Rainwater Harvesting Systems

Every roof in Maharashtra receives 2,000–3,000 mm of rain in four months. We turn it into stored water, recharged groundwater and a compliance certificate — designed on the numbers, not a standard drawing.

Why rainwater harvesting

Rainwater harvesting (RWH) is mandatory for new buildings above a plot-size threshold under UDCPR Maharashtra and most municipal by-laws, and it is the cheapest water a building will ever get — a 1,000 m² roof in Mumbai yields about 1,800–2,200 m³ a year. Done properly it cuts tanker dependence, recharges the borewell, and reduces flooding load on the plot. Done as a formality, it becomes a blocked pit that fails inspection.

We size collection, first-flush, filtration, storage and recharge from your roof area, rainfall data and soil percolation test — and hand over a system with drawings, a maintenance schedule and the documentation your municipal completion certificate needs.

System elements

Catchment and conveyanceRoof and paved-area drains, gutters and downtakes sized for peak intensity (75–100 mm/h), leaf screens, overflow.
First-flush diverterDiscards the first dirty run-off of each event automatically.
FiltrationGravity or pressure sand/gravel filters, or screen-cartridge units; 5–200 m³/h; backwashable.
StorageUnderground RCC or modular tanks sized against demand and dry-day pattern; disinfection where water is used indoors.
Groundwater rechargeRecharge pits, trenches and bore-recharge wells designed from percolation test; silt traps; monitoring.
Reuse plumbingDual plumbing to flushing, gardening, cooling make-up; UV/chlorination for non-potable indoor use.
DocumentationAs-built drawings, capacity calculation, compliance certificate support for CC/OC.

Where we design RWH

Housing societies and townships: Compliance plus real tanker-cost saving; recharge to society borewells.
Factories and warehouses: Large roofs — 5,000–50,000 m² — with storage feeding process and cooling make-up.
Schools, hospitals, hotels, malls: UDCPR compliance, landscape irrigation, flushing.
Industrial estates and campuses: Storm-water plus recharge planning at estate scale.

Indicative yield

Roof area	Annual rain	Harvestable (80 %)	Tanker-equivalent
500 m²	2,200 mm	~880 m³	~90 tankers of 10 KL
2,000 m²	2,200 mm	~3,500 m³	~350 tankers
10,000 m²	2,200 mm	~17,600 m³	~1,760 tankers

Mumbai-region rainfall; adjust for your station. We compute exact figures from IMD data for your location.

Frequently asked questions

Is rainwater harvesting mandatory?

In Maharashtra, UDCPR requires RWH for plots above a size threshold (commonly 300–500 m² depending on the planning authority) and most municipal corporations check it before completion certificate. Requirements vary by city — we confirm the applicable clause for your plot.

Can harvested rainwater be used for drinking?

With filtration, storage hygiene and disinfection (UV/chlorination) it can meet drinking standards, but most buildings use it for flushing, gardening, cooling make-up and recharge, keeping potable use to treated municipal supply.

How much does an RWH system cost?

A society system with filtration and recharge typically costs a few lakh rupees; large industrial roofs with storage and reuse run higher. The payback against tanker water is usually 2–4 monsoons.

Do you also do groundwater recharge only?

Yes — recharge pits, trenches and bore-recharge wells with silt traps, designed from a percolation test, are a common stand-alone scope.