Choosing the wrong submersible well pump size is one of the costliest mistakes a homeowner, farmer, or project contractor can make. Undersize it, and you get dry-run burnout, short cycling, overheated motor, and premature seal failure. Oversize it, and you face water hammer, wasted energy, accelerated well cone collapse, and sand intrusion. In extreme cases, incorrect sizing accelerates well yield decline — effectively shortening the life of the well itself.
At Jingong (Zhejiang Jingong Technology Co., Ltd.), we’ve been manufacturing submersible well pumps, surface/land pumps, solar DC pumps, and gasoline/diesel engine pumps for 15+ years, supplying 40+ countries across residential, agricultural, and industrial projects. This guide consolidates the same internal sizing worksheet our engineering team uses for custom well solutions — adapted for DIY well owners, irrigation contractors, and procurement buyers alike.
We’ll walk through:
- Two non-negotiable sizing parameters: GPM flow rate and TDH (Total Dynamic Head)
- Pre-sizing field measurements you must take before buying anything
- A step-by-step formula with real residential and farm examples
- Scenario-based cheat sheets (home / farm / off-grid / shallow-deep / industrial)
- Oversize vs undersize risks, and how Jingong’s full pump lineup (submersible + surface + solar + gas/diesel) covers every well condition
📌 Primary keyword anchor for this page: what size submersible pump do I need for my well — if you’re searching that exact phrase, start with Section 2 below.
2. Submersible Well Pump Sizing Core Principles (The Technical Foundation)
Before looking at any product brochure, you need two numbers. Every professional NGWA (National Ground Water Association) sizing worksheet and Hydraulic Institute standard starts here.
2.1 Submersible Well Pump Flow Rate (GPM) — How much water do you actually need?
GPM = gallons per minute delivered at the furthest fixture under peak demand. The golden rule: your pump’s rated GPM should be ≤ your well’s sustainable yield, otherwise you’ll pull the well below drawdown and cause sand pumping, bearing wear, and eventually well collapse.
| Application | Typical Peak GPM | Jingong Note |
|---|---|---|
| 2–3 bedroom home (1–2 baths) | 6–8 GPM | Minimum for shower + washer overlap |
| 3–4 bedroom home (2–3 baths) | 8–12 GPM | US residential baseline per NGWA |
| 5+ bedroom / large home | 12–16 GPM | May need larger pressure tank |
| Drip irrigation (small farm) | 5–15 GPM | Continuous duty; check well yield first |
| Sprinkler irrigation / pasture | 15–50+ GPM | Often requires 6″+ well or multiple pumps |
| Livestock watering (cattle) | 10–30 GPM | Tank refill + trough circulation |
| Industrial / commercial supply | 50–500+ GPM | See high-flow submersible series |
Fixture counting shortcut (US residential): 1 GPM per water-using fixture (shower head, faucet, dishwasher, washing machine, outdoor spigot). If you have 3 bathroom groups + 2 kitchen + 1 washer + 2 outdoor spigots = 8 GPM minimum. Add 20% buffer → spec a 10 GPM pump.
🔗 : See our residential submersible well pump series (4″, 6″, stainless/QJ models, 0.37–7.5 kW).
2.2 Total Dynamic Head (TDH) — How hard the pump must work
TDH = Static Lift + Drawdown + Vertical Discharge Height + Friction Loss (pipe + fittings + valves) + Pressure Tank/Nozzle Requirement + Safety Margin.
The industry-standard TDH formula:
TDH (ft) = (Static Water Level below ground, ft) + (Drawdown during pumping, ft) + (Discharge height from ground to outlet, ft) + (Friction loss in pipe + fittings, ft) + (Required pressure at outlet, expressed as ft: PSI × 2.31) + (Safety margin 10–20%)
Example constants Jingong field teams use:
- Friction loss (4″ PVC, 10 GPM): ~0.4 ft per 100 ft of pipe
- Friction loss (1¼″ poly, 10 GPM): ~4.5 ft per 100 ft
- One 90° elbow ≈ 0.6–1.0 ft loss (depends on diameter)
- Check valve / foot valve: 1–3 ft each
- Pressure tank setpoint 40/60 PSI: use 60 PSI × 2.31 = 138.6 ft equivalent head
📚 External reference: well pump sizing guidelines and Hydraulic Institute pump standards both use this TDH methodology.
2.3 HP (Horsepower) Matching — Connecting TDH + GPM to motor size
Once you have TDH and GPM, HP falls out of the pump curve. General rules of thumb (4″ submersible, 230V, 60 Hz):
| Well Depth (approx) | TDH Range | Recommended HP | Typical GPM @ that HP |
|---|---|---|---|
| Shallow <100 ft | 50–150 ft | ½ – ¾ HP | 6–12 GPM |
| Medium 100–200 ft | 150–300 ft | 1 – 1½ HP | 10–25 GPM |
| Deep 200–400 ft | 300–600 ft | 2 – 3 HP | 15–40 GPM |
| Very deep >400 ft | 600–1,000+ ft | 5 – 10+ HP | 20–80+ GPM |
⚠️ Jingong engineering note: Don’t “over-HP” hoping for futureproofing. A 2 HP pump forced into a 100 ft TDH load will operate far right on its curve → lower efficiency, higher sand velocity through impellers, shorter life. Match the curve, not just the hole depth.
🔗 Browse by HP → ½ HP submersible well pumps | 1 HP | 2 HP | 5 HP+
3. Must-Measure Well Parameters Before Sizing (Field Checklist)
You cannot size accurately from “my well is 200 feet deep” alone. You need these four measurements. If you skip them, any online calculator is guessing.
3.1 Well Depth, Static Water Level (SWL), and Drawdown
- Well depth: total drilled depth (not the same as water column)
- Static water level: distance from ground surface to water when pump has been off ≥ 24 hrs
- Drawdown: how far the water level drops when pumping at a given GPM (measured after 1 hr continuous run)
📏 How to measure SWL without special gear: tape a weight + marker on nylon line, lower until splash, mark, retrieve, measure. For drawdown, repeat while pump runs (or hire a driller with an electric sounder).
3.2 Well Yield (GPM output of the well itself)
This is the single most ignored number. Pump GPM must be ≤ well yield, ideally 80% of yield to leave recharge buffer.
Quick yield test: time how long it takes to fill a 5-gallon bucket while pumping at expected rate. Extrapolate. Or — better — do a 4-hour constant-rate test with drawdown logged hourly. Low-yield wells (<5 GPM) require either a low-yield specialty submersible or a large pressure tank + cycle-stop strategy.
🔗 Low Yield Well Pump Solutions (Jingong guide)
3.3 Pipe Diameter, Length, and Fitting Count
Friction loss scales fast on undersized pipe:
- 1″ pipe at 15 GPM → ~8 ft loss / 100 ft
- 1¼″ pipe at 15 GPM → ~3 ft loss / 100 ft
- 1½″ pipe at 15 GPM → ~1.5 ft loss / 100 ft
Rule: match pipe ID so velocity stays < 5 ft/sec (preferably < 4 ft/sec) to avoid cavitation and excessive TDH.
3.4 Working Pressure Requirement (PSI)
Residential pressure tanks commonly set at 40/60 PSI (cut-in/cut-out). Sprinkler systems often need 50–80 PSI at heads. Each 10 PSI = ~23 ft of head. This goes INTO your TDH calc.
4. Step-by-Step Submersible Well Pump Sizing Formula & Real Examples
4.1 Submersible Well Pump The Standard Sizing Workflow (Jingong Field Method)
- Define required GPM (fixture count or irrigation zone calc)
- Measure / confirm well yield ≥ pump GPM × 1.2
- Calculate TDH using Section 2.2 formula
- Plot (GPM, TDH) on pump curve → select model where operating point sits between BEP (best efficiency point) and end-of-curve, but NOT far right
- Select HP, voltage (115V/230V single phase for residential; 230V/460V 3-phase for farm/industrial), and material (cast iron vs 304/316 SS vs duplex)
- Add 10–20% safety margin on TDH (not on GPM — oversizing GPM relative to well yield is dangerous)
4.2 Case A: Residential 150 ft Well (3-bedroom home, 2 baths)
Given:
- Well depth: 150 ft, SWL: 40 ft, drawdown @ 10 GPM: 25 ft
- Discharge: ground to pressure tank inlet = 5 ft; pressure tank 40/60 PSI → use 60 PSI = 139 ft
- Pipe: 1¼″ poly, 150 ft total (100 ft vertical + 50 ft horizontal to house)
- Fittings: 4 elbows, 1 check valve
TDH calc:
- Static lift + drawdown = 40 + 25 = 65 ft
- Discharge height = 5 ft
- Friction (1¼″ @ 10 GPM ≈ 2 ft/100 ft): 150 ft × 2/100 = 3 ft
- Fittings: 4×0.7 + 1×2 = 4.8 ft
- Pressure: 60 PSI × 2.31 = 139 ft
- Subtotal = 65 + 5 + 3 + 4.8 + 139 = 216.8 ft
- +15% safety = ~250 ft TDH
Selection: 10 GPM @ 250 ft TDH → Jingong 4″ submersible, 1 HP or 1½ HP, 230V single phase, stainless steel, 10 GPM rated curve passing through 250 ft. Pair with 20-gal pressure tank (or 30-gal for longer cycles).
4.3 Case B: Farm Irrigation, 300 ft Well, 35 GPM Sprinklers
Given: Well yield tested = 45 GPM (so 35 GPM pump is safe). SWL 80 ft, drawdown @ 35 GPM = 60 ft. Discharge to pivot inlet = 10 ft. Pipe = 2″ PVC, 350 ft. Pressure needed at pivot = 70 PSI.
TDH: 80+60+10 + friction(~6 ft) + fittings(~8 ft) + 70×2.31(162 ft) = ~326 ft + 15% = ~375 ft TDH.
Selection: 35 GPM @ 375 ft → 4″ or 6″ submersible, 3 HP, 3-phase 230V or 460V, VFD recommended for soft start. Jingong agricultural submersible series, or — if no 3-phase power at site — consider our diesel engine drive pump with belt-driven centrifugal as alternative.
5. Scenario-Based Pump Sizing Cheat Sheet (Full Jingong Product Mapping)
This is where we extend beyond “just submersible” — Jingong’s full lineup means you’re never stuck. Each scenario below links to the right product type.
5.1 Residential Home Submersible Well Pump (Single-family)
Typical: 100–300 ft depth, 6–12 GPM, 40/60 PSI, 230V single phase.
Sizing shorthand: TDH usually 200–350 ft. ½–1½ HP. 4″ stainless submersible is the default choice for <4″ casing; if casing is 2″–3″, consider 3″ slim submersible or (if depth <25 ft) a jet/surface land pump instead.
🔗 Jingong Residential Submersible Series →
5.2 Farm Irrigation & Pasture
Typical: 200–500 ft, 15–80 GPM, sprinkler/pivot pressure 50–80 PSI, often 3-phase or generator-powered.
Sizing: 1½–5 HP common. Large farms pushing 100+ GPM go to 6″–8″ submersibles or diesel engine drive centrifugal pumps (especially in remote fields with no grid).
🔗 Jingong Agricultural Submersible → | Diesel Irrigation Pump →
5.3 Off-Grid / Remote Area Well
Pain point: No utility power, or unreliable grid. Two Jingong paths:
- Solar DC submersible pump: MPPT controller, runs directly off PV array + battery buffer. Sizes ½–2 HP, GPM 3–40, TDH up to 650 ft depending on stage count. Perfect for livestock, cabin, village water.
- Gasoline/Diesel engine pump: Portable, no wiring, good for construction sites and temporary irrigation.
🔗 Jingong Solar Well Pump Sizing → | Gasoline Engine Pump →
5.4 Shallow Well (<25 ft) vs Deep Well (>100 ft)
- Shallow (<25 ft): Jet pump or surface land pump is cheaper, serviceable above ground. No need to pull pump for maintenance.
- Deep (>100 ft): Submersible mandatory. 4″ QJ series (GB/T 2816 compliant) covers 100–500 mm casing, flows 5–1200 m³/h, heads 6–1800 m.
5.5 Industrial & Commercial Water Supply
High-rise boosting, mining dewatering, municipal supply. Flows 50–500+ GPM, heads 300–1500 ft. Jingong high-head stainless multistage submersibles, 316L / duplex options for corrosive groundwater.
🔗 Jingong Industrial Submersible →
6. Oversize vs Undersize: Risks & Fixes
6.1 Undersized Pump Symptoms
- Short cycling: Pressure switch clicks on/off every 30–60 sec → pressure tank bladder fails fast
- Motor overheating: Running too far right on curve, low cooling flow through motor jacket
- Dry run / sand pumping: Pump GPM > well yield → water level drops below intake → seals burn, sand scours impellers
- Inadequate pressure at fixtures: Shower “dribbles” when washer runs
Fix: Re-audit GPM need + well yield. Often the cure is a lower-HP pump with correct GPM cap + larger pressure tank, not a bigger pump.
6.2 Oversized Pump Symptoms
- Water hammer: When pump kicks on/off, pressure spikes damage pipes/fixtures
- Well cone collapse / sand influx: Excessive drawdown from too-high GPM vs yield
- Energy waste: Operating left of BEP = lower efficiency, higher $/gallon
- Pump cycling too fast even with big tank: Because GPM is so high it empties tank in 20 sec
Fix: Downsize HP, add VFD (variable frequency drive) to trim speed, or install cycle-stop valve / larger pressure tank.
7. Submersible Well Pump vs Jingong’s Other Main Pump Types
A well doesn’t always mean “buy a submersible.” Here’s how Jingong’s full catalog maps to well conditions:
7.1 Submersible vs Surface (Land) Pump
| Submersible Well Pump | Surface/Jet/Land Pump | |
|---|---|---|
| Max suction/lift | No limit (pushes from bottom) | ~25 ft practical limit |
| Noise | Quiet (underwater) | Audible at pump location |
| Service | Pull from well to repair | Above-ground, easy access |
| Best for | >25 ft depth, 4″+ casing | <25 ft, shallow well, lake/pond draw |
🔗 Jingong Surface/Land Pump Series →
7.2 Solar Well Pump vs Electric Submersible
- Electric submersible: Grid-tied, 230V/460V, runs 24/7, higher sustained GPM
- Solar DC submersible: Off-grid, daylight-run (or battery night), lower OPEX, no fuel, ideal for remote Africa/Middle East/Latin America projects
Jingong solar well pumps use brushless DC motors, helical rotor or centrifugal multistage, MPPT controllers compatible with 300–600W panel arrays up to 3 kW systems.
🔗 Solar Well Pump Sizing & Models →
7.3 Gas/Diesel Engine Pump vs Submersible
When the well is <30 ft but you’re irrigating a remote field with no power — or when grid is down and you need emergency supply — Jingong gasoline (2–13 HP) and diesel (4–30+ HP) engine-driven centrifugal pumps are the fallback. Not for deep wells (suction limit!), but perfect for:
- Construction dewatering pits
- Emergency backup to submersible
- Portable irrigation from pond + shallow well combo
🔗 Gasoline Engine Pump → | Diesel Engine Pump →
8. Professional FAQ (Targeting Google FAQ Rich Snippet)
Q1: What size submersible pump do I need for a 100 ft well?
A: For a typical 3–4 bedroom home on a 100 ft well (SWL ~30 ft, drawdown ~15 ft, 40/60 PSI tank), expect TDH ~180–220 ft. A ½–1 HP, 8–12 GPM 4″ submersible is the common match. Confirm your well yield first — if the well only produces 5 GPM, downsize pump to 5–6 GPM even if fixtures suggest 10 GPM.
Q2: What size submersible pump for a 200 ft well?
A: 200 ft well with SWL 60 ft + drawdown 30 ft + 60 PSI = TDH typically 280–340 ft. 1–1½ HP, 10–18 GPM range fits most residential. Farm/irrigation on same depth pushes to 2–3 HP, 25–40 GPM.
Q3: How many GPM do I need for a residential well pump?
A: Fixture-count method: 1 GPM per fixture, then add 20%. Most 3-br/2-ba homes land at 8–12 GPM. Your pump GPM must still be ≤ 80% of well yield — the well, not the house, sets the ceiling.
Q4: Can I use a solar pump for a deep well?
A: Yes, up to a point. Jingong solar DC submersibles handle up to ~650 ft TDH in high-stage configurations (helical rotor for high head/low GPM; centrifugal multistage for moderate head/higher GPM). Beyond that, grid-tied electric submersible + backup diesel/gas is the more common combo.
Q5: Is a submersible pump better than a surface pump for wells?
A: For any well deeper than 25 ft, yes — submersible pushes water up, surface pump can only pull ~25 ft max (and that’s optimistic; real-world ~18 ft). For <25 ft shallow wells, a surface jet pump or land pump is cheaper and easier to service.
Q6: What HP well pump do I need for irrigation?
A: Depends on zone GPM + TDH. Small garden drip (10 GPM, 150 ft TDH) → ½–1 HP. Sprinkler pivot (35 GPM, 350 ft TDH) → 3 HP. Large center pivot (80+ GPM, 400+ ft) → 5–10 HP, often 3-phase or diesel drive. Always confirm well yield before locking HP.
9. Conclusion & Custom Solution (Jingong’s Value Proposition)
Sizing a submersible well pump isn’t a “pick by horsepower” guess — it’s a field-measured workflow: GPM need → well yield check → TDH calc → pump curve match → HP + voltage + material selection. Get any one of those wrong and the symptom shows up 6 months later as a burnt motor or a sand-clogged well.
Jingong’s advantage as a manufacturer (not just trader) is that we don’t force you into one pump type. Our Zhejiang plant produces:
- Submersible well pumps (4″/6″/8″ QJ series, stainless 304/316, 0.37–110 kW, heads to 600 m+, GB/T 2816 compliant)
- Surface/land pumps (jet, centrifugal, shallow well)
- Solar DC well pumps (BLDC, helical + multistage, off-grid kits)
- Gasoline & diesel engine pumps (portable, irrigation, emergency)
Need a custom sizing worksheet for your well? Send us:
- Well depth, SWL, drawdown (or just “depth + yield GPM” if you don’t have drawdown)
- Intended use (home / irrigation / livestock / industrial)
- Power available (single phase 230V? 3-phase? solar? none?)
- Casing diameter (2″? 4″? 6″?)
We’ll return a 1-page sizing sheet + 2–3 model recommendations from our catalog, with EXW/FOB pricing for your project scale.
📩 Contact Jingong Engineering: [your contact form / email] | 🌐 Back to Jingong Pump Index