Pune and Pimpri Chinchwad's Rivers and Groundwater Threatened by Defunct STPs
Pune and Pimpri Chinchwad are grappling with a significant water crisis, exacerbated by the failure of many residential societies to maintain their sewage treatment plants (STPs). The deteriorated health of rivers winding through these cities has been a recurring issue, with pollution levels reaching alarming levels. Citizens, activists, and experts agree that the lack of efficient STPs is a major contributor to this problem.
A Bombay High Court order on January 19 this year, following a public interest litigation (PIL), directed all municipal corporations statewide to ensure that occupancy certificates (OC) are not given for high-rises unconnected to the civic body's sewage lines or without an STP on their premises. This decision is particularly relevant to Pune, where rapid redevelopment is leading to the construction of new housing societies every day, and access to clean water is becoming an urgent concern.
Incidents like the Guillain-Barré Syndrome (GBS) outbreak in Pune last year, caused by contaminated drinking water, highlight the need to streamline sewage systems to prevent public health emergencies. Far back in February 2024, residents of Blue Ridge, a township of around 20,000 residents in Hinjewadi, were alarmed to find bloodworms (chironomid larvae) in their drinking water. The society lifts water directly from the Mula river, which is continually polluted by sewage from upstream neighborhoods.
When residents complained to the Maharashtra Pollution Control Board (MPCB) and Maharashtra Industries Development Corporation (MIDC), it was found that the contamination was due to the direct dumping of untreated sewage into the river. Officials moved the pipe from which sewage was entering the river away from the society's inlet source, temporarily resolving the issue. However, the problem was not isolated to this one point.
Vijay Patil, a former committee member of the township and part of the team coordinating with officials, explained, “There are a lot of smaller population settlements upstream from us, and since those areas are rapidly developing, there are multiple labor camps there too, which have no other outlet for the sewage generated by occupants. There is also agricultural land on both sides of the river, which gets polluted by the constant use of fertilizers. We have long been victims of this pollution, and since we use this water for drinking and other utilities, the fear of disease looms large.”
The Blue Ridge township is strict with its STP compliances, knowing the consequences of releasing untreated sewage. The treated water from the Blue Ridge STP that is not used by residents is used to water the golf course on the premises. The township has also written to the Pune Metropolitan Regional Development Authority (PMRDA) and MIDC to provide residents with an alternative source of drinking water, considering the short- and long-term effects of using contaminated water.
Unfortunately, cases of untreated effluents polluting groundwater or sewage networks unconnected to a main line are still abundant in the city. As the state nodal agency, MPCB has set up 294 Water Quality Monitoring Stations across Maharashtra. According to a 2023-24 report published by the board, the quality of groundwater mapped at six stations in Pune painted a disturbing picture. Of these, only two recorded ‘good water’ (non-polluted); one recorded ‘poor water’ (polluted); and three were ‘unsuitable for drinking’ (heavily polluted).
At Casa Imperia Phase 1 in Wakad, society chairman Nitin Selute said sewage from nearby areas, especially upstream, has contaminated the only well they have on their premises, which used to be their main source of water. “There is a nullah on the side of our society that was once a stream. The sewage from this nullah started seeping into the well on our premises. We tried treating the water and using it, but it was so dirty that even our STP couldn't handle the load. Eventually, our flush tank also started stinking. For our safety, we stopped using the well and now are entirely reliant on water tankers. We spend Rs 24-26 lakh annually on just domestic and drinking water for 160 flats, which is 40-45% of our budget,” Selute told TOI.
“We live in constant fear of getting sick. It is the civic body's responsibility to provide water to all or ensure that there are clean sources for us to lift from. If permission is given for so many buildings to come up, amenities to cater to them must also be available. There is also a lack of awareness about how our actions affect others. Ensuring accountability from societies, builders, citizens, and civic body departments must be mandated,” he added.
For now, society members are engaged in raising awareness in internal groups about conserving water. Their situation is less than ideal despite their fully functional 100 kiloliters/day (KLD) STP being utilized to its maximum potential. Treated water is used for flushing, ensuring 100% reuse of wastewater generated on the premises, with no existing outlet for discharging it outside the society. The STP undergoes monthly PCMC inspections, too. The society is also taking the guidance of Mission Groundwater, a city-based initiative promoting sustainability in groundwater resources.
Casa Imperia Phase 1 residents also plan to submit a letter to all authorities concerned to help them revive the stream next door, including MPCB and Pimpri Chinchwad Municipal Corporation (PCMC). Mission Groundwater founder Ravindra Sinha told TOI, “Pune and Pimpri Chinchwad combined have around 1,000 private STPs in residential and commercial buildings. Most of these are functional, which is good. Many societies use treated water for flushing and some for gardening. Despite this, most of it gets discharged either into a sewage line on its way to the municipal STP or directly into a stream or river.”
Sinha highlighted, “This is because many buildings also have defunct STPs. Since there are no regular inspections or penal actions taken by authorities, such societies face no repercussions. Further, the cost of running an STP is high, which is a deterrent for many. However, there is a lower Maharashtra State Electricity Distribution Company Ltd (MSEDCL) tariff plan that can be availed. It is also applicable for water treatment plants (WTPs).”
According to Pradeep Pawar, who runs the Shree Water Tech wastewater and sewage treatment company in Wakad, lack of awareness on the importance of having a functional STP in one’s society is the biggest issue across areas. “It is imperative that every society's STP is not just functional but also well-maintained. Some try to circumvent this process because of high running or electricity costs, but that is absolutely wrong. There is also a lot of misinformation. Many opt for maintenance or daily operations to be run by someone local to save money. However, they might not necessarily have the right knowledge, which in turn will cost the society more than needed,” said Pawar, a chemical engineer.
“The size or cost of running an STP depends on the required capacity, which relies on the number of people living in a society. In many cases, the treated water is required to be released back into the drainage lines as the volume of incoming water is always higher than what can be used for flushing or gardening,” he further said. “Ultimately, government authorities, municipal corporations, and residents all need to work in tandem if the issue of untreated sewage entering rivers is to be truly addressed,” Pawar added.
According to UDCPR 2020, all new societies with more than 100 flats are required to reuse grey water after treating it. However, most are unaware of the difference between grey water (showers, laundry, etc.) and black water (toilets, etc.) STPs. Since the latter is a lot more difficult to treat, the costs also run high. At PMC, we have formed a committee chaired by the additional commissioner, of which I am the member-secretary, with other officers and two representatives from two builder associations on board. We have had three or four meetings till date and are taking builder issues and challenges into consideration, too. While almost 80% of societies have functional STPs in PMC limits, they are unfortunately not being used for a number of reasons. We are now exploring a software option for real-time monitoring of STPs. As far as areas on the periphery are concerned, the sewage network itself is missing there, and we have a master plan for the same — Jagdish Khanore, Chief Engineer, Drainage Department, PMC.
We have given notices for non-operational STPs to around 84 societies till date. Many don't run STPs due to high costs, smell, or simply because they don't want to take responsibility. In some cases, clashes between builders and society residents over handover have also rendered STPs non-functional. There are a few unofficial connections to drainage lines as well, which we are investigating. We already have a 16,000km drainage network and will be extending this by 285km, for which a master plan has been created. It also includes some modifications to the old network line. We have a third-party panel consulting with us and have formed a squad of over 300 staff for regular checks in societies. They collect samples and send them for testing to ensure that STPs are functioning correctly. If any lacunae are found, we first send them a notice; if the situation is not remedied, we cut the water connection for infringement of rules — Sanjay Kulkarni, Chief Engineer, Drainage Department, PCMC.
A petition was filed in the National Green Tribunal (NGT) after the 2025 GBS crisis, when contaminated groundwater led to many citizens falling severely sick and some having permanent health problems. During this time, several water samples tested from RO plants, private vendors, and municipal sources in Pune and Pimpri Chinchwad areas showed unsafe contamination well above permissible limits, with coliforms and E. coli detected. The petition in NGT highlighted these environmental and public health hazards, urging immediate intervention to ensure clean water supply, periodic quality monitoring, identification, and elimination of contamination sources, and accountability of civic authorities and water management systems.
