water tanks

Cleaning the gunk out of our water tanks

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It’s coming up on eight years since we installed our first 5000L water tank, put in during drought conditions. Since then we’ve added two more tanks as part of the renovation.

Over Christmas, when we had three dry months, our tanks dropped to nearly empty. They also started to stink, clearly the results of anaerobic decomposition of the plant material washed off our roof. Smelly water feeding into the washing machine, not good!

Our setup has first flush diverters, designed to capture the first lot of dirty water that flows into the gutter. They’re not magic, however, and gunk still gets in to the tanks, and builds up over time.

In the country, where households have to rely exclusively on their water tanks, it’s routine to get them cleaned out every while. I haven’t heard of it being done in the city, however. This might be because most of the tanks were put in at the same time as us, or later, and the problems are only now starting to emerge.

When we were out at a country show, we collected a business card from Leigh’s water tank cleaning, who we talked into dropping by our place when he happened to be heading into the city. We also talked to the Water Tank Cleaning Company who operate throughout Sydney (their website was down at the time of posting).

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Leigh, showing off his tank cleaning setup

Leigh was very friendly, the the process is surprisingly simple. It’s basically a hand-manoeuvred version of a pool cleaner, which is steered around the base of the tank where the gunk has accumulated.

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This is the dark brown water flowing out, at force, from our tanks

It’s somewhat horrifying to see how much dark brown water gushes forth. No wonder our water filters kept getting clogged up, trying to deal with all that!

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This is the view down into one of the tanks: the white area is the bit that’s been cleaned…

It’s a quick process, and within half an hour, our two main tanks were done. That should keep them going for a few years…

Lewisham House is featured today in the Sydney Morning Herald

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The news is that Sydney Water has decided that it doesn’t need to save any more water, and that programs for schools, businesses and schools can be shut down. It’s an extraordinary decision, made with the full knowledge that Sydney will only be getting drier in coming years.

Our house was the featured “human interest” angle for the story, and a video person came around yesterday to film me watering the garden and talking about why we put in our water tanks. All good fun!

You can see the video here, including shots of our water tanks in full operation during a brief thunderstorm:

Water wise, dollar dumb

Update: I’ve just discovered that we’re on page 2 of the printed newspaper, and there’s also a second article online that includes more about the house:

Dam the expense: rebate gone but tanks for the memories

Water-wise water spikes

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Water spikes that we use throughout our vege patch
Water spikes that we use throughout our vege patches (and beyond)

A key element of our watering system, fed by our rainwater tanks, are the “water spikes” used in the beds themselves. I was sure we’d written about these when we first put them in, 3+ years ago, but I can’t find a post for them. So here it goes…

These spikes are traditionally used with grey water systems, as they have two pairs of drainage holes 10+ cms down (the regulation depth for grey water usage). According to our plumber, one spike feeds about a circle about 1m in diameter. To be on the safe side, we’ve got three for each raised bed. (We’ve also strategically used them throughout our new native garden at the back.)

The big advantage of this watering approach is that practically no water is lost to evaporation, as it all goes sub-surface. It also encourages plant roots to seek downwards, strengthening them again dry and hot days. It’s robust against blockages, as any sediment simply falls to the bottom of the water spike.

We had a whole bag of spikes supplied as part of our water tanks, already made up. But you can also make them yourselves, as follows:

  • orange water spike (our plumber called it a ‘carrot’, for obvious reasons)
  • 25mm end cap (standard item for 25mm polypipe watering systems)
  • 3.5mm hole drilled in the top of the cap
  • standard 4mm elbow inserted (heat the cap in hot water first, and use pliers)

This creates a ‘watering unit’, when then connects to standard 4mm polypipe (used for drip feeds, etc).

I’ve seen the ‘carrots’ available per piece in Bunnings, along with the other required bits. You can also get them in bulk at Reece.

Combined with a timer system and a network of 19mm polypipe, this is a great set-and-forget watering system for all our plants. We love it, and would recommend it to others.

Water spike in the ground (note the 4mm elbow inserted into the end cap at the top of the spike)
Water spike in the ground (note the 4mm elbow inserted into the end cap at the top of the spike)
The water spike in place, attached to our 19mm polypipe network.
The water spike in place, attached to our 19mm polypipe network.

 

Finally some rain!

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Sydney rain radar
Sydney rain radar

It’s been a long time coming. As an “inner-city farmer”, rain becomes an important thing, closely watched and hoped-for.

The main vege patch has a watering system, but the tanks ran dry a week ago (all 10,000L), forcing us to switch to mains water.

The food forest at the back relies on rain. And there hasn’t been rain of substance for six months now, leaving the ground parched and the plants struggling.

Finally, it rained last night, as shown above. And it’s kept raining today, heavily at times.

Rain on Christmas Day, not normally considered a good thing … but great for the plants. We’re relieved.

Our third (and final) water tank went in this week

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A grey, rainy day … and perfect timing to get our last tank installed.

One of the first things we did when we purchased the house was to put in a water tank, to allow us to grow our own food despite the water restrictions in place at the time.

The renovation gave us an opportunity to expand our water capacity. The easy step was putting in a second 3,100L water tank in beside the first, at the side of the house. Since this one could just be connected to the existing tank, it’s pretty cheap (no pumps, plumbing, etc).

The last water tank was a slimline tank, put in to address our overflowing gutters. With the extension finished, we had 150 square metres of roof feeding the back gutter, and with a single downpipe, it would get overwhelmed in heavy rain.

The slimline tank on the other side of the house allowed us to put in another downpipe. By connecting the new tank to the existing tanks, the water level equalises between them, adding 1,500L to the total capacity.

So that’s 9,700L of water capacity, split across three tanks in two different locations, with just one pump. Not too bad!

This diagram shows how it all fits together (click to see a larger version).

Visit our house (and others) on the next Marrickville Council WSUD tour

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Marrickville Council has organised another Water Sustainability Urban Design (WSUD) tour in the local area, and we’re one of the stops.

The purpose of these tours is to show local residents some of the many ways of saving water. In our case, it’s our water tank, irrigation system, and permaculture garden sufficient to meet our vegetable needs.

To book, download the poster, ring Marrickville Council on 9335 2222, or email water@marrickville.nsw.gov.au.

See you on the day!

Becoming a sustainable water ambassador

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The sustainable water ambassador poster

When we put in our water tank early last year, we received a rebate from Marrickville Council, which was much appreciated. This also started a dialogue with the water folks at the Council.

As a result of this, I agreed to become a “Sustainable Water Ambassador”, and the details on this have just gone live.

There are details on the overall programme, as well as the poster (PDF) showcasing what we’ve done.

So far this hasn’t involved doing much, although we were one of the stops on a local tour of water sustainable houses. I’ve also been invited to be a member of a Council working party on sustainability, which should be interesting.