Tank water cheaper than groundwater, says CEN

Rainwater tanks could provide a more reliable, more economic and more environmentally-sustainable solution to the Peninsula's drinking water needs than groundwater extraction, according to the Community Environment Network.

Network chairman Mr John Asquith has told Peninsula News that, based on a study the Network had commissioned from economic consultants Syneca, tanks would be cheaper per household over a five-year period.

They would also have minimal on-going operating costs beyond that period compared to the $1.5 million estimated to operate the groundwater system, he said.

Mr Asquith said the groundwater extraction scheme would supply 7000 homes at current usage levels, at total of 1400ML a year.

"This is presumably going to be treated to potable standard and there will be monitoring, running and maintenance costs," Mr Asquith said.

"The presentation I saw by Gosford Council said they were going to inject treated effluent into the perimeter of the aquifer and this would stop the groundwater ecosystems drying out.

"But I would be surprised if NSW Health have approved this for potable usage as there is nothing to stop the mixing of treated effluent and groundwater.

"I have not had a chance to read the plan in detail, but these questions need answering as they impact on water quality and the costs."

Mr Asquith said the $8.3 million cost to construct the groundwater extraction infrastructure would not include yearly operating costs.

He said yearly operating costs would be high due to the use of effluent, pumping and the need for monitoring of water quality.

He estimated these costs would be as high as $1.5 million per year.

Mr Asquith said that the Syneca report assumed a conservative yield of 81,000 litres per year from a 3000-litre tank.

"This is close to 40 per cent of the average households usage," he said.

"So the equivalent water saving with tanks requires 16,800 tanks."

He said that based on Syneca report costings, this would amount to $37.8 million.

"The Syneca report was based on a loan from council for a 3000 litre tank system to keep costs down."

Mr Asquith said the Community Environment Network had wanted to determine the financial impact of the two scenarios on the customer:

He said groundwater cost per household would be $1400 for the first year with an additional $214 per year to run for four years.

After five years, the total cost to each ratepayer would be $2256 plus externalities in environmental costs.

The comparable figures for tanks were $2250 plus about $20 for electricity for the pump.

"After five years cost is $2350," said Mr Asquith.

"But tanks save you about $150 per year in water rates.

"So the net cost to ratepayer after five years is about $1600 plus there is a reduction in externalities costs with tanks.

"These calculations are usually done to minimise cost to council not the ratepayer.

"Tanks are about twice the dollar cost for councils as twice as many are required.

"However, they reduce costs to residents over time due to free rainwater."

Mr Asquith said the report did not include subsidies "as these distort the economic model" but if they were taken into account they would make a significant cost difference to the consumer.

Mr Asquith was critical of the "Not for Drinking" labelling required as part of the rules by NSW Health which council have to enforce in any tank installations it approves.

However, he said: "Changing the rules to allow the use of rainwater for laundries, toilets and in hot water systems involved a huge amount of campaigning over five years.

"So we are much better off now.

"Some studies have shown that rainwater tanks actually purify the water provided they have strainers.

"Councils and water authorities always make it hard for tanks.

"Why? Less income from water rates? A reduction in their power and control? Distrusting the public?

"There are probably a few other reasons as well."

Media statement, August 31 John Asquith, Community Environment Network