The documentary makers visited Phuket in January and took samples from Nai Harn, Kata, Karon and Patong, according to a reliable source who wishes to remain anonymous.
''They are private film makers who were planning on selling their findings to a German television station,'' Phuketwan was told.
Questions about the quality of seawater at Karon beach were raised last year when a team from the German television travel show Wir retten ihren urlaub (We Save Your Holiday) found contamination near a wastewater treatment plant.
Plant officials later admitted partially-treated water was sometimes allowed to flow into the sea when the plant failed to cope with the quantity of waste.
''We staked out the tank/wastewater treatment system for 24 hours, all through the night and day,'' said German documentary team leader Ralf Benko.
''During the day right in front of the tourists, the hatch opened and concentrated water came rushing out, with children and families playing around the discharge.''
Phuket's Governor Tri Augkaradacha worked with wastewater officials to persuade the media that the discharge was a rare event and that problems had since been overcome.
However, with another German television crew working on post-production for their documentary and the team from 'We Save Your Holiday' likely to return to Phuket this year to check that changes have been made, Phuket pollution may again pose a threat to Phuket tourism.
The 'We Save Your Holiday' team will be hoping to report that the problem has been fixed but the findings of the second German documentary team appear to cast some doubt.
Untreated water is also known to flow into the sea around Phuket from resorts that prefer to operate outside the law. Anti-pollution laws are seldom enforced.
With privatisation of Phuket's public sands by commercial interests of all kinds, including five-star resorts run by expats, Phuket's beaches remain in disturbing decline.
Phuketwan has proposed creation of an idependent authority to protect and maintain all of Phuket's beaches with the revenue that now goes into the pockets of illegal operators and corrupt local officials.
A second German television expose is likely to heighten the concern of European tourists and lead to some of them looking at alternative destinations.
The documentary makers may create interest away from the beaches as well. While on Phuket, a female reporter travelled on Phuket's tuk-tuks, both by day and by night. Her conclusions are not known.