Drinking Rain

Of course we all drink rain, one way or another. The water cycle eventually recycles all water into the sky and then back down to the earth, but some people drink their water a bit closer to when it fell as rain, than others. Sadly I’m not one of these people, but I look forward to the time when I have a rainwater tank.

the water cycle by John M. Evans, USGS, Colorado District

I just came across Greenfoot’s blog and her question about Sustainable House Day. Georgie commented on the Australia Street house in Newtown, Sydney.

The house incorporates all manner of sustainable features, including a ventilation stack and a low-tox or no-tox approach to paints and glues throughout. It also features a pool: a decadent, gorgeous plunge pool, tucked in a corner of the courtyard next to the living area, filled entirely by water from the house’s rainwater tank. [1]

As well as using the pool for a dip, it contributes to cooling the house. It sounds like a nice place to live. Georgie said,

All in all, a really great efficient house, and an amazingly effective use of space for 160sqm. It was great having the builder onsite conducting the tour, as he had all the knowledge you could ask for.

I’ve been meaning to write about Michael Mobbs’ sustainably renovated terrace house since Sustainable House Day on Sunday 9 September 2007 when I visited. I was in Sydney for my cousin’s wedding that weekend. We were staying in Glebe and the adjacent suburb Chippendale is where Michael Mobbs’ sustainable house is located.

The house incorporates:

  • rainwater collection. The tanks are underground and electricity pumps the water into the house.
  • on-site sewage (black water) and grey water treatment. [2]
  • a mini wetland out the back, watered by treated recycled water.
  • recycling of food waste using vermiculture (earthworms).
  • use of natural light where possible, and CFL for night time.
  • solar panels on the roof for electricity generation and water heating. When the sun provides too much electricity it’s sold back to the grid and when it doesn’t provide enough, grid power automatically switches on.
  • natural gas for cooking, space heating and boosted water heating when the sun isn’t shining.

Smartflo enclosed guttering My dad is a pathologist and whenever I talk about rainwater tanks he tells me that drinking from a rainwater tank is unsafe (he’s had cases of salmonella from rainwater tanks). This might happen if an animal died in the gutter or tank and contaminated the water, a possibility with older rainwater systems. Modern systems have covered tanks and gutters [3], like SmartFlo integrated gutter and leafguard system (which Mobbs used), thus contamination from salmonella is unlikely. The quality of Mobbs’ water was monitored fortnightly for 18 months and the data is available in his book Sustainable House [4]. If you were worried about water quality, rainwater could be used for the garden, washing and toilet flushing only.

watering the newly planted garden with recycled water Professor Patrick Troy, a Visiting Fellow at the ANU Fenner School of Environment and Society, recommends a filter to remove harmful bacteria [3] and a carbon filter would remove suspended particles. Mobbs’ house doesn’t use any filtering, except the first amount of rain to fall is flushed out of the system. Professor Troy also discussed the ease of treating sewage (black water) on-site [3], as Mobbs does. Although Mobbs and his family don’t drink this recycled water, his garden and the mini wetland love it.

Mobbs mentioned that some real estate agents say a sustainably renovated house may have its sale price increased by up to 15% and bidders in an auction will pay inordinately more for a house with a photovoltaic system on its roof. This concurs with Robert Silvey’s view that the installation of photovoltaic cells in his house in California will increase his home equity. The added bonus of solar panels on the roof is they act as insulation.

Michael Mobbs also mentioned something which he discovered after his renovation that would have lessened his energy consumption. Placing a refrigerator over an open cavity in the floor (with some sort of grill to keep out unwanted creepy-crawlies) allows cool air from the earth to cool the refrigerator and enables it to operate 25% more efficiently [4]. A refrigerator produces hot air from the top and this could be used in the room above. The example he gave was heating bath towels. I never knew people heated their bath towels, but that was one of the many things I learnt on Sustainable House Day.


Offline sources

  1. Right kind of splash (2007) The Age, 20 September 2007.
  2. Troy, Holloway & Randolph (2005) “Saving Sydney’s Water” Dissent, no.19, p.42-46.
  3. Troy, Patrick (2001) “The management of water in Australia’s cities” Dissent, no.7, p.28-32.
  4. Mobbs, Michael (1998) Sustainable House. Marrickville, NSW: Choice Books.

2 thoughts on “Drinking Rain

  1. I have always been told not to drink rainwater for risk of contamination, but never paid much attention. When I build however, I’m planning on having a 2 part (ie: carbon and sediment) filter attached to my rainwater tank, just to be on the safe side.

    I love the idea of a pool filled with rainwater – straight from the sky, that’s go to be good for you.

  2. I moved from the city to rural five years ago and during the first year could not bring myself to drink the tank water (old steel tank with a very simple mossie net filter). However four years ago I got myself a terracota chalk water filter and drink the tankwater with no ill affects at all. In fact there is only one problem with drinking tank water, once you have you cannot drink city water, but that is fine by me.
    My house is not connected to the water mains at all, and I have not filled my tank in the five years that I have been living rural. It is the best feeling imaginable (mmm lotto springs to mind but I digress). There is a guy in South Australia who feeds his grey water into a worm farm, the overflow from the worm farm goes into a fish pond and the overflow from the fish pond goes onto his veges. This will be my next project.

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