Grundfos · Submersible Well Pump
385S SP
385 GPM class stainless steel submersible well pump for 8 in and larger wells: 18 complete builds from 7-1/2 HP to 40 HP on 6 in Grundfos motors, with a 4 in NPT discharge.
385 GPM Rated Flow
7-1/2-40 HP
60-347 ft Nominal Head
1 to 6 Stages
4 in NPT Discharge
8 in Min. Well
230V and 460V 3Ph
AISI 304 Stainless Steel
cCSAus
7.0 in Dia x 46.6-89.8 in L
135.9-282.2 lb Weight
What Ships and What It Needs to Run
Included: the 385S pump end and its Grundfos motor, factory-assembled as one complete pump.
Three-phase 230V and 460V builds: motor starter or drive required, ordered separately. Wire the motor through a magnetic starter or a drive (VFD) rated for its horsepower and voltage.
Drop cable and splice kit: sized to your setting depth and ordered separately.
Overview
The Grundfos 385S is the 385 GPM class of the Grundfos SP submersible range, built for 8 in and larger wells. Pump and impellers are AISI 304 stainless steel. Each build here is a complete pump: the 385S pump end and a Grundfos submersible motor, supplied together under one part number, with a 4 in NPT discharge.
Typical uses listed by Grundfos include groundwater supply, irrigation, residential water pressure boosting and municipal wells.
The 385S range here runs on 6 in Grundfos MS6000C motors (7-1/2-40 HP). The motor for each build is listed in the Models & Ratings table.
All builds are three-phase, at 230V or 460V.
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.
Single Pump or a Set?
Each 385S serves one well as a single unit. For a duty/standby pair across two wells, or a flow outside what one 385S carries, send us the duty: the 475S covers higher flows in the same 8 in well range, and the 300S and smaller SP 6 in models cover lower flows, and we will size the set with you.
Check the Part Number
The model code reads flow class, horsepower and stages: 385S150-2 is the 385S with a 15 HP motor and 2 stages. The same model can come in more than one build, so order by part number. In the selector, choose horsepower and voltage first, then the model and stage count. The part number for every build is in the Models & Ratings table.
-
385S100-2AB, 385S200-3A, 385S250-4B, 385S300-5BB and 385S400-6B: letters after the stage count mean reduced-diameter impellers, which trim the head to fit a duty. The selector shows the full model, letters included.
Models & Ratings
| Model |
Part No. |
HP |
Voltage |
Motor |
Motor Part No. |
Pump End Part No. |
Control Box |
| 385S75-1 |
16B73001 |
7-1/2 |
230V 3Ph |
MS6000C 6 in |
96166181 |
16B70001 |
— |
| 385S75-1 |
16B73601 |
7-1/2 |
460V 3Ph |
MS6000C 6 in |
96166161 |
16B70001 |
— |
| 385S100-2AB |
16B730E2 |
10 |
230V 3Ph |
MS6000C 6 in |
96166182 |
16B700E2 |
— |
| 385S100-2AB |
16B736E2 |
10 |
460V 3Ph |
MS6000C 6 in |
96166162 |
16B700E2 |
— |
| 385S150-2 |
16B73002 |
15 |
230V 3Ph |
MS6000C 6 in |
96166184 |
16B70002 |
— |
| 385S150-2 |
16B73602 |
15 |
460V 3Ph |
MS6000C 6 in |
96166164 |
16B70002 |
— |
| 385S200-3A |
16B730A3 |
20 |
230V 3Ph |
MS6000C 6 in |
96166186 |
16B700A3 |
— |
| 385S200-3A |
16B736A3 |
20 |
460V 3Ph |
MS6000C 6 in |
96166166 |
16B700A3 |
— |
| 385S250-3 |
16B73003 |
25 |
230V 3Ph |
MS6000C 6 in |
96166187 |
16B70003 |
— |
| 385S250-4B |
16B730C4 |
25 |
230V 3Ph |
MS6000C 6 in |
96166187 |
16B700C4 |
— |
| 385S250-3 |
16B73603 |
25 |
460V 3Ph |
MS6000C 6 in |
96166167 |
16B70003 |
— |
| 385S250-4B |
16B736C4 |
25 |
460V 3Ph |
MS6000C 6 in |
96166167 |
16B700C4 |
— |
| 385S300-4 |
16B73004 |
30 |
230V 3Ph |
MS6000C 6 in |
96166188 |
16B70004 |
— |
| 385S300-5BB |
16B730D5 |
30 |
230V 3Ph |
MS6000C 6 in |
96166188 |
16B700D5 |
— |
| 385S300-4 |
16B73604 |
30 |
460V 3Ph |
MS6000C 6 in |
96166168 |
16B70004 |
— |
| 385S300-5BB |
16B736D5 |
30 |
460V 3Ph |
MS6000C 6 in |
96166168 |
16B700D5 |
— |
| 385S400-5 |
16B73605 |
40 |
460V 3Ph |
MS6000C 6 in |
96166170 |
16B70005 |
— |
| 385S400-6B |
16B736C6 |
40 |
460V 3Ph |
MS6000C 6 in |
96166170 |
16B700C6 |
— |
Part numbers, motors, pump ends and control boxes: Grundfos US price list, effective January 1, 2026.
Shared Specifications
| Specification |
Value |
| Rated flow |
385 GPM |
| Horsepower |
7-1/2 to 40 HP |
| Stages |
1 to 6 |
| Discharge |
4 in NPT female |
| Minimum well size |
8 in |
| Voltage and phase |
230V 3Ph (7-1/2-30 HP); 460V 3Ph (7-1/2-40 HP) |
| Motors |
6 in Grundfos MS6000C (7-1/2-40 HP) |
| Liquid temperature |
MS6000C 6 in: up to 104°F (40°C) |
| Approvals |
cCSAus and CULDWUS on every build (Grundfos Product Center codes) |
| Curve tolerance |
ISO 9906 |
| Minimum submergence |
8 ft |
| Included |
Pump end and motor, assembled as one complete pump |
Performance — Will It Do What You Need?
Every 385S is rated at 385 GPM. The figure below is the nominal head Grundfos publishes for each model at that rated flow: the total head the pump adds, in feet. Pick a model whose nominal head covers your pumping level plus the pressure you need at the surface (2.31 ft per psi) plus pipe friction.
| Model |
Stages |
HP |
Nominal Head at 385 GPM, ft |
| 385S75-1 |
1 |
7-1/2 |
60-61 |
| 385S100-2AB |
2 |
10 |
87 |
| 385S150-2 |
2 |
15 |
123 |
| 385S200-3A |
3 |
20 |
163-165 |
| 385S250-3 |
3 |
25 |
187-189 |
| 385S250-4B |
4 |
25 |
220-222 |
| 385S300-4 |
4 |
30 |
234-249 |
| 385S300-5BB |
5 |
30 |
254-257 |
| 385S400-5 |
5 |
40 |
314 |
| 385S400-6B |
6 |
40 |
347 |
Source: Grundfos SP data booklet, 60 Hz, May 2026 (SP 385S tables). Where two figures are shown, the builds on different motors or voltages differ slightly. Performance conforms to ISO 9906. For flows other than the rated flow, the 385S head and power curves for the builds listed here are in the product images, and the 385S data sheet on the Data Sheet tab carries the full curves and tables.
Dimensions & Weights
| Model |
Motor |
Overall Length, in |
Max. Diameter, in |
Net Weight, lb |
| 385S75-1 |
6 in |
46.6 |
7.0 |
135.9 |
| 385S100-2AB |
6 in |
52.6 |
7.0 |
169.2 |
| 385S150-2 |
6 in |
57.2 |
7.0 |
169.2 |
| 385S200-3A |
6 in |
65.2 |
7.0 |
188.1 |
| 385S250-3 |
6 in |
67.4 |
7.0 |
209.7 |
| 385S250-4B |
6 in |
72.4 |
7.0 |
239.4 |
| 385S300-4 |
6 in |
75.0 |
7.0 |
239.4 |
| 385S300-5BB |
6 in |
80.0 |
7.0 |
247.5 |
| 385S400-5 |
6 in |
84.8 |
7.0 |
247.5 |
| 385S400-6B |
6 in |
89.8 |
7.0 |
282.2 |
Source: Grundfos SP data booklet, 60 Hz, May 2026. Max. diameter includes the cable guard and motor. Net weight for part 16B73003 is from Grundfos Product Center; the booklet prints 188.1 lb. Net weight for part 16B73603 is from Grundfos Product Center; the booklet prints 188.1 lb. Net weight for part 16B736C6 is from Grundfos Product Center; the booklet prints 252.0 lb.
Before You Buy — The Limits That Decide the Fit
| Check |
What to confirm |
| Well size |
8 in casing or larger |
| Submergence |
At least 8 ft of water above the pump |
| Three phase |
A magnetic starter or drive is needed and is not included |
| Power |
Match horsepower, voltage and phase to your service |
| Water temperature |
MS6000C 6 in: up to 104°F (40°C) |
| 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) |
| Motor, 6 in MS6000C |
Stainless steel, DIN W.-Nr. 1.4301 (AISI 304) |
Source: Grundfos Product Center.
