admitted defeat and used a pump instead of gravity, but it was 20W, not 1000W, so I was using 2% of the power a typical plumber’s installation would use.  I did not need to squirt water across the garden through a hose designed for mains pressure.

Now I was not catching enough water, so I diverted more downpipes.  This meant I had tanks at three places in the garden, two near a downpipe and one far from its downpipe.  I hardly needed the water trolley now because the thirsty parts of the garden were never far from a tank plus I had set up some dripper & soaker systems.

I then realized that apart from not needing a hard base, overflow and pump the Flexi Rain Tank system had another advantage over the conventional rigid systems.  You can put them where you want them, they don’t have to be right next to a downpipe. Conventional systems including bladders use two runs of rigid 100mm PVC pipe, one at the top of the tank to fill, & one just below for overflow. The Flexi System uses a single, smaller, flexible filling pipe and does not need an overflow so it is much easier to locate tanks far from the downpipe if desired.

After connecting the laundry, our water bill was now down to 40% of the target 155 litres/person/day.  It was time to see if other people could benefit from the same technology.  I devised a trial to get feedback from users over a period of two years.  The feedback resulted in six improvements to the design and four new options.  I joined TiE the biggest entrepreneurs club in the world and  gained myself a marketing mentor and a patent attorney.  At the same time I consulted an industrial engineer and various plumbers.

The Flexi Rain Tank’s pedigree now reflects many inputs and real life experience, the objective is to “Keep It  Simple and Smart”.  A family of related products have our Green KISS of approval  because they support the philosophy of saving water affordably.