Planning guide
How long does it take to install?
A realistic, phase-by-phase timeline for rooftop solar and rainwater harvesting — for a home or a small business. The short version: solar takes weeks, but the wait is DISCOM approval and metering, not the day or two of physical install. Rainwater harvesting has no approval bottleneck at all.
What are you installing?
For a…
System size
- 1
Site survey, shadow analysis & quote
3–7 days
A vendor checks your roof, shading and sanctioned load, then quotes.
- 2
Portal registration & DISCOM feasibility approval
7–14 days
Systems up to 10 kW skip the separate feasibility step, so approval is quicker.
- 3
Physical installation
1–2 days
Mounting, panels, inverter and wiring — the fast part.
- 4
DISCOM inspection & bidirectional meter
7–21 days
The DISCOM inspects and fits the net (bidirectional) meter.
- 5
Commissioning & net-metering activation
2–5 days
Your export starts offsetting the grid units you draw.
- 6
Subsidy credited to your bank
30–45 daysin the background
The central rooftop-solar subsidy arrives after commissioning — it doesn't delay switch-on.
- These are typical ranges, not a quote — your installer and DISCOM circle set the real dates.
- The subsidy credit lands about a month after commissioning and doesn't delay when your system switches on.
- Rules and timelines change. Last verified 2026-07-08.
A 3 kW home system typically takes 3–7 weeks from survey to switch-on. The panels go up in a day or two — the wait is DISCOM approval and metering.
What actually drives the wait
Solar: approvals, not construction
Portal registration, DISCOM feasibility, then inspection and the bidirectional meter. Systems under your DISCOM's waiver threshold skip the separate feasibility step and move faster.
See the net-metering process →Rainwater harvesting: mostly the digging
A site visit, a short design, then excavation and plumbing. A retrofit needs no approval; for a new building it's tied to your completion / occupancy certificate.
Estimate your harvest →Install timelines — frequently asked
How long does it take to install rooftop solar in India?
A typical home system takes about 3–7 weeks from the first site survey to switch-on. The panels themselves go up in a day or two — most of the wait is DISCOM feasibility approval and the inspection where the bidirectional (net) meter is fitted.
Why does solar take weeks when the panels go up in a day?
Because the timeline is driven by approvals, not construction. You register on the national portal, the DISCOM checks your sanctioned load and feasibility, then after installation it inspects the system and fits a net meter before commissioning. Those approval and inspection waits are the bulk of the calendar time.
Does waiting for the subsidy delay my solar?
No. The central rooftop-solar subsidy is credited to your bank account about a month after commissioning — it arrives after your system is already switched on and generating, so it doesn't hold up the install.
How long does a rainwater-harvesting system take to install?
For a home retrofit, usually about 8–15 days end to end — a site assessment, a short design, and a couple of days of excavation and plumbing. Unlike solar, there's no grid-approval bottleneck. A society or commercial system runs longer, roughly 2–6 weeks, mostly excavation and plumbing.
How long does a commercial or small-business rooftop system take?
Plan for about 5–12 weeks. Larger systems almost always go through the DISCOM's feasibility study on sanctioned load and a longer inspection, and commercial rooftops don't qualify for the residential subsidy — so the timing drivers are approvals and metering rather than any single incentive.