My Cheapo Greywater Irrigation System

Like many people concerned with water use and reducing the impact of my excessive capitalist wasteful bourgeois lifestyle I decided to put my greywater to better use. It’s easier than putting my greymatter to better use, and arguably a more valuable resource.

I had a few ideas I wanted to stick to, as well as keeping it within reason from council approval. You’ll have to read up on your own council approvals for greywater. I’m basing mine on the “I won’t tell them and they won’t care” legal principle.

The main principles I wanted were

1. No storage – stored greywater will build up bacteria and needs space. Althogh up to 24hrs is acceptable, no storage for me.
2. Shower / Bath / Sink / Laundry only. My kitchen water goes down the normal wastewater system, meaning no grease traps to worry about.
3. Minimal Maintanance – small holes clog up, it had to be robust. Greywater contains hairs, soaps, grease, dirt and who knows what else that falls off my kids.
4. Subsurface – I wanted the water delivered under the mulch and into the soil
5. Cheap, very cheap. That means no pumps or commercial kits.

These are the trees I wanted to water. Greywater would be perfect irrigation for my 16 tree orchard. My sloping block made this much easier, although it would work on a flat block. Uphill – forget it.
This nasty looking contraption guarantees things work smoothly. It’s an overflow pipe and diverter valve. Details below.
The diversion valve. When I have too much rain, I turn the valve, and greywater goes back to the council. I used 25mm corrugated greywater pipe to get to the trees.
Overflow pipe – if the greywater can’t escape fast enough  – say when the kids let the water out of the bath whilst I am having a shower – it will fill1.5m of  vertical pipe on the right, then overflow into the kitchen drain pipe on the left. The air-valve is to stop airlock / siphon issues.
The first tree also gets a 1.3m overflow pipe. If there is a blockage lower, or too much flow, it simply comes out here. This is below the level of the house. Make sure yours is too.
1″ (25mm) poly and 1″ poly pipe Y piece.I use the cheapest low density irrigation poly I could get. Hose clamps were not needed.
1″ poly, 1″poly T, and an end stop using a cable tie.
The magic ingredient. The 1″ poly fits perfectly into these water spikes. They are $0.99 from Bunnings and designed for use with softdrink bottles. They deliver a perfect amount of water.
A better shot of the holes. I tried enlarging the holes initally – bad move. The factory size is perfect. Larger holes stop downstream spikes getting water.

The only thing that has to be done is the spike washed out / replaced every 6 months approx. No filters, no smell, no pumps, no cleaning, no worries. The ends of the pipe don’t appear to collect rubbish, and the system is pretty foolproof and self regulating. It’s all easy parts that should last long term, and be dirt cheap to replace.

I had the luxury of a high set house and a sloping block, giving me plenty of fall and water flow. Your mileage may vary. It gives me cheap year round irrigation. Long showers are not wasteful – they are a benefit.

Longer term I would like to find / make a sock filter to go inline with a disposable sock – but I haven’t found one yet.