Grundfos · Submersible Pump End
385S SP 8 in Pump End
385 GPM class stainless steel SP pump end for 8 in and larger wells, motor not included: 24 builds for 7-1/2 to 100 HP Grundfos 6 in and 8 in motors.
385 GPM Rated Flow
7-1/2-100 HP
60-831 ft Nominal Head
4 in NPT Discharge
8 in Min. Well
6 and 8 in Motor Fit
Grundfos Motor Flange
Built-In Check Valve
AISI 304 Stainless Steel
7.0-7.9 in Dia x 24.3-85.3 in L
38-215 lb Ship Weight
Overview
The Grundfos 385S is the 385 GPM class of the Grundfos SP 8 in submersible range, sold here as the pump end alone: AISI 304 stainless steel chambers and impellers, a built-in check valve and a 4 in NPT discharge, ready to mount on a Grundfos 6 in or 8 in submersible motor. Use it to rebuild an SP 385S on a sound motor, or to build a pump around a motor you already have; the complete Grundfos 385S SP 8 in Submersible Well Pump is listed separately.
Builds to 40 HP run on a 6 in motor; 40 to 60 HP builds come for a 6 in or an 8 in motor under separate part numbers, and 75 HP and up take an 8 in motor. Choose horsepower and motor size first, then the model, shown with the head it adds at 385 GPM.
What Ships and What It Needs to Run
Included: the Grundfos 385S SP pump end with its built-in check valve.
Submersible motor required, ordered separately. A Grundfos 6 in or 8 in motor of the horsepower in the selector: Grundfos MS6000C and MMS6 6 in Submersible Motor or Grundfos MMS8000 and MMS10000 Submersible Motor; the motor part number for each build is in the Motor by Horsepower table under Models & Performance.
Magnetic starter or drive required, ordered separately. Every motor for this pump end is three-phase; wire it through a starter or a drive (VFD) rated for its horsepower.
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 |
385 GPM |
| Motor horsepower |
7-1/2 to 100 HP |
| Motor |
Grundfos 6 in (MS6000C, MMS6) or 8 in (MMS8000), Grundfos motor flange |
| Discharge |
4 in NPT |
| Minimum well |
8 in |
| Check valve |
Built in |
| Minimum submergence |
8 ft |
| Curve tolerance |
ISO 9906 Annex A |
| Included |
Pump end only; motor and its control ordered separately |
Source: Grundfos SP 385S data sheet, 60 Hz, and Grundfos US price list, January 2026.
Models & Performance — Will It Do What You Need?
Each table reads like the curve: the head the pump end on its matching motor adds at shut-off, along its curve and at the rated flow of 385 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.
385S · rated 385 GPM · 7-1/2 to 40 HP · 10 models
| Model |
HP |
0 GPM (Shut-off) |
106 GPM |
264 GPM |
385 GPM (Rated) |
528 GPM (Max) |
| 385S75-1 |
7-1/2 |
100 |
91 |
71 |
60-61 |
31 |
| 385S100-2BA |
10 |
— |
— |
— |
— |
— |
| 385S150-2 |
15 |
193 |
183 |
146 |
123 |
64 |
| 385S200-3A |
20 |
259 |
247 |
201 |
163-165 |
73 |
| 385S250-3 |
25 |
290 |
278 |
225 |
187-189 |
101 |
| 385S250-4B |
25 |
346 |
332 |
269 |
220-222 |
103 |
| 385S300-4 |
30 |
382 |
367 |
298 |
234-249 |
130 |
| 385S300-5BB |
30 |
404 |
389 |
316 |
254-257 |
108 |
| 385S400-5 |
40 |
480 |
463 |
377 |
314 |
168 |
| 385S400-6B |
40 |
535 |
517 |
421 |
347-351 |
169 |
385S · rated 385 GPM · 50 to 100 HP · 9 models
| Model |
HP |
0 GPM (Shut-off) |
106 GPM |
264 GPM |
385 GPM (Rated) |
528 GPM (Max) |
| 385S500-6 |
50 |
573 |
556 |
454 |
375 |
204 |
| 385S500-7A |
50 |
— |
— |
— |
414-420 |
— |
| 385S500-7 |
50 |
— |
— |
— |
— |
— |
| 385S600-8 |
60 |
766 |
746 |
613 |
494-511 |
279 |
| 385S750-9 |
75 |
866 |
845 |
696 |
582 |
320 |
| 385S750-10 |
75 |
960 |
935 |
770 |
643 |
352 |
| 385S1000-11 |
100 |
1054 |
1028 |
846 |
711 |
386 |
| 385S1000-12 |
100 |
1145 |
1117 |
919 |
771 |
416 |
| 385S1000-13 |
100 |
1244 |
1215 |
1001 |
831 |
457 |
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 385S 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. No published curve for 385S100-2BA, 385S500-7A, 385S500-7: rated figure only, full curve on request. 1 ft of head = 0.433 PSI. Full curves are in the product images and on the Data Sheet tab.
Motor by Horsepower
| Motor HP |
6 in Grundfos motor (230V / 460V) |
8 in Grundfos MMS8000 (460V) |
| 7-1/2 HP |
96166181 / 96166161 |
— |
| 10 HP |
96166182 / 96166162 |
— |
| 15 HP |
96166184 / 96166164 |
— |
| 20 HP |
96166186 / 96166166 |
— |
| 25 HP |
96166187 / 96166167 |
— |
| 30 HP |
96166188 / 96166168 |
— |
| 40 HP |
96166170 |
99973360 |
| 50 HP |
99600226 |
99973361 |
| 60 HP |
99673485 |
99973363 |
| 75 HP |
— |
99973364 |
| 100 HP |
— |
99973365 |
Grundfos US price list, January 2026, the 385S pages. 6 in motors are on our Grundfos MS6000C and MMS6 6 in Submersible Motor listing, 8 in motors on Grundfos MMS8000 and MMS10000 Submersible Motor.
Before You Buy — The Limits That Decide the Fit
| Check |
What to confirm |
| Motor |
A Grundfos 6 in or 8 in submersible motor of the horsepower in the selector, with a Grundfos motor flange; ordered separately |
| Motor control |
Magnetic starter or drive for the three-phase motor |
| Well size |
8 in casing or larger |
| Submergence |
At least 8 ft of water above the pump |
| Duty point |
Choose the model from the Grundfos curve at your flow and total head. Send us the pumping level, pipe run and pressure and we will check it against the curve |
Materials of Construction
| Part |
Material |
| Pump |
Stainless steel, EN 1.4301 (AISI 304) |
| Impellers |
Stainless steel, EN 1.4301 (AISI 304) |
Source: Grundfos SP data booklet.
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
