It's that time of year when hundreds of samples start being taken from Northland's most popular beaches, rivers and lakes to check they are safe for swimming.
Summer water quality tests begin later this month and run until the end of March.
The Northland Regional Council has been monitoring bacterial levels at popular swimming spots over summer for more than a decade.
John Ballinger, Environmental Monitoring Programme Manager, said hundreds of samples would be taken from 47 coastal and 12 freshwater sites to check bacterial levels.
The results will be posted online every Friday at www.nrc.govt.nz/swimming.