Rainwater tanks

In November last year, we were without municipal water for a few days - a frequent and ongoing problem for other Grahamstown residents living on higher ground - but rare for us as we're more or less at the bottom of the "manometer" of water reticulation in town.

Given that municipal service delivery is unlikely to improve in the short/medium term, I decided to plan ahead and set up two JoJo water tanks:

They're each 5000 litres, and about two metres high. The usual colour is a garish, presumably "environmental" green, but I saw some khaki ones on the Rhodes campus, and noted how unobtrusively they blend in. The tank stand was the most expensive bit, given the contractor was an aged German perfectionist intent on over-engineering things... there's probably half a metre more brickwork and foundation below ground level. He's probably right.

Seeing that we're eventually going to be drinking the rainwater for this whole exercise to make any financial sense, I installed two "first flush" filter/diverters. At first I tried designing my own - simple, according to Google - but getting the right PVC pipe fittings was a lot more challenging than expected. Soon after the tanks were installed, I attended the Albany Horticultural Society annual flower show late last year at the 1820 Settlers Monument, and at the JoJo stand saw a kit that contained all the bits and pieces for a first flush system. The helpful  JoJo rep directed me to the local Penny Pinchers, where it turns out I'd frequently walked right past these devices in fruitless pursuit of PVC fittings to do the same thing.

Modifying the original downpipe system wasn't too complex but involved wielding a hacksaw and drill while balanced on the end of a ladder intent on subsiding into wet soil:

The only challenge was discovering that the tubes of gunk in each kit weren't PVC Weld cement, but some sort of grease - presumably for the threaded end stop and giant O-ring at the bottom of each pipe column. When the joints hadn't set after a day, I cleaned off everything with meths, and bought a tube of the right thing, which set immovably in about two minutes.

These filters make a huge difference. The day after most rain, and sometimes in between rains, I clear them by opening up the "dribble" stopper at the bottom, and out pours about 30 litres of brown crap. It's amazing. If you don't clear it, the dribble mechanism, it can get blocked up with fine debris. Occasionally you also  need to clear the bottle brush type filters jammed into the pipes leading to the tanks. A sign that you need to do this is that the collector mechanism starts overflowing.

The tanks filled quite quickly, and I'm sort of sorry they're not bigger, although it was pointed out that getting enough angle on the downpipes would be a problem on a bigger/taller tank.I don't know if it makes sense to aim for a tank capacity similar to some multiple of your monthly municipal water consumption?

So far, these are just flashy garden tanks, The next step is to inject all this clean harvested water back into the house plumbing system, which involves a pressure pump. I bought one at BUCO. You can get a similar and I think cheaper version at Albany & Bathurst Engineering.

Together with the included pressure sensor that detects when a tap is turned on and powers up the pump, it's pretty much ready to install. The power is nearly in place, and I have a sleeve leading to the tankstand (thanks Andy Bradfield!). The plumbing has been extended using 13mm polycop all the way round the house to the tankstand, and I have all the fittings to connect the pump, not forgetting the non return valve between my house and the municipal main. I've even worked out the electrical connections between the pump and the pressure sensor by checking out my brother in laws one:

.

What's holding me up is the fact that my tanks are close to the street. This is South Africa, and unless securely mounted, it'll get stolen. I'm working on that... but will probably be galvanised into actually fitting it by the next water crisis/outage.

It'll eventually look something like this (a system installed by Brett Emslie from Albany Pumps, which links 4 tanks filled from a borehole, or by rainwater):

... and inject water on demand at a nice high pressure into the house plumbing.

I wonder if it'll help with some of my micro-irrigation runs where I've got too many heads?