What is Rain GEO SAT?

Rain GEO SAT is a satellite-powered Water Intelligence Platform built by Amruta Integrated Water Solutions Pvt. Ltd. (Pune, India). It fuses NISAR SAR, GPM IMERG rainfall, Copernicus DEM, SoilGrids hydrogeology, ECMWF ERA5 climate reanalysis, and ISRO Bhuvan layers to design rainwater harvesting systems, groundwater recharge structures, stormwater drainage, and ESG water disclosures. Outputs are calibrated to the exact GPS coordinates of each site and produce engineering designs plus compliance reports for IGBC, LEED, GRIHA, BRSR, GRI 303, CDP, CSR, World Bank ESF, and UN SDG 6/11/13/15.

How does satellite data improve rainwater harvesting design?

Satellite rainfall (GPM IMERG) provides 0.1° / 30-minute global coverage with a 20-year record, enabling statistically robust annual exceedance probability curves. NISAR SAR confirms subsurface soil-moisture acceptance for recharge structures. Copernicus DEM at 30 m drives watershed delineation. SoilGrids supplies infiltration Ksat for SCS Curve Number runoff. Together they replace manual monsoon estimation with site-specific, auditable numbers that hold up in IGBC, LEED, and BRSR review.

Which sustainability frameworks does Rain GEO SAT support?

IGBC, LEED v4 / v4.1 Water Efficiency, GRIHA, BRSR (SEBI Principle 6), GRI 303, CDP Water Security, SASB water intensity, CSR Companies Act 2013 Schedule VII, World Bank ESF water annexes, and UN SDG 6, 11, 13, and 15. All reports are auto-generated from the same satellite-validated project inputs.

How accurate is GPM IMERG rainfall for Indian sites?

GPM IMERG Final Run provides 0.1° / 30-minute global rainfall coverage. For Indian sites, Rain GEO SAT bias-corrects IMERG against IMD AWS ground stations, achieving ±8–12% monthly accuracy. The 20-year IMERG record plus ERA5's 40-year reanalysis enables pre/post-COVID-2020 trend comparison and climate-risk projection used in BRSR and World Bank ESF disclosures.

Who built Rain GEO SAT?

Rain GEO SAT is built by Amruta Integrated Water Solutions Pvt. Ltd. (AIWS), led by MP Reddy, Managing Director & CEO. MP Reddy brings 20+ years of field experience in Hydrogeology and Hydrology, and holds IIT Bombay professional certifications in Rainwater Harvesting, Water Management, and Water Sustenance. He has led water-resource projects across five Indian states and multiple African countries. AIWS grew from the Amruta Group, founded in Hyderabad in 1990, and today operates across Hyderabad, Pune, Mumbai, and Bengaluru — with a specialist team of Hydrogeology and Hydrology professionals and 35 years of continuous water-engineering practice behind every Rain GEO SAT report.

What outputs does the Expert tier produce?

The Expert tier outputs full scientific RWH designs: multi-source rainfall fusion (NASA POWER, Open-Meteo, IMD, ERA5), DEM-based catchment delineation, NDVI vegetation indexing, hydrogeology parameters from SoilGrids + Bhuvan, CGWB-compliant recharge-pit and borewell-recharge geometry, SCS-CN runoff and peak discharge for drains, and ESG/BRSR/World Bank-ready PDF reports with satellite-validated rainfall baselines and 40-year climate trend overlays.

How do I design a rainwater harvesting system for a building in India?

To design a rainwater harvesting system in India, calculate annual yield: Catchment Area (m²) × Annual Rainfall (mm) × Runoff Coefficient (0.75–0.90 by roof type). Size the storage tank for peak demand months with first-flush diversion of 2 mm per event. For groundwater recharge, follow CGWB Master Plan (2020) — 1 m³ recharge pit per 25 m² catchment, adjusted for local SoilGrids infiltration rate. Rain GEO SAT automates this using satellite rainfall and soil data for your exact GPS coordinates.

What is the CGWA NOC requirement for groundwater extraction in India?

Under the Environment (Protection) Act 1986, any industrial project extracting groundwater above 10 m³/day requires a No Objection Certificate from the Central Ground Water Authority (CGWA NOC). The Bhu-Neer / NOCAP portal requires a hydrogeological report, rainwater harvesting and recharge plan, water balance chart, and geospatial site demarcation. Rain GEO SAT Professional and Expert modes generate satellite-evidenced CGWA NOC documentation for all six mandatory components.

Which satellite data is used for rainwater harvesting design in India?

Rain GEO SAT fuses nine satellite and climate sources: NASA/ISRO NISAR L-band SAR (soil moisture), ISRO Bhuvan (India terrain), NASA GPM IMERG (0.1°/30-min precipitation), Copernicus DEM (30 m elevation), ISRIC SoilGrids (infiltration Ksat), ECMWF ERA5 (40-year climate), Copernicus EFAS (flood alerts), Open-Meteo and Meteostat (station data), and IMD AWS (India bias-correction). All sources maintained by NASA, ISRO, ESA, ECMWF, or ISRIC — reports are defensible to IGBC, LEED, GRIHA, BRSR, and CGWA regulators.

What is water positive certification and how does a building qualify in India?

Water positive certification India means a building replenishes more water than it consumes — typically verified by GRIHA or CII-GBC under the IGBC Net Zero Water Rating. To qualify, a building must demonstrate a positive water balance: total groundwater recharge plus rainwater harvested must exceed total freshwater consumption. ISO 46001 water management system alignment and BRSR Principle 6 disclosure support the certification pathway. Rain GEO SAT Expert mode generates the satellite-verified water balance evidence required for water positive certification.

What is Zero Liquid Discharge and is it mandatory in India?

Zero Liquid Discharge (ZLD) means a facility recovers and reuses all process wastewater with no liquid effluent discharged to the environment. Under CPCB guidelines, ZLD is mandatory for textiles, distilleries, pharma, chemicals, and power generation sectors as a condition of their Consent to Operate or Environmental Clearance. ZLD systems typically recover 90–95% of wastewater for reuse, reducing freshwater dependency by 80% or more. When combined with a rainwater harvesting system and groundwater recharge design, ZLD enables full water circularity and supports water neutrality certification.

What is net zero water and how does it differ from water positive?

Net zero water means an organisation withdraws no more water from the natural environment than it returns at equivalent quality in the same watershed. Water positive certification India goes further — the organisation actively replenishes more water than it consumes, contributing to watershed restoration. Rain GEO SAT Expert mode supports both pathways by quantifying groundwater recharge volumes from satellite-verified SoilGrids infiltration and NISAR SAR soil moisture, generating the water balance evidence required for BRSR Principle 6, GRI 303, and CDP water security questionnaire disclosures.

How does rainwater harvesting support BRSR water disclosure in India?

BRSR (Business Responsibility and Sustainability Report), mandated by SEBI for India's top 1,000 listed companies, requires quantified water withdrawal, consumption, recycling, and recharge disclosures under Principle 6. A rainwater harvesting system reduces freshwater withdrawal and increases the water recycling ratio — both key BRSR metrics. Rain GEO SAT auto-generates BRSR water disclosure reports with satellite-verified rainfall baselines, catchment yield, recharge volumes, and 40-year ERA5 climate risk overlays — aligned with GRI 303 and CDP water security questionnaire schemas.

How much water can a 1000 sq ft roof harvest?

Approximately 76,000 litres per year at 1000 mm annual rainfall (1000 sq ft ≈ 93 m² × 1000 mm × 0.85 runoff coefficient / 1000 = 79 kL, minus first-flush and evaporation losses).

Is this calculator suitable for regulatory submissions?

The Professional and Expert modes generate reports aligned with IS 15797:2008, CGWB Master Plan (2020), and CPHEEO manual formulas. Municipal corporations in Bengaluru, Chennai, Hyderabad, and Pune have accepted these formats.

Does the tool work outside India?

Yes. Rainfall is sourced from NASA POWER, Open-Meteo, and Meteostat globally. IMD is used inside India for the highest resolution.

Rain GEO SAT

Satellite Rainwater Harvesting Intelligence

Rainwater Harvesting Calculator: Rooftop Yield, Tank Volume & Recharge Sizing

The Rain GEO SAT rainwater harvesting calculator estimates annual rooftop yield in litres, sizes storage tanks against demand, and recommends recharge structures using site-specific rainfall from IMD, NASA POWER, Open-Meteo, and Meteostat. It follows IS 15797, CGWB Master Plan (2020), and CPHEEO manual conventions used by consulting engineers in India.

Run a free rooftop calculation →

How the yield formula works

Annual harvestable volume V (litres) = Catchment Area (m²) × Annual Rainfall (mm) × Runoff Coefficient. For an RCC rooftop with runoff coefficient 0.85, a 200 m² roof in a 900 mm rainfall zone yields 200 × 900 × 0.85 = 153,000 litres per year.

The platform corrects for first-flush diversion (typically 2 mm per rain event), evaporation from open tanks, and monthly rainfall distribution so the storage tank is not oversized for a single peak month.

Inputs the calculator needs

You provide catchment area, roof material, location, and household or building demand. Rainfall, soil, and elevation are auto-filled from remote sensing sources.

Rooftop area in m² (or ft², auto-converted)
Roof material — RCC (0.85), GI sheet (0.90), tiled (0.75), garden roof (0.35)
Location — auto-detected coordinates for rainfall lookup
Daily demand in litres per capita per day (LPCD)
Preferred use — direct use, storage + use, or recharge

Storage tank vs recharge structure — which one?

Storage tanks work when rainfall is well distributed and demand is continuous. In cities like Bengaluru and Chennai the platform typically recommends 5,000–20,000 L tanks for residential rooftops.

Recharge structures (pits, trenches, borewell recharge) are recommended where the water table is depleting, roof area is small, or piped supply is reliable. The Expert engine sizes recharge pits per CGWB norms — 1 m³ pit for every 25 m² of catchment as a rule of thumb, adjusted for local soil infiltration rate.

Frequently asked questions

How much water can a 1000 sq ft roof harvest?: Approximately 76,000 litres per year at 1000 mm annual rainfall (1000 sq ft ≈ 93 m² × 1000 mm × 0.85 runoff coefficient / 1000 = 79 kL, minus first-flush and evaporation losses).
Is this calculator suitable for regulatory submissions?: The Professional and Expert modes generate reports aligned with IS 15797:2008, CGWB Master Plan (2020), and CPHEEO manual formulas. Municipal corporations in Bengaluru, Chennai, Hyderabad, and Pune have accepted these formats.
Does the tool work outside India?: Yes. Rainfall is sourced from NASA POWER, Open-Meteo, and Meteostat globally. IMD is used inside India for the highest resolution.

Ready to apply this on your site?

Rain GEO SAT calculators use IMD, NASA POWER, Open-Meteo, and CGWB data to deliver engineer-grade rainwater harvesting and groundwater recharge designs.

Basic Calculator Professional Expert Workspace