This term really sums up the nature of much of the debate about the future of wastewater disposal for Christchurch.

Grey water is what is left after we have done the household jobs like washing dishes, clothes, and of course, ourselves.

Unlike much of the world we do not even have to think about washing the whole lot at once because, in a global context, we have a luxurious supply of fresh water at hand.

It is a situation that we have enjoyed all our lives.

In many countries grey water increasingly is used many times over.

They do not have the luxury of choice; water has become too valuable a commodity not to be used to the maximum possible point.

Here in Christchurch we are still developing a wastewater strategy that will take us into this new century in a healthy and sustainable fashion.

Which is, in part, why the term "grey" water takes my fancy so much for summing up the nature of the debate we still need to be having.

In a way it sums up where we really are at the present point in the debate about how we dispose of our waste water, sewage included.

It is an issue, or rather set of issues, where, once again as the debate shifts, we will hear huge efforts to again convince us that it is all a very black and white matter.

It isn't.

Just as life persists in refusing to act like the movies so too does the business of good governing refuse to obligingly line up in terms of black and white decisions.

Most of the time in the adult world we find the rash decisiveness of our youth makes way for the reality that a lot of the time we are dealing in shades of grey.

Part of that involves being prepared to listen to advice.

I believe that our decision to drop our Estuary outfall plans in favour of an ocean discharge application is a sign of political and administrative maturity for this Council.

In the simplest terms, when science shifted the goalposts we accepted that we were now in a new game.

Some of the old rules do still apply.

We still need as a city to resist any efforts to rush us in the journey toward arriving at the best possible decision.

This is the once-in-a-century decision that we have to get right.

We will all have to be prepared to do the right thing, not the cheap or politically expedient thing. I believe that the vast majority of the public understand and support this position.

It is a case where I hope you will not opt to be silent and let the debate again be clouded by those who would shout the loudest in order to prevail.

The evidence pointing toward our need to use the ocean is now much stronger than it was before.

While we need to move ahead to respect that evidence we also need to make sure we leave ourselves the flexibility to adjust to changes and opportunities that may arise along the way.

Just as we need to acknowledge the new science that has led to our change of position we must also keep an open mind to other changes science may provide in future.

It will all prove a careful balancing act where the voice of the public must be heard as we proceed.

I'll be keeping my ears open.

Gary Moore

• www.christchurchmayor.org.nz