Inside a white metal cabin beside Gate 2 of Gulmohar Park, residents have begun reading numbers they never expected to care about.The readings appeared on June 11 on a newly installed online water analyser that continuously monitors the quality of water entering one of South Delhi’s most affluent societies before it reaches homes.Installed after a three-week contamination scare, the Delhi Jal Board is testing the system in Gulmohar Park before deciding on a wider rollout.The analyser tracks key indicators: whether the water is too acidic, whether enough disinfectant remains to help keep it safe, and how clear it is.Read | Posh Delhi colony gets sewage in taps: How urban water systems fail, what needs to changeFor residents, those readings have become more than data. They have become a way to measure whether normalcy is returning.Just weeks earlier, many had stopped trusting the water coming from their taps. A newly installed water analyser. (Express photo by Praveen Khanna)Across parts of South Delhi — including Gulmohar Park, Hauz Khas, Sarvodaya Enclave, and Green Park — residents say this summer exposed a troubling reality: a deteriorating water and sewer system alongside recurring seasonal shortages.Story continues below this adBehind incidents of foul-smelling tap water, sewage contamination, and weeks of flushing operations, residents point to an ageing underground network strained by construction activity, rising demand, overloaded sewers, and utility maps that, in some areas, no longer exist.Read | Yamuna level low, water woes in Delhi to continue despite increase in supply from Haryana“This entire saga started somewhere around May 22,” recalled Atul Bal, president of the Gulmohar Park RWA.Some residents said the water smelled foul. Others described murky supply. Families reported falling sick. WhatsApp groups filled with photographs of contaminated water and questions no one seemed able to answer: Was the contamination coming from inside the colony? From outside?Officials spent days tracing possible sources.Bal said one suspected point emerged near B Block, where houses under construction had temporary toilets allegedly positioned above a water pipeline. The structures were removed. Attention then shifted to Gate 2, where Delhi Jal Board teams dug up the area and found a punctured pipe.But the problem did not disappear.Story continues below this adResidents said contamination continued to move through the colony’s ageing internal network for nearly two weeks.Read | Crisis worsens at Delhi’s Gulmohar Park, water contamination spreads across several lanes“Since contamination existed for almost two weeks across the pipeline in the colony, which is almost 60 years old now, residual contamination was still there,” Bal said.The colony eventually began flushing pipelines from the tail end to push out what remained inside, Bal said.After weeks of disruption, the answer was continuous monitoring.For residents, the analyser offers reassurance. But it also raises a larger question.Story continues below this ad A resident of Hauz Khas shows his water tank. (Express photo by Praveen Khanna)****For Gulmohar Park residents, the three week disruption extended beyond bad-smelling water. The daily-life toll was significant, the residents said. Several among them missed work because of illness, some spent money on treatment and tank cleaning, and others paid for private water. “Overall the quality of life had gone down,” Bal said.Vimal Bhan, vice-president of the RWA, said his own health deteriorated during the episode. “It was a health scare. My wife and several other neighbours also fell sick,” he said.Read | ‘Smells like sewage’: Gulmohar Park residents in Delhi complain of water contamination, illnessesLow pressure created another problem. Bhan said household pumps began pulling harder and damaging ferrules. “When the pressure was low, my pump pulled and the ferrules got damaged,” he recalls.Story continues below this adSeveral residents eventually dug up their own service lines and replaced ferrules before realising some of the remaining issues lay within household connections.The colony also had to run a parallel water-supply operation while repairs were underway, the residents said.Bal said the RWA coordinated with DJB for tankers “It was a mammoth exercise – a colony of 700 houses, most of them asking for water,” he said. At one stage, 13 tankers operated in shifts, making around 30–35 trips carrying 10,000 litres each.But even that did not reach everyone. Some residents bought private tanker water, especially those dependent on overhead tanks or unwilling to return to piped supply.********Story continues below this adA few kilometres away, in Hauz Khas Village’s Y Block, amid the simmering mid-June heat, the crisis remained visible in trenches and exposed service lines as workers replaced old pipes.Standing near the dug-up stretch, Prakash Chand Gupta, a Y Block resident, described what had been coming through the taps.“Nalla ka paani aata hai, ek dam kala. (Sewage-mixed water comes in, completely black.) It has been ten days.”His family had been arranging drinking water separately.“This work has been going on for four days now,” he said, expressing hope that repairs would bring relief. “Mostly by this evening… it will get fixed…”Story continues below this adResidents estimated that around 200 people in the area had faced water contamination issues this summer.Nearby, Manoranjan Singh, chief of the federation of RWAs in Hauz Khas, pointed to the underground tank at his house.“Look… you can’t see the bottom. It is so dirty. Earlier it wasn’t like this at all. We could clearly see the bottom.”Residents linked the crisis to ageing infrastructure, intermittent supply and low pressure. Gaurav Sharma, secretary of the RWA of Geeta Bhavan Lane in Hauz Khas, explained that empty pipelines can become vulnerable to contamination.Story continues below this ad“When the water stops, there’s no water in the pipeline,” he said.If sewage accumulates nearby, he said, contaminated water can enter through weak points.“When fresh water comes from behind, it pushes all that sewage into the next few houses.”Singh argued that uneven demand and erratic supply had worsened the situation.“There is no checking nor limits imposed. By the time heavy demands of the first few residences are met, the tail-end houses get really poor supply. The erratic timings of the water supply has been another concern,” he said.*****In Sarvodaya Enclave, RWA head Shaffali Mittal said a similar episode surfaced in the first week of May at the end of one lane, affecting around 10 houses.Before residents realised the scale of the issue, she said, some had already suffered diarrhoea.“We wouldn’t have ever known,” Mittal said.“One person wrote that the water is smelly. Then the entire group started speaking up.”DJB teams later dug up the pipeline and found a fault.“Pipes have gotten old. They are corroding,” Mittal said, adding that the affected section was replaced.But the repairs exposed another concern.“They kept asking us for maps,” she said.“There is no plan. Our colony is like a 60-year-old colony.”Mittal said sewer pipelines had come under growing pressure over the years. “Another major problem nobody is talking about is builders,” she said.She pointed to makeshift toilets at construction sites, waste dumped into drains and polishing residue entering sewer lines. “On ground the problem is so visible. Every colony where big constructions are going on, the lane there faces sewer blockage problems. Eventually there are complaints of bad water,” she alleged.In Green Park, the immediate concern has been water shortage.RWA head Neha Puri said two blocks had received inadequate water supply for nearly 20 days, with the disruption still continuing.“My own family is also affected,” Puri said. “I am currently abroad, but I have had to arrange drinking water for my ageing parents back home.”On June 6, Municipal Corporation of Delhi issued an advisory for under-construction buildings in Green Park: that no damage be caused to sewer lines, water lines, prohibited labour huts and barred construction material from being stacked on roads.The Deer Park booster station serves as a key distribution node for Green Park through supply from Haiderpur Water Treatment Plant. Officials said that this summer, falling water levels at Wazirabad reduced production at critical treatment plants by around 40%, worsening both supply shortages and water-quality concerns.