ULU TIRAM: On that hot, sunny Wednesday morning, the Church of Holy Family in Ulu Tiram, Johor, stands mostly empty, the parking lot devoid of cars. A notice out front declares a fund-raising effort to raise money to build a new church to replace the current 54-year-old building.
Behind the church are the toilets. Turning a tap on, the water comes out in a trickle before strengthening into a moderate stream.
"Sometimes the pressure is low, sometimes it’s okay,” church staff Jane Kaur told Bernama. Water here, she added, has always been a problem.
What worries her now is that the water may stop altogether with the opening of a data centre by Singapore-based Bridge Data Centres (BDC), about 10km away from the church. Data centres are massive consumers of both water and energy.
Johor is fast becoming a data centre hub in Southeast Asia, benefitting from its proximity to Singapore, as well as its land mass, and stable energy sources and water supply.
With the data centre boom and foreign capital flowing into Johor, criticisms and fears over resources have also grown. Data centres require millions of litres of water per day to cool their servers, and residents are worried they will lose their clean water supply. Experts have called for data centres to tap into alternative water sources.
Forty-two kilometres southwesterly from Jane, Ramli Paiman sits at a local restaurant in Gelang Patah, drinking tea. Other than worries about the water supply in their respective areas, what connects these two individuals is a network of pipes and wastewater.
In February this year, Ramli led residents in a protest against the building of a data centre in his locality by Computility Technology, the Malaysian arm of ZData Group. One of their main concerns was whether the data centre was going to siphon all their drinking water to cool down their servers.
The man sitting at the table looks more like a kindly grandfather than a firebrand. His remarks to Bernama also differed from those he made five months ago when he led the protest.
"I’m not worried about the water in this area now. I’ve been told by ZData that they are using recycled water... wastewater,” he said.
Data centres need a lot of water - think millions of litres of water daily - to keep computer chips from melting down. Cool water is pumped in, which cools down the chips by absorbing the heat, and then discharged as hot water. The water must also be clean so as not to contaminate or corrode the equipment.
US watchdog organisation for data centres, Ceres, estimates that each data facility can use up to two million litres of water a day for cooling.
Experts have said that Johor does not have enough clean water to cool the data centres located in the state, on top of meeting the needs of residents and industries.
Charles Santiago, former National Water Services Commission (SPAN) chairman, told Bernama via Google Meet that it is putting a major strain on the existing water system.
"81% of our drinking water (nationwide) comes from rivers. And most of the water now going into all the different data centres in Johor, by and large, are coming from rivers through the (Johor) treatment plants run by SAJ (Ranhill SAJ Sdn Bhd),” he said.
Cognisant of these issues, Johor and the federal government are investing RM5bil into building three reservoirs and three water treatment plants in Johor.
Currently, Ranhill SAJ runs 47 treatment plants capable of producing 2,352 million litres of water per day. Late last year, Johor announced they will no longer approve less-efficient Tier 1 and Tier 2 data centres. It also highly recommends the use of alternative water sources to cool data centres.
Furthermore, on July 16, the Dewan Rakyat was told that new data centres will only be approved if energy and water supplies are sufficient. Deputy Investment, Trade and Industry Minister Sim Tze Tzin also said that domestic consumers would remain the first priority for water supply.
In September 2025, SPAN published guidelines for data centres to use alternative sources of water. The guidelines prioritise using reclaimed water for cooling if it is available, or installing air-cooled systems with zero discharge.
"The issue of reclaimed water is something that's important, given that most of our data centres are using potable drinking water for the cooling of their servers,” said Santiago.
The data centres in Johor are now building their own water treatment plants to siphon clean water into their facilities.
Two of them - BDC and ZData/Computility Technology - use water from Malaysia’s wastewater and sanitation company Indah Water Konsortium (IWK).
The BDC water treatment plant, using patented membrane-tech similar to NEWater, and reverse osmosis, opened in Ulu Tiram in August last year. The ZData/Computility Technology data centre’s water treatment plant opened in March 2026 in Gelang Patah. Both are connected to the same network of effluent water.
A third data centre, DayOne, is drawing and treating raw water from Sungai Tebrau for its facility in Kempas under an agreement with state government-owned company Johor Special Water (JSW), while a fourth data centre AirTrunk’s water treatment plant has not started operations.
How it works
Bernama recently went for a site visit at the BDC water treatment plant in Ulu Tiram, which prohibits recordings of the plant or technology used.
At this treatment plant, wastewater is funnelled from the IWK sewage treatment tank, located about six kilometres away. It goes through the equalisation tank, which, the BDC treatment plant manager told Bernama, is to ensure all incoming wastewater has the same standards, such as temperature, pH and oxygen levels.
Later, the wastewater goes through the anoxic tank, then the oxidation tank, before going through the membrane bioreactor, where the wastewater is refined and filtered several times before going through reverse osmosis.
The leftover waste produced during the refining and filtering process, called sludge, is funnelled into the sludge concentration tank, where staff analyse the content for disposal.
BDC uses the expertise of Suntar International, a Singaporean membrane technology company, to filter the water and reduce contaminants.
"The membrane bioreactor is a globally accepted system and is an upgrade to the conventional activated sludge system, which relies on gravity and time (and a large land footprint) to allow sludge to settle. This improves the water quality,” commented water engineer Datuk Nor Hisham Mohd Ghazali, former chairman of Malaysian Water Partnership, a non-governmental organisation. Nor Hisham is not involved with BDC.
In the reverse osmosis room, the treated water is clean enough for washing hands, which Bernama did, and to take a shower, which Bernama did not. The BDC manager said the water, however, is not for drinking, adding that he would not risk it even if it is boiled.
After reverse osmosis, the water flows into a permeate tank before being piped to the data centre. After use, the water - which is still clean - is flushed into the river. (Sections 21, 24, 25 and 51 of the Environmental Quality Act 1974 require any industrial water discharged into rivers to meet certain quality standards and the temperature to be under 40 degrees Celsius to ensure the health of the river and aquatic life.)
In an email response to Bernama, BDC said before discharging the water into the river, "the water is cooled through the cooling tower process itself” and released at room temperature”.
"An online water quality monitoring device is installed at the equipment discharge outlet to ensure the water quality remains within discharge standards at all times,” it added.
Possible risks
Data centres in Malaysia are not the first to use reclaimed water to cool their system. While this method is more sustainable, it has not always been smooth sailing.
In January this year, a data centre attached to Meta introduced a rare bacterium to the sewage discharge in Cheyenne, Wyoming, in the United States, when the centre flushed its water system. Nor Hisham acknowledged that a similar incident could happen in Malaysia.
"Bacteria are all around us … It can happen in Malaysia, so you need protocols for DOE (Department of Environment) testing of data centre water cooling systems to reduce that risk,” said Nor Hisham, adding that current guidelines on effluents discharged into rivers are applicable to all industries and not specific to data centres.
In its email to Bernama, BDC said its staff conducts routine water sampling tests to confirm that the water being released into the river meets local environmental laws and guidelines.
As for ZData, it said in a statement to Bernama that they operate an "in-house water quality laboratory that conducts regular testing of discharged water”.
The wastewater from IWK is only for BDC’s Ulu Tiram site, as its data centre in Sedenak Tech Park has a freshwater source, according to BDC staff. According to a news report by Water and Waste Water Asia [https://waterwastewaterasia.com/higher-costs-tighter-rules-johors-data-centres-turn-to-reclaimed-water/], BDC’s water treatment plant currently processes five million litres daily, with plans to expand to 20 million litres as demand grows.
Bernama also visited the Computility Technology data centre in Gelang Patah, which uses a more conventional water treatment method by Ocned Water Technology.
Computility Technology director Yeo Yong Hwang told Bernama that they were planning to have four water treatment plants. The current treatment plant processes four million litres of water per day for the data center.
He added that using reclaimed water was part of the company’s green goals.
"We don't need to compete with each other to use the potable water,” he said. "We use 100% reclaimed water.”
No longer worried about water, Ramli now hopes that local residents will be given priority for job opportunities.
"I’ve talked to him (Yeo). I told him, ‘If possible, Mr Yeo, short-term or long-term, please consider giving a chance to our youths here’,” he said. - Bernama
