BUILD YOUR OWN GREY WATER IRRIGATION SYSTEM – Part 1

July 13th, 2009 by Tim Leave a reply »

Part 1 – The opposition

Part of our renovations philosophy was to try and do some “Green” upgrades where practical and affordable. One of our earliest ideas was to do a grey water recycling system where the waste bath and shower water could be used for watering the garden.

Given that we live in a water scarce country and we do have every few years, quite severe water restrictions, I started wondering why more people didn’t have one already. Although a quick google did turn up some hits in Cape Town there was nothing I could find that was local (I wasn’t overly surprised). So I tried looking at some of the local hardware type suppliers but this proved fruitless, the only luck I had was at a rainwater tank supplier who sold a complete system which looked quite promising.

The system seemed at first glance quite cleaver as all it required was a standard 40mm (3/4”) in and out (overflow) and a plug point for power. The supply from the pump was a standard garden hose fitting. On closer inspection however I found it had the following weak points:

1. The pump was a standard submersible water feature pump – normally pretty reliable but with very poor flow and head (pressure) ratings. Can’t remember the flow but the head was only about 5m max. Also the impellors are normally plastic and prone to blocking.
2. To solve the blockage problem they had incorporated an oversized bottlebrush arrangement filter to keep hair and other nasties out – I read this as “needs regular maintenance” – not good!
3. The unit did have a kind of a sump, but its capacity was only about 2 litres – this means that if the flow exceeds the pumps capacity it simply goes to waste (kind of negates the whole point don’t you think)

Anyway I guess it will be okay for someone in a small townhouse who doesn’t mind a bit of hassle cleaning it out, but I decided I could do better.

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5 comments

  1. Ilze Sutherland says:

    We’re a plumbing company and would like to find out who can supply us with a grey water system for re-sale and installation purposes?

  2. admin says:

    HI Ilze – hope you came right – there are a number of companies selling units. If you needing something more custom give me a shout.

  3. Mark says:

    Hi Ilze. Have a look at the product available from Garden ResQ (www.gardenresq.co.za) Its a small effective grey water system that is easily installed and maintained. This just may be the product your plumbing company is looking for

  4. Case says:

    Hi Tim
    Since installing, have you had any problems with the Pedrello pump with regards to pumping water thats not totally clean (hair etc), since it’s only designed for clean water? Thinking of using the same pump, but also looking at small submersible pumps capable of handling dirty water. Limited options regarding submersibles though.
    Thanks

  5. Tim says:

    Hi Case – have been very happy as the model I used has a very sharp brass impeller which seems to chop up most of the hair. Having said that about a month back a wad of hair did jam the impeller – fortunately the thermal protection on the pump worked very well as I only noticed it wasn’t working after about 24 hours. Cleaned it out and its working as well as ever.

    Considering it has been running for well over a year and I don’t bother to clean intervene until it stops working I think it was a good choice. Any submersible would probably need monthly cleaning or a filter at least

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