Home Forums General Discussion Grey and black water systems Reply To: Grey and black water systems

Scott Willis

Hi Panapa,
Local councils can make this simple or a challenge. In our neck of the woods, there are many different systems, some fully permitted, others not, and some original. Good and bad systems exist in both permitted and ‘independent’ systems. Good to ask about systems at your council – they may know of sensible solutions (particularly if an EcoDesign Advisor works there ; )

The most expensive system is probably a septic tank that mixes both grey and black water – beware of any that require oxygenation 24/7 as the ongoing costs are equally good at making dollars disappear as much as waste water.

Eliminating black water from your waste stream by using a composting system POTENTIALLY makes a cost effective and sustainable system possible. There are many composting toilet options now (even with a flush – water – system). At my own house we designed and had made up (polypropelene) a dry composting toilet based on the BioLoo system. Our toilet is located at the end of the laundry, accessed by the back porch (not inside the house – earthy smell, occasionally whiffy if too much moisture). The worms thrive in it (its not a hot compost).

That still leaves the grey water to deal with. Grey water that doesn’t involve cooking water, sink, etc, is much easier to deal with. (Kitchen sink water is full of fats, solids, etc) Now it depends on whether you want an off the shelf option or design and build as you go.

A grey water system I know well uses gravity to direct water into a gravel filled old bath (first filter) then drains into a wet area of bush. This drained water could just as easily be directed to more useful places. (The water from the kitchen sink first goes through a grease trap). This system depends on A). Gravity (slope), and; B). Land area (enough to have a wet area/evaporation zone).

If you want to go down the simple system route its probably best to ask around and try to get a hold of plans that have been approved for something you like (if seeking formal permission – you should always make sure it works well whether approved to regulation or not though).

I hope that helps a little.