Compact Submersible Centrifugal Pumps: How to Choose by Head and Flow
How to Choose a Compact Submersible Centrifugal Pump: Start With Head
To choose a compact submersible centrifugal pump, start with head, the height the pump has to push the liquid. Flow falls as head rises, and every model has a maximum head where flow stops. The Mfr # 503103 listing shows the pattern: 500 GPH of water at 1 ft of head, 337 GPH at 5 ft and 210 GPH at 10 ft, with a listed maximum head of 17.3 ft.
The Hydraulic Institute calls the head and flow curve the most commonly used curve to describe pump performance. It defines shut-off head as the pump head at zero flow, where no liquid is flowing through the pump but the pump is primed and running. The listings in the collection label this number Max. Head or shutoff, and it runs from 4.6 ft to 17.3 ft across the pumps compared below.
Key takeaways
- Choose by head first: flow falls as head rises, and each pump has a maximum head.
- The listings compared here range from 4.6 ft to 17.3 ft of maximum head, where a maximum is listed.
- Check the fluid, materials, voltage, connections and Mfr # against the manufacturer's data before you order.
Head and Flow in the Pumps We List
Most of the Little Giant Pump listings in the collection give flow at 1 ft of head. The bars below compare eight of them, picked to cover the range from the smallest flow to the largest. A pump with a high flow at 1 ft is not necessarily the right one for a taller lift, so read the maximum head in the table next to it.
- Mfr # 523375: 120 GPH
- Mfr # 500203: 170 GPH
- Mfr # 501203: 205 GPH
- Mfr # 526003: 210 GPH
- Mfr # 502375: 300 GPH
- Mfr # 518600: 475 GPH
- Mfr # 503103: 500 GPH
- Mfr # 503603: 670 GPH
Source: product listings in the Compact Submersible Centrifugal Pumps collection, Little Giant Pump data as listed, read October 19, 2026. Bars are rounded to the nearest 5%.
| Mfr # | HP | GPH at 1 ft | Max head | Seal |
|---|---|---|---|---|
| 523375 | 1/160 | 120 | 4.6 ft | Nitrile |
| 500203 | 1/200 | 170 | 7 ft | Nitrile |
| 501203 | 1/150 | 205 | 7.4 ft | Nitrile |
| 526003 | 1/150 | 210 | 10.2 ft | Viton |
| 502375 | 1/40 | 300 | 11.8 ft | Nitrile |
| 518600 | Not listed | 475 | 13.4 ft | Fluoroelastomer |
| 503103 | 1/15 | 500 | 17.3 ft | Viton |
| 503603 | 1/15 | 670 | Not listed (260 GPH at 15 ft) | Not listed |
The drop in flow as head rises is easy to see when a listing gives more than one head. Four of the listings that do are below:
| Mfr # | At 1 ft | At 5 ft | At 10 ft |
|---|---|---|---|
| 518400 | 300 | 240 | 130 |
| 502375 | 300 | 205 | 70 |
| 518600 | 475 | 395 | 205 |
| 503103 | 500 | 337 | 210 |
Two listings can also look alike and still differ. The 503103 and the 503375 list the same flows (500, 337 and 210 GPH at 1, 5 and 10 ft), but the 503103 lists a maximum head of 17.3 ft and the 503375 lists 16.8 ft. Read the maximum head line on each listing instead of assuming that similar pumps match.
Fluids, Materials and Duty: What the Listing Tells You
A listing's materials tell you what the pump is made of. They do not say which fluids it can handle, so use them to compare models and then confirm the fluid with the manufacturer. These are the points the listings in this collection cover:
- Housing: nylon, polypropylene or cast aluminum. Some listings give two housing materials, so confirm with the manufacturer.
- Impeller: nylon or polypropylene.
- Seal: nitrile, Viton or fluoroelastomer, depending on the model.
- Duty: most list continuous duty, and the 502303 lists intermittent duty.
- Temperature: several list a maximum media temperature of 120°F.
- Motor protection: overload protection or thermal overload protection is listed on most.
What are you pumping?
Water, for recirculation or transfer
Look at listings that name water transfer or recirculation as the pumping application, such as the Mfr # 518400 (12.2 ft maximum head, continuous duty) and the Mfr # 500500 (7 ft maximum head, includes a garden hose adapter).
Machine tool coolant or oil
The Mfr # 502375 lists machine tool coolants among its applications and oil under compatible media. Confirm the fluid with the manufacturer first.
Mild acids or alkalis
The Mfr # 526003 is described as a pump designed to be used in mild acids, alkalis and hardware applications, with a nylon housing, cover, volute and impeller and a Viton shaft seal. The listing does not define "mild," so check your fluid and its concentration with the manufacturer.
I am not sure
Write down the fluid, its temperature and the head you need, then compare them with the manufacturer's data for the model. If a listing leaves a question open, contact us with the product name or Mfr #.
Warning: Listings do not always agree. The 502303 and the 502375 are both 1/40 HP and list the same flows, 300, 205 and 70 GPH at 1, 5 and 10 ft. Yet the 502303 is listed as submersible when pumping water or machine oils only, and the 502375 lists mild acids among its applications. Confirm your fluid with the manufacturer before you order.
Connections, Cords and Electrical Data
The head and the fluid narrow the field. Connections and electrical data decide whether a pump fits the job you already have. To match a pump you are replacing, work through these steps:
- Find the Mfr # of the pump you are replacing. Look on the pump or in its paperwork, then search for it in the collection. You should land on one listing, or on a close match to compare.
- Match voltage and amps. The listings in this collection that state a voltage list 115 V, and the listed amps run from 0.5 A to 3.2 A. You should keep only the pumps with your voltage and a similar amp draw.
- Match head and flow at your height. Compare GPH at 1, 5 and 10 ft and the maximum head with the lift in your system. You should end with pumps whose maximum head clears your lift.
- Match inlet and outlet. Most list a 1/4 in. (M)NPT outlet, the 518600 lists 3/8 in. (M)NPT, and the 503103 lists a 1/2 in. (F)NPT inlet with a 1/2 in. (M)NPT outlet. You should know which fittings or adapters you need.
- Check the cord and connection. Cords are listed from 6 ft to 18 ft, and the 518400 and the 500500 are listed as plug-in and hardwired, in that order. You should know whether the pump fits your outlet or wiring.
Follow the manufacturer's manual for installation. For the electrical side, a qualified electrician can confirm what your site requires.
Questions About Compact Submersible Pumps
What does max head mean on a listing?
It is the highest lift a pump can reach, the point where flow stops. The Hydraulic Institute defines shut-off head as the pump head at zero flow with the pump primed and running, and says operating at that point for more than a few seconds can cause serious mechanical issues. Plan your system below the listed maximum head.
Can I use one in line instead of submerged?
Some listings say so. The 501203, 503103 and 503375 list "In-line or Submersible." Other listings describe submersible use, so check the model's manual before you install a pump in line.
Are these pumps for drinking water?
Do not assume so. The 566608 is listed for non-potable submersible use, and the other listings do not state an approval for potable water. If your application involves drinking water, confirm it with the manufacturer.
What comes with the pump?
It depends on the listing. The 500500 lists a garden hose adapter and the 503603 lists none. The 502375 lists a pre-screen, and the 502303 lists a 6 ft SJTOW-A cord set. Read the Includes line on each listing before you order.
The Bottom Line: What to Remember When You Buy a Compact Submersible Pump
- Start with head. Flow falls as head rises, so the maximum head must clear the lift in your system.
- Read flow at your height. A pump's flow at 1 ft says little about its flow at 10 ft, and the listings show the drop.
- Confirm the fluid with the manufacturer. Materials help you compare models, and only the manufacturer's data says what a model can handle.
- Match voltage, amps, connections and cord. The listings give each one, and they differ between models.
- Order by Mfr #. It ties the pump you have to its listing.
Shop Compact Submersible Centrifugal Pumps at Contractor Supplies
The Compact Submersible Centrifugal Pumps collection at Contractor Supplies lists the pumps compared above. For a different kind of job, see our submersible sump pumps and deep well submersible pumps. Before you order, read the shipping page and the return and refund policies. More buying guides are in the News blog.
Here are some of the products in our Compact Submersible Centrifugal Pumps collection:
Up to about 10 ft of maximum head
- Pump, 4 In. L, 3 In. W, 4 In. H (Mfr # 523375)
- 4-1/4 in. x 4-1/4 in. x 4-1/4 in. Pump (Mfr # 500203)
- Pump, 4-1/4 In. L, 4-1/8 In. W, 4-1/4 In. H (Mfr # 500500)
- Pump, 4-15/16 In. L, 2-3/4 In. W (Mfr # 566608)
- 3-1/2 in. x 2-3/4 in. x 3-5/8 in. Pump (Mfr # 518200)
- Pump, 4-1/2 In. L, 4-1/2 In. W, 4-5/8 In. H (Mfr # 501203)
- 1/150 HP Submersible Centrifugal Pump (Mfr # 526003)
11 to 13.4 ft of maximum head
- 5-1/2 in. x 3-1/2 in. x 4-3/4 in. Pump (Mfr # 502103)
- Submersible Centrifugal Pump, 1/40 HP (Mfr # 502303)
- Pump, 5-1/2 In. L, 3-1/2 In. W, 4-3/4 In. H (Mfr # 502375)
- Pump, 4-17/32 In. L, 2-5/8 In. W (Mfr # 518400)
- Pump, 4-5/8 In. L, 2-7/8 In. W, 5-1/4 In. H (Mfr # 518600)
16.8 ft of maximum head and up, or not listed
- 7 in. x 4-1/2 in. x 5-1/2 in. Pump (Mfr # 503103)
- Pump, 7 In. L, 4-1/2 In. W, 5-1/2 In. H (Mfr # 503375)
- Pump, circulating, 670gph, 115V (Mfr # 503603)
Find a compact pump by head and flow
Compare maximum head, flow, materials and connections across the full collection.