Sea Quality

Sea water quality maps of Koh Samui, Koh Phangan and now also Koh Tao and Phuket are available below, and data available for Ang Thong Marine Park. Additional test data will be added to the maps with future updates.

Water samples are taken from sites around the islands and analysed according to the Thai government Marine Water Testing procedures for a wide range of possible chemical and biological contaminants (see Marine Water Testing Document below for full details).

If the water sample passes all tests, and are within the prescribed limits, it is given a green pin.

If the water sample fails one or more tests, but by no more than 50% of the limit, it is given a yellow pin.

If the water sample fails one or more of the tests, and is more than 50% over the specific limit, it is given a red pin.

To date, all samples that have failed to be within government limits have failed primarily on the basis of coliform bacterial count. All test data is for the period 2016-2018, updated annually.

Should you require more detailed analytical data on the specific sites and tests, if you want to know the precise analysis position, or if you are interested in testing at a specific site, at your own resort or business , please contact us via the email address to discuss further.

If unnatural events or Marine animal deaths are observed on the beaches of Koh Samui, Koh Phangan or Koh Tao, or indeed any other region, they can be reported to the Marine and Coastal Department using the appropriate phone number from the map HERE

Air quality data for Thailand is available from the site Air4Thai

Water Quality Koh Samui Map (2018 updated additional testing sites designated with red *)

Water Quality Koh Phangan Map (major update and additions 2018)

Water Quality Koh Tao Map (new for 2018)

Water Quality Ang Thong National Marine Park (new for 2018)

Around the islands a total of 8 sampling points were taken ...with the exception of one, which had a slightly raised nitrate level, all passed the testing protocols.

Water Quality Phuket Map (updated 2018)

Although using slightly different testing and presentation systems this data is broadly comparable with the Samui and Phangan data.

EcoThailand now have access to the recent inland waterway sampling and analysis undertaken by Dept Environment, Surat Thani.

All sites tested passed specification, with one marginal fail (to be investigated and retested).

Whilst several sites would not be classed as 'pristine' the majority were well within specification limits.

Hopefully future testing can be expanded to include additional sites on the island, to include both random test sites and several which may give cause for concern,

Overall a good result for the island.

Thai government water quality testing standards and procedures


Department of Marine and Coastal Resources (DMCR) has extensive literature and downloadable books and information available HERE

If you find our water quality maps useful, we would appreciate a donation via PayPal to support us in our eco projects within the Gulf of Thailand.

With thanks from the EcoThailand Team

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