Hydro Gravitricity

A retrofittable rainwater filtration and monitoring system


Water is a very scarce resource, especially in current times. According to UNICEF water scarcity reports, 50 percent of the world’s population could be living in areas facing water scarcity by as early as 2025 [1]. 135 Liters of water are consumed per day per person in India without laundry or washing as per the Ministry of Housing and Urban Affairs report [2].

600 millionIndians are facing high water scarcity stress right now.

40%of Indians will not have access to drinking water by 2030.

Gated Communities

Modern engineering has made architectures, like gated communities, possible, with multi-storied group apartments with lavish gardens, restaurants, convention halls, and swimming pools. On average, there are about 150 gated communities in Visakhapatnam and 130,000 gated communities in the top 50 cities in India. Many of these gated communities in our city, Visakhapatnam, face a water crisis.

These communities have around 800 flats with 24,000 m2 of land, as big asthree and a half football fields.

To mitigate the shortage, a single gated community pays for water supplies from the municipality, which costs them approximately USD 140,000 (based on 135 liters per day per capita a year consumption according to NITI Aayog report, 4 members in a family on average). Read more here.

The conglomeration of 130,000 gated communities from the top 50 Indian cities takes up a whopping 9.2 trillion liters per year, costing USD 18.2 billion to the 130,000 gated communities.
These communities have a vast area covered; they also have a massive catchment area of 24,000 m2, including rooftops and private pathways. This allows the communities to capture around 1/3rd of the total catchment area amounting up to 7.7 million liters of rainwater/stormwater per year, which is adequate to satisfy the water requirement for cleaning purposes.

Current Scenario

To understand how this precious rainwater is managed in both the recently constructed and existing gated communities, we visited multiple of these in the past few months. Our consequent visits unfolded to use the existing rainwater drainage and storage mechanism of these buildings. Storm drains, which are used to drain the rainwater captured on the roof and pathways, redirect the water to a stormwater sump, an underground tank built solely to store rainwater. The stormwater is then drained out using pumps in the sewer system of the building. It implies that the entire water gets unutilized and mixes with the sewer water. That is a problem, but we went a step ahead and asked why they were draining this water out?

After interviewing many builders, engineers, residents, and maintenance staff, it came out that they are skeptical of the quality and unaware of the quantity of this water, which could have driven them to optimally reuse this water.

Existing Solutions

There are currently no commercial solutions available to address this specific issue, and those that are available are only focused on rainwater storage rather than filtration and monitoring of the water. These systems are quite large and cannot be accommodated within the existing infrastructure. Some of the present rainwater collecting technologies are designed for very small constructions with very limited water demands. Their residual waste contains significant levels of chemical dosage, which has the potential to pollute the environment if not properly managed. In certain cases, these methods result in a higher volume of unfiltered drain water than the amount of filter water required.

Our Solution

A compact device with a retrofittable filtration mechanism and real-time quality and quantity monitoring, Hydro Gravitricity raises awareness and trust in rainwater collecting and reuse by increasing user awareness and confidence. Our system aims to alleviate installation and maintenance hassles while improving product longevity.

Salient features:

Our system can be easily installed into the inlets of a stormwater sump; when rainfall is collected from the drain to the stormwater sump, our system filters and enhances the quality of the water, increasing the trust in the water’s ability to be reused in the future. The filtration unit has a screening mesh and 3 grades of sand vertically stacked in compartments which aid in effective filtration.

Immediately after the following filtration, the pH, TDS, turbidity, and flow are monitored by the sensors in our system.

This information is wirelessly transferred to a dashboard handled by the community’s maintenance personnel. It wirelessly transmits the data to a dashboard operated by the community’s maintenance staff, which allows them to make informed decisions about water usage.

Water usage:

  • Car washing
  • Landscaping
  • Home cleaning


After extensive research and development for a couple of months, we built a miniature prototype with three enclosures:

The Buffer Unit stores the water temporarily to get the quality metrics in real-time.

These quality metrics are wirelessly transferred to a dashboard and alert the users via mobile notifications and dashboard color.

The design for this dashboard transpired from our multiple interactions with the maintenance staff of various gated communities, with valuable feedback each time. The next iteration of our prototype will be easy to fit in existing and newly built neighborhoods, capable of periodically cleaning itself, fine-tuned using sensor data and Machine Learning.

Value Proposition

Business Model


  • Apartment associations: These are the existing gated community owners. Our solution would retrofit into their existing architecture. There are 150 in Visakhapatnam and 130,000 in the Top 50 Indian cities.
  • Builders: Our system would be implemented in the newly planned gated communities or projects undertaken by the builders as this makes the buildings future-proof.
  • Office Complexes: Government or privately-owned office complexes would want to reuse, reduce and recycle (3Rs principle) this rainwater in order to make a transition towards green technology.



Our system can save an average of 4.3 million liters of water per year per gated community. This equates to 6.1 percent of the community’s supplied water, saving them around USD 8,500 annually.

Installing our product will increase awareness of water consumption, indirectly increasing the adoption rate of such sustainable systems amongst the common public. The implementation of a circular economy is at a much faster pace.

If this approach is implemented in India’s top 50 cities, it will save 550 billion liters of water, which translates to USD 1.2 billion.

Aligned with national initiatives like theJal Jeevan Mission.

Contributes to the UNSDGs6– clean water sanitation, 7– Affordable and clean energy, 9– Innovation and infrastructure,11– Sustainable cities and communities, 13– Climate action, 15– Life on land.

Supportsdecrease in CO2 emissionsdue todecreased use of water transportation.



[1] https://www.unicef.org/wash/water-scarcity#:~:text=Half%20of%20the%20world’s%20population,of%20extremely%20high%20water%20stress.