A free water audit service is being offered to Aucklanders wanting tips on saving water.

It comes as residents are asked to use 20 less litres a day after recent flooding disrupted the water treatment process.

Watercare sustainability manager Rosaline Klein said anyone interested in cutting back can have an auditor sent to their home.

"People on average save 50 litres per day per person following that service, so it's really popular."

The audit service has been on offer for several months, but Klein said it has become more popular in the past few weeks.

"The response is really good, it's basically a free service that helps people live their life more sustainably and save money."

The service is run in partnership with EcoMatters.

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