The government is putting drinking water on the special price control list to protect consumers in the face of the drought.
Wiboonlasana Ruamraksa, director-general of the Internal Trade Department, said authorities were closely monitoring the impact of the drought, which has arrived earlier this year.
"The department is including drinking water in the special price control list for daily monitoring this month," she said. "However, consumers can rest assured that the drought will have no impact on the supply of drinking water."
The Metropolitan Waterworks Authority (MWA) earlier urged households in the capital and its vicinity to reserve at least 60 litres of drinking water for the duration of the drought season until May as there will be less water to provide tap water to households in Bangkok, Nonthaburi and Samut Prakan.
According to the MWA, the Chao Phraya River will be at higher risk of salt water intrusion this year as the water volume released from dams will probably drop because of drought conditions, causing problems for tap water production.
However, the authority is confident it will not have to stop supplying tap water to 12 million users including companies and state organisations in the three provinces.
In a move to appease consumers' concerns, the Internal Trade Department will hold a joint meeting with 11 bottled drinking water manufacturers on March 9 to discuss the impact of a possible water shortage.
"As far as the authorities have been monitoring, we have yet to find a drinking water shortage and any irregularities," Ms Wiboonlasana said. "Drinking water purchase may increase during this period because of promotional campaigns launched by department stores, not from hoarding."
In January, the central commission on prices of goods and services maintained price controls on 41 items, unchanged from last year.
The price control list covers essential items for daily use such as food, consumer products, farm-related products (fertilisers, pesticides, animal feed, tractors, rice harvesters), construction materials, paper, petroleum and medicines.
Listed foods include garlic, paddy, milled rice, corn, eggs, cassava, wheat flour, yoghurt, powdered/fresh milk, sugar, vegetable/animal oils and pork.
Consumer products include detergents, sanitary napkins and toilet paper.
Businesses making or selling products on the list are required to inform the authorities of their production costs and seek approval before any price increase.
The Commerce Ministry has 225 items under its supervision, mainly essential products and services including sensitive products that need daily monitoring such as packed rice, cooking oil, eggs, pork and powdered milk.
Singha Corporation assistant vice-president Chatchai Viratyosin said the company had a back-up plan to deal with the drought this year.
"We can comfortably deal with the drought, which is an expected natural problem that has taken place frequently in the past few years," he said.
The company is still confident that the supply of drinking water will not be short this summer. It will impose measures it used last year to solve the shortage of water if it happens.