Install Urban Water Tanks

Lyndall Hancock has spent a lifetime with a rainwater tank beside the house.
Over the years, the Dunedin woman has used water collected from the roof – running down through pipes to a tank beside the house – for cooking, cleaning and even drinking, once strained and boiled.
Now aged 80, Miss Hancock lives in Waverley and still uses rainwater harvested from her latest tank to water the garden.
She told the Otago Daily Times the time was right for the Dunedin City Council to consider offering incentives to urban homeowners wanting to invest in similar schemes.
As well as everyday uses, the tanks promoted water conservation and could help ease pressure on council water services, Miss Hancock said.
The tanks would also be useful as an emergency supply, should earthquake damage in Christchurch ever occur in Dunedin.
“It used to be that houses all had a rainwater barrel. When I was a child, we had that at home. I can’t remember what the water was used for, except that when there was a drought there was always water there for the vegetable patch.
“It’s sensible. We could run out of water as quick as look at you,” she said.
via Water-tank advocate calls for incentives. {Otago Daily Times}
 
Craig Brown of CBConsult.co.nz contributed this diagram showing a safer configuration for water capture.  He mentioned he forgot to include the block of concrete at the bottom of the tank to keep the water slightly alkaline:

There are various options for water tanks, including oval and rounded rectangular tanks as seen in this SHAC(2009) Team Housewise retrofit: