Black rain in Singapore? What the haze tests actually show

<p><em>Special Reporting from LSN News, adapted from today's Asia Behind the Headlines episode. <a href="https://youtu.be/haB3QZjpjsU" target="_blank" rel="noopener">Watch the video on YouTube.</a></em></p>

<p>More than 350,000 views. That is how far just two posts on X had travelled by Monday morning, both showing pails of rainwater in Singapore turned grey and black during this month's haze. One, from Mothership, described the water as "blackish &amp; filthy". Replies and reposts did the rest: some users called the rain toxic, and others asked whether the city's drinking water was next. The pictures were real. The question is what they actually mean.</p>

<h2>What the tests found</h2>

<p>Singapore's national water agency, PUB, collected samples on 17 October, when the Pollutant Standards Index stood at 193, inside the 101-to-200 band classed as unhealthy. The samples included rainwater from Kranji and Ulu Pandan, run-off from Yew Tee, and tap water.</p>

<p>The haze rain was different. According to figures shown by Singapore's Minister for Sustainability and the Environment, Grace Fu, the rainwater collected that day had a pH of 5.7, against 6.6 for rain during moderate haze and 6.8 on a normal day. It was also cloudier: its turbidity reading of 5.7 was almost three times the normal-day level of 2.1. Treated water measured a pH of 7.8 and turbidity of 0.21.</p>

<p>So the change is real. But it needs context. The United States Environmental Protection Agency notes that normal rain is already slightly acidic, with a pH of about 5.6, because carbon dioxide dissolves in it. By that benchmark, the haze sample was close to ordinary rain. Fu also said that how black the water looked depended on whether it was caught directly from the sky or collected from run-off.</p>

<h2>What it means for the taps</h2>

<p>On drinking water, the minister was direct. "While the blackish water seems worrying, our tap water remains clean and safe to drink," she said in a video filmed at PUB's water quality laboratory on 24 October. She said Singapore's treatment processes can filter out particles up to 100 times smaller than PM2.5, the fine particulate matter that dominates haze, and that PUB had stepped up checks during the haze and found no unusual changes in treated water.</p>

<p>She added a warning that applies with or without haze: collected rainwater should not be used for drinking, cooking or personal hygiene. That is the practical takeaway.</p>

<h2>The regional picture</h2>

<p>The black rain is a Singapore image, but the haze is a regional story. The smoke comes from fires in Indonesia, where, according to Malaysia's Deputy Prime Minister Ahmad Zahid Hamidi, the Indonesian government has deployed more than 16,000 personnel, along with aircraft and firefighting helicopters. He said aerial operations have been hampered by poor visibility.</p>

<p>Malaysia has felt it sharply. In Johor, schools were closed on 7 and 8 October, again from 12 to 16 October and again from 19 to 23 October. On Monday, only students sitting examinations return, with all schools scheduled to reopen on Wednesday, subject to air quality. At 6pm on Sunday, eight Malaysian monitoring stations were still in the unhealthy range, led by Serian in Sarawak at 192. Singapore's National Environment Agency says the risk of transboundary haze continues in areas facing prolonged dry weather.</p>

<p><strong>Our read:</strong> the black rain is a symptom, not the danger. What matters for health is the air people breathe, and the tap water, on the official evidence, is fine. The haze returns every dry season until the fires are stopped at source, and that is a question for governments across Southeast Asia, not for a bucket on a balcony.</p>

<h2>Sources</h2>

<ul>

<li><a href="https://x.com/MothershipSG/status/2110964262252556384" target="_blank" rel="noopener">X post by @MothershipSG, 16 Oct 2026</a></li>

<li><a href="https://x.com/malaymail/status/2111004281843089703" target="_blank" rel="noopener">X post by @malaymail, 16 Oct 2026</a></li>

<li><a href="https://www.straitstimes.com/singapore/singapores-tap-water-still-safe-to-drink-grace-fu" target="_blank" rel="noopener">The Straits Times, 24 Oct 2026 (updated 26 Oct)</a></li>

<li><a href="https://www.channelnewsasia.com/singapore/tap-water-safe-drink-haze-6488996" target="_blank" rel="noopener">CNA, 24 Oct 2026</a></li>

<li><a href="https://www.asiaone.com/singapore/blackish-rainwater-during-haze-drinking-water-safety" target="_blank" rel="noopener">AsiaOne, 25 Oct 2026</a></li>

<li><a href="https://mothership.sg/2026/10/tap-water-safe-drink-haze/" target="_blank" rel="noopener">Mothership, 24 Oct 2026</a></li>

<li><a href="https://www.epa.gov/acidrain/what-acid-rain" target="_blank" rel="noopener">US Environmental Protection Agency, &quot;What is Acid Rain?&quot;</a></li>

<li><a href="https://www.malaymail.com/news/malaysia/2026/10/25/zahid-malaysia-reaffirms-commitment-to-assist-indonesia-in-tackling-transboundary-haze/240515" target="_blank" rel="noopener">Malay Mail / Bernama, 25 Oct 2026 (malaymail.com)</a></li>

<li><a href="https://www.thestar.com.my/news/nation/2026/10/25/haze-only-exam-candidates-to-return-to-school-on-oct-26--27" target="_blank" rel="noopener">The Star, 25 Oct 2026</a></li>

<li><a href="https://www.malaymail.com/news/malaysia/2026/10/25/haze-eight-areas-nationwide-record-unhealthy-api-as-of-6pm-serian-highest-at-192/240573" target="_blank" rel="noopener">Malay Mail / Bernama, 25 Oct 2026 (malaymail.com)</a></li>

<li><a href="https://www.nea.gov.sg/corporate-functions/weather/regional-haze-situation" target="_blank" rel="noopener">National Environment Agency (Singapore), Regional Haze Situation, 25 Oct 2026</a></li>

<li><a href="https://www.businesstoday.com.my/2026/10/25/singapore-air-quality-remains-mixed-as-haze-affects-three-regions/" target="_blank" rel="noopener">BusinessToday (with AFP), 25 Oct 2026</a></li>

</ul>