Metropolitant Water Work Authority announced that, with a reduced fresh water coming to the lower Chao Phraya River basin in the dry season, sea water has pushed deeper into the river, reaching Pathum Thani and Bangsai in Ayutthaya. Now the raw water that they use to provide water supply to Bangkok from that area has a rather higher chloride level of 250-260 mg/liter, compare to the usual level of 20 mg/liter.
For normal people, water with higher salt content would not have an adversed health effect, although it might not quench the thirst well. However, people with kidney problem will be affected, and should use water which pass through reverse osmosis. The taste of the water for the next 2-3 months might be a bit different but quality would still be in line with WHO standard.
Area in Thonburi which receive water supply from Mahasawas canel would not be affected.
Ref: Daily News