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By Samina Chaudhary
ISLAMABAD, Aug 9 (APP): With the right infrastructure and strict enforcement of the Green Building Code, Pakistan could capture over 30 trillion liters (7.9 trillion gallons) of rainwater annually, enough to significantly reduce urban water stress, recharge groundwater, and build resilience against worsening climate impacts.
Experts say the solution is simple, scalable, and already falling from the sky. A modest 1,000 sq. ft. rooftop can collect around 60,000 liters (15,850 gallons) per year with moderate rainfall, sufficient to meet a small household’s basic water needs for several months. Scaled across Pakistan’s vast rooftops, farmlands, and catchment areas, the national rainwater harvesting potential is nothing short of transformative.
Rainwater harvesting has long been a lifeline in Pakistan’s arid regions. In Cholistan, a network of 110 small reservoirs captures 440 million gallons annually, preventing mass migration, livestock losses, and water trucking expenses, saving the national economy nearly Rs. 6 billion per year. In Tharparkar, where water shortages have historically caused high infant mortality and seasonal displacement, rainwater systems, along with saline agriculture and deep wells, are already reshaping local livelihoods.
Now, this traditional rural practice is being transformed into a national policy imperative.
In a landmark move, the federal cabinet has officially approved the Green Building Code of Pakistan (GBCP-2023) along with its Rainwater Harvesting Provisions, making it mandatory for all new residential, commercial, and industrial constructions to install rainwater collection systems.
Integrated into the Pakistan Engineering Council (PEC) Bye-Laws, the policy reflects a shift from voluntary eco-practices to legally enforceable building standards.
From private homes and apartment blocks to shopping malls and factories, all new developments must now include:
Rooftop rainwater harvesting systems
Filtration and underground storage tanks
Green roofs and solar panel integration
Use of eco-friendly, water-efficient construction materials
Design planning with Building Information Modeling (BIM) for water and energy efficiency.
Pakistan ranks among the top 10 countries most vulnerable to climate change and water scarcity. Major cities like Lahore, Karachi, Quetta, and Rawalpindi are losing over 3 feet of groundwater every year.
Just 1 inch of rain on a 1,000 sq. ft. roof can yield 600 gallons of water.
In Islamabad’s 30-inch rainfall, that’s 18,000 gallons a year, per rooftop.
Scale it up to buildings and housing societies, and you’re saving hundreds of thousands of gallons annually.
Across Pakistan’s urban infrastructure, the total national rainwater harvesting potential exceeds 7 trillion gallons annually.
“Rainwater harvesting is not new. What’s new is our urgency,” said Dr. Bashir Ahmed, Director at the Climate Energy & Water Research Institute (CEWRI) talking to APP. “The cabinet’s recent approval gives this practice legal backing, it’s now a matter of implementation at scale”,he suggested its strict enforcement.
Dr. Ejaz Ahmed, an environmental policy expert, speaking to App said, “Urban groundwater is in crisis. The Green Building Code is a blueprint for cities that want to survive the next decade. This policy initiative could become a frontline tool in Pakistan’s fight against worsening climate challenges and growing water scarcity.”
While cabinet approval is a breakthrough, experts emphasize that enforcement, community engagement, and local capacity building are essential for lasting impact. Key next steps include:
Incentives for retrofitting old buildings with rainwater systems
Public education campaigns on water use and system maintenance
Training for architects and engineers on eco-compliant designs
Municipal monitoring to ensure compliance and system upkeep
The newly approved Green Building Code represents more than a change in construction law—it’s a national climate resilience strategy. Pakistan is no longer waiting for solutions from abroad. By investing in homegrown, nature-based solutions like rainwater harvesting, the country is creating a future where every drop is valued, every building contributes, and every citizen plays a role.
Around the world, rainwater harvesting has emerged as a proven solution to water scarcity and climate resilience. In Australia, it is legally required in many new buildings and has helped cities manage prolonged droughts. India’s mandatory rainwater systems in urban areas like Tamil Nadu led to a remarkable rise in groundwater levels within just a few years. Singapore, despite limited land and no natural freshwater sources, captures rain from over two-thirds of its surface area to supplement its national supply. Germany and parts of the United States encourage harvesting through financial incentives, reducing pressure on stormwater systems and lowering water bills.
Because in the face of climate volatility, every drop truly counts