Thanks Greenlight for the vote of confidence.

Malcolm Turnbull, can I respectfully ask you to enter the debate that you have triggered and respond to some of your detractors.

Thankyou.

Thanks for the timely DCF/NPV stuff, Sylvia. The costings for the 13.5kl tank options were based on 7% over 30 years.

Lowest cost rainwater supply: why don’t Governments want it?

NSW is the only State where building approval is conditional on reducing mains drinking water consumption (by 40%). Other States make building approval conditional on installing rainwater tanks. NSW’s BASIX law is honest because its explicit purpose is to conserve mains drinking water. NSW plumbing policy also is honest – see Hansard, Hon Frank Sartor, 16 September 2003 http://www.parliament.nsw.gov.au/prod/PARLMENT/hansArt.nsf/V3Key/LA20030916011

The NSW Government so far has dealt with 20,000 certificates issued under its BASIX law. There are 1.7M separate houses (70% of dwellings) in NSW (ABS, 2001). Will it take more than 100 years for BASIX to apply to all houses?

No State Government makes rainwater tanks mandatory in existing houses because water collected from roofs for rainwater tanks is not owned by the State.
Perversely, no state Government confirms that water collected from roofs for rainwater tanks is actually owned by the building owner.

All State Governments have the legal right to mandate reduced mains drinking water consumption at point of sale of all buildings, with rainwater tanks being deemed to comply. Dwellings sell on average every seven years.

In a decade, most dwellings would be required to reduce mains drinking water consumption. All house owners will pay less than at present for installing a rainwater system. At $3,000 per installation, rainwater supply will add 1% (or less) to the cost of an average house – new or existing. Rainwater supply is a building cost that is depreciated as part of the building, with an operating cost (house) of $0.40/KL.

In summary
· all Governments want houses to have rainwater tanks
· lowest cost is when rainwater supply is installed in all houses
· 5 million household installations can be accomplished in 10 years without mandating rainwater tanks

All Governments can mandate reduced mains drinking water consumption at point of sale of all buildings with rainwater tanks being deemed to comply. Why do they choose not to? Don’t they want every house and every building to have their own rainwater supply, within a decade, at lowest cost?

Greg Cameron

Perseus,

I have repeatedly tried to get people at least to believe in the ideas behind DCF/NPV, even if they don't fully understand them. I seem to be beating my head against a brick wall on this. GC has clearly ignored my previous posting, and is just restating his flawed argument.

It's not just with water that these issues are arising, of course. Power is another one. Yet if people don't (or won't!) understand how costs need to be calculated, they end up being more receptive to the whole "big business conspiracy" idea that's constantly circulating.

That wouldn't matter, except that it's pushing governments down a needlessly expensive path.

As regards your own 13.5Kl tank proposal, have you thought about whether any cost should be attached to the land on which it sits? The version of the tank I found online covers an area of 7 square metres.

Sylvia.

Of course we must work out the economics of providing water, it's the most important aspect of the situation. Sylvia mentions power as another add on to the situation, but aren't you all missing the most glaring problem to face.

How does Sydney or other cities on the coastline cope with sea rises in the next decade or so, of many metres. I sat and listened to a CSIRO climatologist the other day, stating the effects are happening 50 and 100 years before they were expected.

He said at the current rate, the seas will rise a minimum 7 metres within 10 years. But because we are increasing our output of warming gases, they have no idea whether it will be 2 years or 10. What he did say was, we have a different situation in Australia because we are surrounded by sea, so the effects for us will be unseen until like a boiling pot, it overflows and the seas rise in huge surges, but won't retreat until the earth cools. He also said within 30 years they will rise up to 70 metres.

If this is true and he said all the data from the Antarctic supports the data from the Artic, don't you think working out the economics of water is useless. When the seas rise, so will the rivers, flooding the plains. It will also flood inland Australia. I found this frightening to contemplate, except I live more than 100 metres above the sea. But close to 90% of Australians live below 100 metres and within 5 klms of the sea, below the coastal ranges.

We saw the tsunami of Indonesia, will that be what it will be like when it happens. It will happen in summer when its warmest and most people are holidaying on the beach. How do you cope with walls of water that don't retreat. Could someone give me the economics of what should be done about that, economics will save us, won't it.

Sylvia,
I don't think any elements like land area should be included because they are already in place and are already being paid for. But you raise an interesting issue of multi tasking of water tanks.

It is ironic that I can build a 1.8 metre brick fence on my front boundary but cannot put a set of slimline water tanks of essentially the same dimensions within 6 metres of that boundary. Yet, this is a classic case where the tank could provide a dual function but is being prohibited by Council regulations.

A brick fence can easily cost up to $300/lineal metre, both the bricks and the tank need a solid foundation, so the cost of the tank can be off-set by the savings from not building a fence. I seem to recall that a 2.4 metre long slimline holding about 3,000L costs about $700 which is about the same as a similar length of brick fence. And given that one has chosen to have both functions then it is quite reasonable to discount the cost of the tank by the savings on the fence. Unless, of course, you already have the fence.

The same can be done with garage walls, garden shed walls and even house walls (for excellent heat transfer and sound proofing qualities) etc but in far too many cases there is some stupid bit of Local Government BS in the way. Either way we have hardly started to think about solving on-site water storage issues