06 May 2019

Christchurch’s drinking water could be chlorine free as soon as the end of July.

A water tap.

Christchurch's water should be chlorine-free by the end of July.

The Council will this week consider a report outlining options around continuing chlorine treatment of its water supply.

Read the report.(external link)

Seventy-five per cent of the water supply is expected to be chlorine free by the end of this month, which marks one year since chlorine treatment began to allow the upgrading of the city’s 140 below-ground well heads.

A total of 47 well heads have been upgraded to date, and work is currently under way or scheduled at a further 54 across the city.

Water Supply Improvement Programme Manager Helen Beaumont says getting the work finished as quickly as possible is a major priority for the Council.

“We know getting back to chlorine-free drinking water is very important for residents, so we are working as hard and as fast as we can to get the final well-head upgrades across the line for the city,” Ms Beaumont says.

“We had originally signalled having 90 per cent of the water chlorine free by the end of May, however a number of delays in the work programme – including finding fewer wells eligible for quick, temporary upgrades – have slowed the timeframe down slightly.

“But we’re on the home straight now, and we appreciate the ongoing help from residents to conserve water while restrictions are in place for Christchurch and Lyttelton Harbour.”

Ms Beaumont says chlorine treatment would continue to affect part of Christchurch’s central water supply zone until the end of July, including households in Sydenham, Beckenham, Opawa, St Martins, Spreydon, Hoon Hay, Cashmere, Bowenvale and Huntsbury.

To end chlorination in July, the Council would need to reconfigure its water supply network to mostly use pump stations supplied by upgraded wells, while keeping some chlorination equipment on standby until September in case of spikes in water demand.

“There could be times between July and September when we need to temporarily reintroduce chlorine to some parts of the city so we can meet demand and keep the water safe for residents while we complete our work,” Ms Beaumont adds.

An ultraviolet treatment plant at the city’s largest pump station, Main Pumps, was scheduled for completion next month but has since been pushed back to September due to the discovery of asbestos.

The materials are not in contact with the water supply but need to be carefully removed and disposed of before work can start there, Ms Beaumont says.