Karachi. It may have rained in Karachi a few days ago, but people across the city still have to make desperate phone calls to order water tankers because piped supplies don’t reach their homes. In Quetta the water shortage is so bad that the ground has started to subside or sink because the soil has dried up with the lowering of the water table. Houses are developing cracks as a result. And as fears of water scarcities growing people are, however, trying to come up with ways to store water. One trick is rainwater harvesting at home that only costs up to Rs1,500.

“A lot of water is wasted after rainfall and it could be used to serve many people,” said Zafar Iqbal, who is an Islamabad-based professor. Iqbal teaches computer science at the University of Punjab’s Islamabad campus and runs an NGO called WeFixers that works on spreading climate change information.

“I came across this phenomenon on the internet,” he explained. “When I watched a video about rainwater harvesting at home, I immediately thought to give it a try.”

Rainwater harvesting is collecting and storing rain, rather than allowing it to run off into the drain. Rainwater is collected from a roof-like surface and redirected to a tank or a deep pit such as a well or borehole.

“I went to the shop and bought the equipment and to my surprise it only cost me Rs1,500,” said Iqbal. You need a large pit and some industrial pipes to channel the water to and from the pit.

Get cotton, sand, rocks and charcoal to create the filter. “The drain from the roof is connected to the pit where layers of cotton, sand, charcoal and rocks are piled one upon each other to filter out the dirt,” said Iqbal.

According to Iqbal, for the past few years, Islamabad has been facing a severe water shortage. Tanker rates are going up (one tanker lasts a week and costs Rs5,000). The tankers come from far away which leads to delays. As a result families spend days without water.

“Boring provides some respite in such cases but in 2020, the boring water dried up too,” said Iqbal. “Rainwater harvesting provides a reliable clean flow of water for some days.” It also rains a lot more in Islamabad.

According to Iqbal’s estimate, from last week’s rains in the capital, he was able to gather enough water that saved him around Rs10,000. “My friends also use this technique in their houses,” he said. “The video that we shared on our Twitter handle is my friend’s.”

Villages use different techniques to store rainwater.

According to the Pakistan Council of Research in Water Resources, Pakistan is using rainwater harvesting on a national level. A network of rainwater harvesting systems has been developed on 26,000 sq km in the Cholistan desert by developing 110 reservoirs with a capacity to store 440 million gallons.

Twenty deep tubewells have been installed with an annual discharge of about 1,405 million gallons. They become a source of groundwater that can be used for drinking and for animals.

Rainwater harvesting has saved Pakistan Rs6 billions annually.

“My advice for those who use this technique is to clean their roofs first before channeling water through the filter,” said Iqbal. “Secondly, if available, use a plastic sheet on the roof. It will give you cleaner and dust free water.”

The only problem you will face, he said, is that the water comes through the filter slowly.

According to the Pakistan Institute of Development Economics, Pakistan wastes one-third of its available water. This has taken our country’s water availability down from 5,229 cubic meters per person in 1962 to just 1,187 in 2017.

In such a scenario, it may be well worth it to explore cheap solutions such as rainwater harvesting.