Christchurch residents are about to start tasting chlorine in their water.

The Christchurch City Council earlier this year, in the wake of the Havelock North water contamination episode, decided on temporary chlorination because its below-ground wells were not sufficiently sealed to eliminate the risk of contamination.

The water supply in the Brooklands, Kainga and Spencerville areas will be the first to be treated on Monday and by the end of April the entire city's supply should be chlorinated.

The council says the chlorine may react with organic content in the pipes and dislodge it. Residents should run their taps for a few minutes until the water clears.

The taste of chlorine might be noticeable at the beginning of the treatment process "but the taste will become less noticeable the further away from the pump station you are".

The chlorination is expected to last for a year while about $800,000 worth of work is carried out on the city's 103 boreheads.