Grundfos 77S SP 4-inch stainless steel submersible well pump
Grundfos SP 45S10-3 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S15-4 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S20-5 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S30-7 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S50-9 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S50-12 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S75-15 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S75-18 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S100-22 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S100-25 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S150-28 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S150-31 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S150-34 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S150-37 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos 77S SP 4-inch stainless steel submersible well pump
Grundfos SP 45S10-3 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S15-4 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S20-5 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S30-7 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S50-9 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S50-12 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S75-15 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S75-18 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S100-22 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S100-25 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S150-28 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S150-31 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S150-34 performance curve, head, power and efficiency vs flow, 60 Hz
Grundfos SP 45S150-37 performance curve, head, power and efficiency vs flow, 60 Hz

Grundfos 45S SP Submersible Well Pump

HP - Motor Dia: 1 HP - 4 in Motor
Voltage - Phase: 230V 1Ph 3-Wire
Model - Head: 45S10-3 - 72-73 ft at 45 GPM

Product variant with selected options does not exist!
$1,836.02
SKU: 98924276
Weight : 32.0 lb
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Description
Grundfos · Submersible Well Pump
45S SP
45 GPM class stainless steel submersible well pump for 4 in and larger wells: 40 complete builds from 1 to 15 HP on Grundfos 4 in and 6 in motors, with a 2 in NPT discharge.
45 GPM Rated Flow
1-15 HP
72-942 ft Nominal Head
2 in NPT Discharge
4 in Min. Well · 6 in on 6 in Motors
230V 1Ph · 230V and 460V 3Ph
AISI 304 Stainless Steel
4.0-5.5 in Dia x 27.8-111.7 in L
28.6-172.9 lb Weight
Overview

The Grundfos 45S is the 45 GPM class of the Grundfos SP 4 in submersible range: a multistage pump end in AISI 304 stainless steel, factory-assembled on a Grundfos 4 in or 6 in submersible motor and sold as one complete pump. The 14 models run from 1 to 15 HP, single-phase 3-wire and three-phase, for household and farm wells, irrigation and light commercial supply.

  • Stainless steel hydraulics. Standard S-series impellers and chambers are AISI 304 stainless steel, supported by stainless external components.
  • Sand-handling bearing design. Water-lubricated bearings and sand channels reduce abrasive wear in suitable well-water service.
  • Built-in check valve. Helps prevent backflow after shutdown and reduces the risk of water hammer.
  • Upthrust control. A stop ring limits axial movement of the shaft during startup.
  • Protected inlet and cable routing. The inlet strainer limits larger-particle entry, while the screw-mounted cable guard secures the motor lead along the pump.
What Ships and What It Needs to Run

Included: the 45S pump end and its Grundfos motor, factory-assembled as one complete pump.

Single-phase 3-wire builds: control box required, ordered separately. Use the Grundfos SA-SPM6 3-Wire Control Box matched to the motor horsepower; the box for each HP is in the Control Box by Horsepower table under Models & Performance. The 1 HP box is sold in packs of ten.

Three-phase builds: magnetic starter or drive required, ordered separately. Wire the motor through a starter or a drive (VFD) rated for its horsepower and voltage.

Drop cable and splice kit: sized to your setting depth and ordered separately.

Genuine Grundfos equipment, factory-new in original packaging — sold and supported by Watermain Supply, an independent industrial supplier.
Warranty

24 months from date of installation, but not more than 30 months from date of manufacture. In Grundfos's words, products are “warranted to the original user only to be free of defects in material and workmanship”; the full terms are in the installation and operating instructions on the Data Sheet tab.

Specifications
Specification Value
Rated flow 45 GPM nominal; actual flow depends on the selected model and system head
Horsepower 1 to 15 HP
Supply options 230V 1Ph; 230V 3Ph; 460V 3Ph
Motor diameter 4 in or 6 in, depending on the complete-pump part number
Motor families MS402, MS4000C, MS6000C; configuration depends on selected assembly
Discharge 2 in NPT
Well diameter Assemblies with 4-inch motors fit 4-inch and larger wells; 6-inch motor selections require a 6-inch minimum well.
Maximum sand content 150 ppm for SP 35S-77S
Minimum pump submergence 5 ft below pumping water level, subject to installation requirements and adequate motor cooling
Curve tolerance ISO 9906 Annex A
Included Pump end and motor, assembled as one complete pump

Source: Grundfos SP data booklet and SP 45S data sheet, 60 Hz.

Models & Performance — Will It Do What You Need?

Each table reads like the curve: the head the pump adds at shut-off, along its curve and at the rated flow of 45 GPM, out to the end of the published curve. Pick a model whose head at your flow covers the pumping level, the pressure you need at the surface (2.31 ft per psi) and pipe friction.

45S · rated 45 GPM · 1 to 7-1/2 HP · 7 models
Model HP 0 GPM (Shut-off) 11.7 GPM 29 GPM 45 GPM (Rated) 58.6 GPM (Max)
45S10-3 1 92 89 85 72-73 50
45S15-4 1-1/2 119 119 114 98-99 69
45S20-5 2 153 150 145 124 88
45S30-7 3 219 211 204 174-178 126
45S50-9 5 280 275 268 232-234 170
45S50-12 5 — 365 353 301-306 220
45S75-15 7-1/2 — 461 450 386-390 289
45S · rated 45 GPM · 7-1/2 to 15 HP · 7 models
Model HP 0 GPM (Shut-off) 11.7 GPM 29 GPM 45 GPM (Rated) 58.6 GPM (Max)
45S75-18 7-1/2 551 551 536 458-463 341
45S100-22 10 673 674 657 564-568 420
45S100-25 10 759 763 742 632-640 470
45S150-28 15 860 863 843 727-729 545
45S150-31 15 949 953 930 801-803 598
45S150-34 15 1039 1042 1016 869-876 649
45S150-37 15 1128 1130 1100 939-942 698

Total head in feet. The shut-off and flow columns are read from the Grundfos 60 Hz curves, digitized from the published vector curves in the Grundfos SP 45S data sheet (60 Hz), at the nearest published point and rounded down. The (Rated) column is the nominal head Grundfos prints for each model at its rated flow, verbatim; where two figures are shown, builds on different motors or voltages differ slightly. 1 ft of head = 0.433 PSI. Full curves are in the product images and on the Data Sheet tab.

Control Box by Horsepower (single-phase 3-wire builds)

Motor HP Volts Models Standard control box
1 HP 230V 45S10-3 98821633 (10-pack)
1-1/2 HP 230V 45S15-4 98315254
2 HP 230V 45S20-5 98315256
3 HP 230V 45S30-7 98315258
5 HP 230V 45S50-9, 45S50-12 98315260

Grundfos US price list, January 2026, p. 48. Every box, Standard and Deluxe, is on our Grundfos SA-SPM6 3-Wire Control Box listing. Three-phase builds need a magnetic starter or drive instead.

What It Delivers on a 30/50 Pressure Switch

Output at 30 and 50 PSI · 2 HP · 1 model · depths 20 to 30 ft

GPM at 30 PSI (switch cut-in), by depth to water

Model 20 ft 30 ft
45S20-5 58 55

GPM at 50 PSI (switch cut-out), by depth to water

Model 20 ft 30 ft
45S20-5 38.5 27
Output at 30 and 50 PSI · 3 HP · 1 model · depths 60 to 100 ft

GPM at 30 PSI (switch cut-in), by depth to water

Model 60 ft 70 ft 80 ft 90 ft 100 ft
45S30-7 58 55.5 53.5 51 48

GPM at 50 PSI (switch cut-out), by depth to water

Model 60 ft 70 ft 80 ft 90 ft 100 ft
45S30-7 45.5 41.5 36.5 28 —
Output at 30 and 50 PSI · 5 HP · 1 model · depths 110 to 160 ft

GPM at 30 PSI (switch cut-in), by depth to water

Model 110 ft 120 ft 130 ft 140 ft 150 ft 160 ft
45S50-9 57 55 53 51 49 46.5

GPM at 50 PSI (switch cut-out), by depth to water

Model 110 ft 120 ft 130 ft 140 ft 150 ft 160 ft
45S50-9 47 44.5 41 37 30.5 9
Output at 30 and 50 PSI · 5 HP · 1 model · depths 160 to 250 ft

GPM at 30 PSI (switch cut-in), by depth to water

Model 160 ft 170 ft 180 ft 200 ft 225 ft 250 ft
45S50-12 57.5 56 54.5 52 47.5 42

GPM at 50 PSI (switch cut-out), by depth to water

Model 160 ft 170 ft 180 ft 200 ft 225 ft 250 ft
45S50-12 50.5 49 47 43 35.5 5
Output at 30 and 50 PSI · 7-1/2 HP · 2 models · depths 225 to 425 ft

GPM at 30 PSI (switch cut-in), by depth to water

Model 225 ft 275 ft 300 ft 350 ft 375 ft 425 ft
45S75-15 58 52.5 49 40 32 —
45S75-18 — 58 56 51 48.5 41

GPM at 50 PSI (switch cut-out), by depth to water

Model 225 ft 275 ft 300 ft 350 ft 375 ft 425 ft
45S75-15 52.5 45.5 40.5 — — —
45S75-18 — 54 51.5 45.5 41.5 26
Output at 30 and 50 PSI · 10 to 15 HP · 6 models · depths 375 to 1000 ft

GPM at 30 PSI (switch cut-in), by depth to water

Model 375 ft 450 ft 550 ft 700 ft 850 ft 1000 ft
45S100-22 56.5 51 38.5 — — —
45S100-25 — 55.5 48 — — —
45S150-28 — — 54 42 — —
45S150-31 — — 57.5 48.5 31.5 —
45S150-34 — — — 52.5 42.5 —
45S150-37 — — — 55.5 47.5 34.5

GPM at 50 PSI (switch cut-out), by depth to water

Model 375 ft 450 ft 550 ft 700 ft 850 ft 1000 ft
45S100-22 53 46 24.5 — — —
45S100-25 57 52 43 — — —
45S150-28 — 57 51 35.5 — —
45S150-31 — — 55 45 — —
45S150-34 — — 57.5 50 37.5 —
45S150-37 — — — 53 44.5 24

Calculated, not printed: Grundfos publishes no output table for the SP 45S. Each cell is the flow where the published 60 Hz curve meets the depth to water plus 69 ft (30 PSI) or 116 ft (50 PSI), interpolated between published points and rounded down to 0.5 GPM. 45S10-3, 45S15-4 cannot hold 50 PSI from a 20 ft depth on the published curve and are left out. Riser and pipe friction are not included. A dash on the shallow side means the flow runs past the end of the published curve; on the deep side, the pump cannot reach that pressure (or gives under 1 GPM).

Before You Buy — The Limits That Decide the Fit
Check What to confirm
Well size Assemblies with 4-inch motors fit 4-inch and larger wells; 6-inch motor selections require a 6-inch minimum well.
Submergence At least 5 ft of water above the pump at the pumping level
Single phase 3-wire builds need the Grundfos control box for the motor HP, ordered separately
Three phase A magnetic starter or drive rated for the motor, ordered separately
Cooling and temperature Water up to 104°F with at least 0.25 ft/s flowing past a 4 in motor (0.50 ft/s on a 6 in MS6000); drinking water up to 86°F
Sand 150 ppm for SP 35S-77S
Materials of Construction
Part Material
Impellers and chambers AISI 304 stainless steel
Valve casing and suction interconnector Cast stainless steel, EN 1.4308 (standard S construction)
Strainer, straps and cable guard AISI 304 stainless steel
Pump shaft Stainless steel, EN 1.4057
Bearings LSR/FKM elastomer
Neck rings TPU/PPS-FKM
Motor Water-filled Grundfos submersible motor; materials and seal design depend on motor type

Source: Grundfos SP data booklet, standard S construction.

For engineering-led sizing and selection support or a factory submittal, email sales@watermainsupply.com or call 1-888.510.4036.
© Watermain Supply — A division of E4 Industrial LLC
Data Sheet
SP 45S Data Sheet, 60 Hz (Curves, Dimensions, Weights)MS402 and MS4000 4 in Motor Data Sheet, 60 HzMS6000C and MMS6 6 in Motor Data Sheet, 60 HzGrundfos SP Submersible Pumps BrochureGrundfos SP Installation and Operating InstructionsGrundfos 5S-25S Service InstructionsSmartFlo Startup Guide for SP
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