KUSUM Solar Pump Size by Borewell Depth 2026 Guide

The single most expensive mistake a KUSUM (Kisan Urja Suraksha evam Utthaan Mahabhiyan) applicant makes is choosing the wrong pump horsepower (HP) for their borewell depth. Pick a 3 HP pump for a 180-foot borewell and the water column never lifts to the surface; pick a 10 HP pump for a 50-foot shallow well and the subsidy ceiling refuses the claim. In 2026, with the Ministry of New and Renewable Energy (MNRE) enforcing strict HP caps under Component B and most state agencies tightening the pump-to-borewell match, getting the sizing right on day one decides whether you receive ₹2.5–₹4 lakh of subsidy or rework the application for six months.

This guide explains how borewell depth, static water level, and daily crop water requirement combine to dictate the right pump HP, the matching solar kWp, and the KUSUM subsidy slab you fall into. The numbers are pulled from MNRE’s KUSUM operating guidelines, Bureau of Indian Standards (BIS) IS 17385 for solar submersible pumps, and the Central Ground Water Board (CGWB) groundwater depth data we use across our installations.

Direct answer. For a borewell up to 30 feet, use a 1–2 HP surface pump with a 1.5–3 kWp solar array; 30–100 feet needs 3–5 HP submersible with 4.5–7.5 kWp; 100–200 feet needs 5–7.5 HP submersible with 7.5–11 kWp; 200–300 feet needs 7.5–10 HP submersible with 11–15 kWp. KUSUM Component B subsidises pumps up to 7.5 HP in most states, with a few permitting 10 HP. Match the pump to the dynamic head (depth × 1.2) and the crop’s daily litre requirement — not to your old diesel pump’s HP rating.

The rest of this article walks through the four variables that decide sizing, the depth-to-HP matrix we use on the field, water output benchmarks for each HP class, and the crop-by-crop sizing logic for cotton, wheat, vegetables, and sugarcane. If you’re still at the eligibility stage, read the PM KUSUM complete guide first; for the application workflow, see the KUSUM Component B application guide.

Why Borewell Depth Drives Pump Sizing

A solar pump’s job is to lift water from the static water level inside the borewell up to the discharge point — usually a storage tank or field outlet — while overcoming pipe friction along the way. The total energy required is set by the total dynamic head (TDH), measured in feet or metres, and TDH is dominated by borewell depth. Every additional 10 feet of depth adds roughly 0.43 kg/cm² of pressure the pump must beat. A 5 HP pump that delivers 10,000 litres per hour (LPH) at 50 feet of head delivers only 4,500 LPH at 150 feet — the same pump, less than half the water.

Solar pumps complicate this further because their output is variable. Unlike a grid pump that runs at full rated HP from 6 a.m. to 8 p.m., a solar pump produces full flow only between 10 a.m. and 3 p.m., tapering at the edges. CGWB’s regional water level reports show that across Rajasthan, Maharashtra, and Karnataka — three of the largest KUSUM Component B states — pre-monsoon static water levels have dropped 8–15 metres over the last decade. That drawdown directly raises the pump HP required for the same yield.

The takeaway: depth is not the only variable, but it is the dominant one. Get depth right, and the other three variables — flow, head, daily water need — fall into place around it.

The 4-Variable Borewell-to-Pump Sizing Method

We use a four-step framework on every site visit before quoting a pump. We call it The 4-Variable Borewell-to-Pump Sizing Method — measure depth, measure flow, calculate head, then size for daily water need. Each variable feeds the next; skip one and the pump arrives wrong.

Variable 1: Borewell Depth (Static and Dynamic)

Depth has two definitions and both matter. Total borewell depth is the drilled length from ground to the bottom of the casing. Static water level (SWL) is where the water stands when the pump is idle — typically 20–40 feet below the surface in north India, deeper in the south. Dynamic water level (DWL) is the level after the pump has been running 20–30 minutes; the column drops as water is extracted, and the drop is called drawdown.

Sizing must use DWL plus a safety margin, not SWL. A borewell drilled to 250 feet with an SWL of 80 feet and 40 feet of drawdown gives a DWL of 120 feet — that is the depth your pump suction sits below water. Ask your driller for the test pumping report; if you don’t have one, measure SWL with a weighted string and assume 30–40% drawdown for sizing.

Variable 2: Borewell Yield (Litres Per Minute)

Yield is the borewell’s natural refill rate — how many litres per minute (LPM) the aquifer can supply without running the well dry. A pump rated above the borewell yield will pull air, cavitate, and burn out within months. Yield is measured during the post-drilling test (the driller runs an air-compressor test for 4 hours and notes the steady flow).

Typical north Indian borewells yield 30–150 LPM. A 5 HP solar pump targeted at 8,000 LPH (133 LPM) needs a borewell that yields at least 133 LPM steady. If yield is 80 LPM, drop to a 3 HP pump or accept that the pump cycles on and off as the column refills. We always cap pump LPH at 80% of measured yield.

Variable 3: Total Dynamic Head (TDH)

TDH is what the pump actually works against, in feet or metres. Add three components:

• Suction lift / vertical lift = DWL (the depth from ground to dynamic water level).
• Delivery head = vertical distance from ground to your highest discharge point (tank inlet, sprinkler manifold).
• Friction head = pressure losses inside the delivery pipe; rule of thumb is 10–15% of vertical lift for a correctly sized pipe.

Rule of thumb for quick field sizing: TDH ≈ borewell depth × 1.2. A 150-foot borewell with a 20-foot overhead tank and properly sized 2-inch PVC delivers a TDH of around 180 feet. Solar submersible pump curves are published against TDH; pick the curve that delivers your required flow at your calculated TDH.

Variable 4: Daily Water Requirement by Crop

Pump HP must deliver enough water within the solar window (roughly 6 hours of usable daylight pumping for a fixed array, 8 hours for a tracker). Calculate daily need first, then back-solve HP.

A 2-acre cotton plot at peak season needs ~1,200 litres/day. With a 6-hour pumping window, that’s 200 LPH — comfortably handled by even a 2 HP pump at moderate depth. A 5-acre sugarcane plot consuming 30,000 L/day needs 5,000 LPH — a 5 HP pump at 100-foot head, or a 7.5 HP pump at 200-foot head. The crop dictates the LPH target; depth and head dictate the HP that delivers it.

Depth-to-HP Matrix — Definitive Table for KUSUM

This is the field matrix we use across every KUSUM Component B installation. It assumes typical Indian conditions: 5.5 peak sun hours, moderate friction losses, BIS IS 17385-certified submersible pumps.

Borewell depth	Recommended pump	Pump type	Solar kWp (rough)	Typical LPH (peak)	KUSUM Component B fit
0–30 ft	1–2 HP	Surface / monoblock	1.5–3 kWp	6,000–9,000	Eligible (low end)
30–60 ft	2–3 HP	Submersible	3–4.5 kWp	6,000–10,000	Eligible
60–100 ft	3–5 HP	Submersible	4.5–7.5 kWp	6,000–10,000	Eligible (most common)
100–150 ft	5 HP	Submersible	7.5 kWp	7,000–9,000	Eligible
150–200 ft	5–7.5 HP	Submersible	7.5–11 kWp	6,000–8,500	Eligible up to 7.5 HP cap
200–300 ft	7.5–10 HP	Submersible	11–15 kWp	6,500–9,000	7.5 HP universally; 10 HP in select states
300+ ft	10 HP+	Specialised submersible	15 kWp+	6,000–8,000	Usually exceeds Component B cap

Solar kWp uses the rule of thumb kWp ≈ HP × 1.5. Add 10% headroom if you’re east of 80° E longitude (Bihar, Odisha, West Bengal) where peak sun hours run 4.8–5.2 instead of 5.5. For details on the grid-tied variant that bypasses the HP cap and feeds export, see the KUSUM Component C grid-tied pump guide.

KUSUM Component	Pump capacity	Subsidy structure	Best for
Component B (standalone)	1–7.5 HP (10 HP in select states)	30% MNRE + 30% state + 40% farmer	Farmers without grid access
Component C — Individual Pump Solarisation	Up to 7.5 HP existing grid pump	30% MNRE + 30% state + 40% farmer	Grid pump replacement, export surplus
Component C — Feeder Solarisation	Aggregated MW scale	DISCOM-led	Cluster of farmers on one feeder

The Component B subsidy values mean a 5 HP standalone solar pump system costing ₹3.2 lakh draws ₹96,000 central + ₹96,000 state, leaving the farmer with ₹1.28 lakh. Confirm your state’s exact share — Rajasthan, Maharashtra, and Haryana stack differently — through the Rajasthan DREBP PM-KUSUM page.

Submersible vs Surface Pumps — Which Suits Which Depth

Surface pumps (also called monoblock or centrifugal) sit above ground and suck water up. Submersible pumps sit inside the borewell, below the water line, and push water up. Suction physics limits surface pumps to roughly 25 feet of vertical lift (a perfect vacuum can only lift water 33 feet at sea level; real pumps lose efficiency well before that). Beyond 30 feet DWL, surface pumps cavitate.

In our installations across Rajasthan and Maharashtra, more than 85% of KUSUM Component B sites use submersibles because the dynamic water level sits below the 25-foot suction limit. Surface pumps remain useful for canal-fed plots, large open wells, and tank-to-field boosters.

Get a free borewell sizing review. Send us your borewell test report and crop plan — we’ll match the right HP, kWp, and KUSUM slab in 24 hours. Talk to our solar pump team →

Daily Water Output: Litres per Hour by HP and Head

Pump curves are non-linear: doubling head does not halve flow, and doubling HP does not double flow at the same head. Use this table as a field reference for BIS IS 17385-certified solar submersibles operating at peak solar irradiance (around noon, clear sky, 1,000 W/m² plane-of-array).

Pump HP	30 ft head	60 ft head	100 ft head	150 ft head	200 ft head	300 ft head
1 HP	4,500 LPH	3,200 LPH	2,000 LPH	—	—	—
2 HP	8,500 LPH	6,500 LPH	4,500 LPH	2,800 LPH	—	—
3 HP	12,000 LPH	9,500 LPH	7,000 LPH	5,000 LPH	3,000 LPH	—
5 HP	18,000 LPH	14,000 LPH	10,000 LPH	8,000 LPH	6,000 LPH	3,500 LPH
7.5 HP	22,000 LPH	18,000 LPH	13,500 LPH	11,000 LPH	8,500 LPH	5,500 LPH
10 HP	28,000 LPH	23,000 LPH	18,000 LPH	14,500 LPH	12,000 LPH	8,000 LPH

Daily output uses 5–6 productive solar hours, not the full daylight stretch. A 5 HP pump at 100-foot head producing 10,000 LPH at peak yields roughly 50,000 litres on a clear day, 30,000–35,000 litres on a hazy or partly cloudy day. Always design for the lower number — the buffer prevents irrigation gaps in cloudy weeks.

For an honest cost comparison against the diesel pump you may already own, walk through the numbers in diesel vs solar pump ROI. The solar pump pays back in 4–5 years; the diesel pump never stops costing you fuel.

Common Undersizing and Oversizing Mistakes

Eight out of ten KUSUM sizing errors come from the same handful of patterns. We tag each one with the rework cost we’ve seen across the field.

1. 1
   Matching the diesel pump's HP rating. Solar pumps deliver variable output; a 5 HP diesel running 12 hours equals a 7.5 HP solar pump running 6 hours. Up-size when shifting from diesel.
2. 2
   Using static water level instead of dynamic. SWL is the at-rest depth; DWL is what the pump fights against. Skipping drawdown leads to a pump that runs dry in 20 minutes.
3. 3
   Ignoring delivery head and friction losses. A 50-foot delivery line and a 25-foot overhead tank can add 40% to the TDH the pump must beat.
4. 4
   Buying for peak summer yield only. Cloudy monsoon weeks drop output by 30–40%. Size with a winter and monsoon buffer if your crop cycle covers those months.
5. 5
   Picking 10 HP without checking state cap. Most state implementing agencies subsidise only up to 7.5 HP under Component B. The 8th–10th HP comes out of your pocket.
6. 6
   Over-sizing the solar array vs the pump. A 12 kWp array on a 5 HP pump wastes 30% of the panels; the variable frequency drive (VFD) caps motor draw at rated HP. Use the kWp ≈ HP × 1.5 rule.
7. 7
   Forgetting borewell yield cap. A 7.5 HP pump on a 60 LPM borewell short-cycles, burns the motor, and voids warranty. Pump LPH must stay below 80% of measured yield.
8. 8
   Skipping the BIS IS 17385 mark. KUSUM inspection rejects non-certified pumps. Always verify the pump model is on the latest BIS register before ordering.

Symptom	Likely cause	Fix
Pump runs but no water	Pump above dynamic water level	Lower the pump, or recalculate DWL
Pump short-cycles every 10 min	Borewell yield below pump LPH	Down-size pump or rotate pumping
Pump runs only midday	Solar array undersized for HP	Add 1–2 kWp panels or reposition for less shading
Pump trips frequently	VFD capacity below HP draw or wiring fault	Upgrade VFD; check cable gauge
Output drops 40% in monsoon	Cloudy weather + dirty panels	Clean panels weekly; accept seasonal variance
Motor burns within months	Cavitation (running dry)	Install dry-run sensor; verify DWL margin

If the pump installed under your KUSUM claim has failed, you may be eligible for a replacement under the warranty mechanism — see the KUSUM pump replacement claim guide.

Crop-Specific Sizing — Vegetables vs Wheat vs Cotton vs Sugarcane

Crop water demand is the final filter before locking the HP. The numbers below assume drip irrigation efficiency (90%); flood irrigation roughly doubles the requirement.

Crop	Litres/acre/day at peak	1-acre HP need (100 ft head)	5-acre HP need (100 ft head)
Vegetables (tomato, chilli, brinjal)	800–1,200 L	1–2 HP	3–5 HP
Wheat	400 L	1 HP	2 HP
Cotton	600 L	1–2 HP	3 HP
Sugarcane	1,500–2,000 L	2 HP	7.5 HP
Paddy (irrigated dry)	1,800 L	2 HP	7.5–10 HP
Banana / orchard	1,000 L	1–2 HP	5 HP

A 5-acre cotton farmer at a 120-foot borewell needs ~3,000 L/day. A 3 HP solar pump at that head delivers ~7,000 LPH peak — roughly 35,000–40,000 L/day. The pump exceeds need by 10x because cotton’s daily demand is low — the rest of the capacity goes to filling a buffer tank for early-morning or cloudy-day irrigation. For cotton specifically, see our dedicated solar pump for cotton farming sizing notes.

Verdict. Size your KUSUM solar pump to the maximum-demand crop in your rotation, not the average. A farmer running wheat in rabi and cotton in kharif sizes for cotton; one running sugarcane sizes for sugarcane. The pump’s variable output handles low-demand seasons fine, but it cannot exceed its rated curve in high-demand months.

For most KUSUM Component B applicants across north and central India working borewells in the 60–150 foot range with 2–5 acres under irrigation, a 5 HP submersible with 7.5 kWp solar array is the sweet spot — within the 7.5 HP cap, deep enough into the subsidy stack to make the payback work, and large enough to handle a full crop rotation.

How Heaven Green Energy Designs Solar Pumps by Borewell Profile

Heaven Green Energy is empanelled for KUSUM Component B across Rajasthan, Madhya Pradesh, Maharashtra, and Haryana. We’ve installed solar pumps from 1 HP to 10 HP across borewells ranging from 25 feet to 320 feet, and our sizing playbook is built from the failures we’ve fixed on competitors’ rework jobs. Our process:

• Borewell test report review — we ask for your driller’s air-compressor test, or send a field engineer to measure SWL, drawdown, and yield ourselves.
• CGWB depth verification — we cross-check your block’s water level data against your reported borewell depth to flag risk of further drawdown.
• TDH calculation — depth + delivery + friction, with safety margin built in. No back-of-envelope sizing.
• BIS-certified pump selection — only IS 17385-tested models, with curves matched to your TDH.
• State-cap-aware quoting — we won’t pitch a 10 HP system to a state with a 7.5 HP cap; the rejected subsidy isn’t a problem we’ll create for you.
• 5-year O&M coverage — annual panel cleaning, VFD inspection, and pump health checks under the standard KUSUM warranty plus our service stack.

Explore the services that match your project:

• PM KUSUM Complete Guide — eligibility, subsidy stacks, and how the three components compare.
• KUSUM Component B Application Guide — step-by-step portal walkthrough.
• Rajasthan DREBP PM-KUSUM — state-specific subsidy stacking for Rajasthan farmers.
• Solar Calculator — quick pump HP and subsidy estimate in 60 seconds.

If you’ve already paid the diesel-pump tax for years, the simplest way to start is to send us your last bill and borewell depth — we’ll tell you whether KUSUM saves you money in the first 12 months.

Frequently Asked Questions

What pump HP do I need for a 100-foot borewell under KUSUM?

For a 100-foot borewell with a dynamic water level around 60–80 feet, a 3–5 HP submersible pump is correct in most cases. At 5 HP, peak output is approximately 10,000 litres per hour against 100-foot head — enough for 3–5 acres of vegetables, cotton, or wheat under drip irrigation. The matching solar array is around 7.5 kWp. Both fall well within the KUSUM Component B 7.5 HP subsidy cap that applies in nearly every state.

How is solar pump HP linked to solar panel kWp?

The rule of thumb is kWp ≈ HP × 1.5 — so a 5 HP pump uses a 7.5 kWp array, a 7.5 HP pump uses an 11 kWp array, and a 10 HP pump uses a 15 kWp array. The multiplier accounts for the panel’s DC-to-AC inverter losses, cable losses, dust derating, and the variable frequency drive’s input requirements. Add 10% more kWp if your site has shading after 3 p.m. or if you’re in a low-irradiance zone like eastern India.

Can KUSUM Component B fund a 10 HP solar pump?

Most state implementing agencies cap KUSUM Component B subsidy at 7.5 HP. A few — including parts of Haryana, Karnataka, and Andhra Pradesh in specific tender rounds — have permitted 10 HP under expanded slabs, but the subsidy share above 7.5 HP is funded only by the state, not by the central MNRE share. Always confirm your state’s current tender circular before placing an order for a 10 HP pump under Component B.

What is the difference between static and dynamic water level when sizing a pump?

Static water level (SWL) is the depth at which water stands inside the borewell when no pump is running — the natural rest position of the aquifer. Dynamic water level (DWL) is where the water drops to once the pump has been running for 20–30 minutes; the drop is called drawdown and is typically 30–40% of the column. Pump sizing must use DWL plus a safety margin. Sizing against SWL leads to a pump that runs dry as soon as the column draws down.

Will my borewell yield support the pump HP I want to install?

A pump’s litres-per-hour rating must stay below 80% of the borewell’s measured yield — otherwise the pump will short-cycle, cavitate, or pull air. Borewell yield is measured during the post-drilling air-compressor test (the driller runs the well for 4 hours and notes steady flow). A 60 LPM borewell — 3,600 litres per hour — can support at most a 2–3 HP pump. Pushing 5 HP onto a 60 LPM well burns the motor inside one season.

Does KUSUM accept any solar pump or only certified ones?

KUSUM accepts only pumps certified to Bureau of Indian Standards BIS IS 17385, which sets the test standards for solar-photovoltaic submersible pumps. The pump model must also be listed in the MNRE-approved component list at the time of the state tender. Non-certified pumps are rejected at the field inspection stage; the subsidy is forfeited and you cannot re-claim against a replacement under the same application.

How long does a KUSUM solar pump last and what maintenance does it need?

A BIS-certified solar pump lasts 8–12 years on the pump end and 25 years on the solar panel side. Annual maintenance is light — panel cleaning every 15 days in the dry season, VFD inspection once a year, and a borewell test (yield, DWL) every 2–3 years to confirm the pump is still matched to the well. The KUSUM warranty mechanism covers pump replacement during the first 5 years if certified defects are documented through the implementing agency.

How do I check my state’s PM-KUSUM Component B subsidy share and HP cap?

Each state’s implementing agency — the Rajasthan Renewable Energy Corporation, MEDA in Maharashtra, HAREDA in Haryana, etc. — publishes a tender circular each financial year with the subsidy share (typically 30% state, matching the 30% MNRE share) and the HP cap. The circular is on the state agency website and on the national PM KUSUM portal. For Rajasthan specifically, the DREBP PM-KUSUM portal page lists the active slab.

Can I retrofit my existing diesel pump’s borewell with a KUSUM solar pump?

Yes — most existing borewells used by diesel pumps are suitable for solar conversion, provided the casing is sound and the yield is documented. You will replace the diesel pump head with a solar-rated submersible (or surface unit, depending on depth), add the solar array, and install the variable frequency drive. The KUSUM subsidy applies to the full new system; the salvage value of the diesel pump is incidental. Use the diesel vs solar pump ROI calculator to model the payback.