Murky Rainwater Tank with The First Flush Diverter and Filter Screen

Hi all,

With the recent muddy rain in Melbourne, has anyone used the first flush diverter and filter on their rainwater tank and found it works and useful?

Been thinking to install one but if no use, perhaps just flush the water out every now and then (what a waste!)

Poll Options

  • 6
    Yes, works fine for me
  • 0
    No, save money somewhere else
  • 1
    I have a different approach...


  • +1 vote

    A first flush device will not solve this problem - the entirity of the rain is muddy, not just the first bit.


      A first flush will assist though, allowing the dust settled on the roof to be flushed away and then the muddy rainwater goes to the tank. at least it will be clean muddy rain and not doubly dirty from the roof dirt.

  • +1 vote

    I have a first flush on my tank and other than dirty rain, the other issue is how they operate.
    they have a slow drip hole and you can vary the size by the different fittings given for a slower or faster drip,
    don't set it too big as too much water will run out of it, too small and it doesn't really let any water out, plus gets blocked straight away..
    You must take this off and clean it, as it gets blocked, I would suggest after each decent rain, not light shower, there's a lot of sediment that comes down.
    Plus the longer the pipe the better for the first flush, once the float ball comes up and then diverts the water, most of the sediment from the rain, roof and gutters will hopefully be in the pipe, and cleaner water going into the tank..

    Make sure
    you keep your gutters clear of debris and sediment, you would be surprised what remains in the gutter.
    all tank openings need to have mozzie fittings to ensure you don't create a safe haven for breeding them.


      Thanks, I have gutter guard, do you think this would help?

      I suspect there is no such maintenance-free first flush diverter?


        I’m not sure it is entirely necessary to have the ball valve as part of the first flush. If there is. O ball valve once the first flush chamber is filled the remaining water will flow past anyway. Might get a little turbulence at the top, but it won’t be much.


    I have gutter guard

    Gutter guard only stops twigs and larger debris from entering your gutters/tank.

    Smaller items like leaves etc quickly break down and fall through the gutter guard mesh, turn to sludge, and eventually end up in your tank.

    I tried gutter guard once and ended up throwing it away as it made actually cleaning the guttering more difficult - and didn't work too well.


      Hm…the gutter guard installer told me, I don't have to do any maintenance whatsoever, I guess mine is special? Or…they are telling lies to me…

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